187 results on '"Sjoerd Hoogland"'
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2. Enhanced optical path and electron diffusion length enable high-efficiency perovskite tandems
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Bin Chen, Se-Woong Baek, Yi Hou, Erkan Aydin, Michele De Bastiani, Benjamin Scheffel, Andrew Proppe, Ziru Huang, Mingyang Wei, Ya-Kun Wang, Eui-Hyuk Jung, Thomas G. Allen, Emmanuel Van Kerschaver, F. Pelayo García de Arquer, Makhsud I. Saidaminov, Sjoerd Hoogland, Stefaan De Wolf, and Edward H. Sargent
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Science - Abstract
Metal-halide perovskite based tandem solar cells are appealing but making a high efficiency device is not trivial. Here Chen et al. increase the carrier collection in the perovskite layer and largely enhance the efficiency in tandem cells when combined with colloidal quantum dot or silicon layers.
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- 2020
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3. Cascade surface modification of colloidal quantum dot inks enables efficient bulk homojunction photovoltaics
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Min-Jae Choi, F. Pelayo García de Arquer, Andrew H. Proppe, Ali Seifitokaldani, Jongmin Choi, Junghwan Kim, Se-Woong Baek, Mengxia Liu, Bin Sun, Margherita Biondi, Benjamin Scheffel, Grant Walters, Dae-Hyun Nam, Jea Woong Jo, Olivier Ouellette, Oleksandr Voznyy, Sjoerd Hoogland, Shana O. Kelley, Yeon Sik Jung, and Edward. H. Sargent
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Science - Abstract
It is challenging to realize doping and surface passivation simultaneously in colloidal quantum dot inks. Here Choi et al. employ a cascade surface modification approach to solve the problem and obtain record high efficiency of 13.3% for bulk homojunction solar cells based on these inks.
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- 2020
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4. Quantum Dot Self‐Assembly Enables Low‐Threshold Lasing
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Chun Zhou, Joao M. Pina, Tong Zhu, Darshan H. Parmar, Hao Chang, Jie Yu, Fanglong Yuan, Golam Bappi, Yi Hou, Xiaopeng Zheng, Jehad Abed, Hao Chen, Jian Zhang, Yuan Gao, Bin Chen, Ya‐Kun Wang, Haijie Chen, Tianju Zhang, Sjoerd Hoogland, Makhsud I. Saidaminov, Liaoxin Sun, Osman M. Bakr, Hongxing Dong, Long Zhang, and Edward H. Sargent
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Auger recombination ,lasing ,perovskites ,quantum dots ,superlattices ,Science - Abstract
Abstract Perovskite quantum dots (QDs) are of interest for solution‐processed lasers; however, their short Auger lifetime has limited lasing operation principally to the femtosecond temporal regime the photoexcitation levels to achieve optical gain threshold are up to two orders of magnitude higher in the nanosecond regime than in the femtosecond. Here the authors report QD superlattices in which the gain medium facilitates excitonic delocalization to decrease Auger recombination and in which the macroscopic dimensions of the structures provide the optical feedback required for lasing. The authors develope a self‐assembly strategy that relies on sodiumd—an assembly director that passivates the surface of the QDs and induces self‐assembly to form ordered three‐dimensional cubic structures. A density functional theory model that accounts for the attraction forces between QDs allows to explain self‐assembly and superlattice formation. Compared to conventional organic‐ligand‐passivated QDs, sodium enables higher attractive forces, ultimately leading to the formation of micron‐length scale structures and the optical faceting required for feedback. Simultaneously, the decreased inter‐dot distance enabled by the new ligand enhances exciton delocalization among QDs, as demonstrated by the dynamically red‐shifted photoluminescence. These structures function as the lasing cavity and the gain medium, enabling nanosecond‐sustained lasing with a threshold of 25 µJ cm–2.
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- 2021
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5. Colloidal Quantum Dot Bulk Heterojunction Solids with Near‐Unity Charge Extraction Efficiency
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Min‐Jae Choi, Se‐Woong Baek, Seungjin Lee, Margherita Biondi, Chao Zheng, Petar Todorovic, Peicheng Li, Sjoerd Hoogland, Zheng‐Hong Lu, F. Pelayo García deArquer, and Edward H. Sargent
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bulk heterojunctions ,colloidal quantum dots ,doping ,infrared optoelectronics ,light harvesting ,Science - Abstract
Abstract Colloidal quantum dots (CQDs) are of interest for optoelectronic applications owing to their tunable properties and ease of processing. Large‐diameter CQDs offer optical response in the infrared (IR), beyond the bandgap of c‐Si and perovskites. The absorption coefficient of IR CQDs (≈104 cm−1) entails the need for micrometer‐thick films to maximize the absorption of IR light. This exceeds the thickness compatible with the efficient extraction of photogenerated carriers, a fact that limits device performance. Here, CQD bulk heterojunction solids are demonstrated that, with extended carrier transport length, enable efficient IR light harvesting. An in‐solution doping strategy for large‐diameter CQDs is devised that addresses the complex interplay between (100) facets and doping agents, enabling to control CQD doping, energetic configuration, and size homogeneity. The hetero‐offset between n‐type CQDs and p‐type CQDs is manipulated to drive the transfer of electrons and holes into distinct carrier extraction pathways. This enables to form active layers exceeding thicknesses of 700 nm without compromising open‐circuit voltage and fill factor. As a result, >90% charge extraction efficiency across the ultraviolet to IR range (350–1400 nm) is documented.
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- 2020
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6. High Color Purity Lead‐Free Perovskite Light‐Emitting Diodes via Sn Stabilization
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Hongyan Liang, Fanglong Yuan, Andrew Johnston, Congcong Gao, Hitarth Choubisa, Yuan Gao, Ya‐Kun Wang, Laxmi Kishore Sagar, Bin Sun, Peicheng Li, Golam Bappi, Bin Chen, Jun Li, Yunkun Wang, Yitong Dong, Dongxin Ma, Yunan Gao, Yongchang Liu, Mingjian Yuan, Makhsud I. Saidaminov, Sjoerd Hoogland, Zheng‐Hong Lu, and Edward H. Sargent
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antioxidation ,H3PO2 additives ,lead‐free perovskites ,Sn‐based red light‐emitting diodes ,Sn stabilization ,Science - Abstract
Abstract Perovskite‐based light‐emitting diodes (PeLEDs) are now approaching the upper limits of external quantum efficiency (EQE); however, their application is currently limited by reliance on lead and by inadequate color purity. The Rec. 2020 requires Commission Internationale de l'Eclairage coordinates of (0.708, 0.292) for red emitters, but present‐day perovskite devices only achieve (0.71, 0.28). Here, lead‐free PeLEDs are reported with color coordinates of (0.706, 0.294)—the highest purity reported among red PeLEDs. The variation of the emission spectrum is also evaluated as a function of temperature and applied potential, finding that emission redshifts by
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- 2020
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7. Multibandgap quantum dot ensembles for solar-matched infrared energy harvesting
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Bin Sun, Olivier Ouellette, F. Pelayo García de Arquer, Oleksandr Voznyy, Younghoon Kim, Mingyang Wei, Andrew H. Proppe, Makhsud I. Saidaminov, Jixian Xu, Mengxia Liu, Peicheng Li, James Z. Fan, Jea Woong Jo, Hairen Tan, Furui Tan, Sjoerd Hoogland, Zheng Hong Lu, Shana O. Kelley, and Edward H. Sargent
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Science - Abstract
Efficient harvest of solar energy beyond the silicon absorption edge of 1100 nm by semiconductor solar cells remains a challenge. Here Sun et al. mix high multi-bandgap lead sulfide colloidal quantum dot ensembles to further increase both short circuit current and open circuit voltage.
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- 2018
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8. Mixed-quantum-dot solar cells
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Zhenyu Yang, James Z. Fan, Andrew H. Proppe, F. Pelayo García de Arquer, David Rossouw, Oleksandr Voznyy, Xinzheng Lan, Min Liu, Grant Walters, Rafael Quintero-Bermudez, Bin Sun, Sjoerd Hoogland, Gianluigi A. Botton, Shana O. Kelley, and Edward H. Sargent
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Science - Abstract
Solution processed colloidal quantum dots are emerging photovoltaic materials with tuneable infrared bandgaps. Here, Yang et al. create a class of quantum dot bulk heterojunction solar cell via ligand design, enabling longer photocarrier diffusion lengths for greater photocurrent and performance.
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- 2017
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9. Field-emission from quantum-dot-in-perovskite solids
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F. Pelayo García de Arquer, Xiwen Gong, Randy P. Sabatini, Min Liu, Gi-Hwan Kim, Brandon R. Sutherland, Oleksandr Voznyy, Jixian Xu, Yuangjie Pang, Sjoerd Hoogland, David Sinton, and Edward Sargent
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Science - Abstract
Efficient implementation of quantum dot and well architectures are restricted to costly vacuum-epitaxially-grown semiconductors. The authors use quantum dots in perovskite to build field-emission photodiodes that are sensitive across the visible and into the short-wavelength infrared.
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- 2017
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10. Control over Charge Carrier Mobility in the Hole Transport Layer Enables Fast Colloidal Quantum Dot Infrared Photodetectors
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Ozan Atan, Joao M. Pina, Darshan H. Parmar, Pan Xia, Yangning Zhang, Ahmet Gulsaran, Eui Dae Jung, Dongsun Choi, Muhammad Imran, Mustafa Yavuz, Sjoerd Hoogland, and Edward H. Sargent
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Mechanical Engineering ,General Materials Science ,Bioengineering ,General Chemistry ,Condensed Matter Physics - Published
- 2023
11. Near-Unity Broadband Quantum Efficiency Enabled by Colloidal Quantum Dot/Mixed-Organic Heterojunction
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Yujin Jung, Hyeyoung Shin, Se-Woong Baek, Truong Ba Tai, Benjamin Scheffel, Olivier Ouellette, Margherita Biondi, Sjoerd Hoogland, F. Pelayo García de Arquer, and Edward H. Sargent
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Fuel Technology ,Renewable Energy, Sustainability and the Environment ,Chemistry (miscellaneous) ,Materials Chemistry ,Energy Engineering and Power Technology - Published
- 2023
12. Bifunctional Electron-Transporting Agent for Red Colloidal Quantum Dot Light-Emitting Diodes
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Ya-Kun Wang, Haoyue Wan, Jian Xu, Yun Zhong, Eui Dae Jung, So Min Park, Sam Teale, Muhammad Imran, You-Jun Yu, Pan Xia, Yu-Ho Won, Kwang-Hee Kim, Zheng-Hong Lu, Liang-Sheng Liao, Sjoerd Hoogland, and Edward H. Sargent
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Colloid and Surface Chemistry ,General Chemistry ,Biochemistry ,Catalysis - Published
- 2023
13. Enhanced Blue Emission in Rb2HfCl6 Double Perovskite via Bi3+ Doping and Cs+ Alloying
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Haoyue Wan, Fengyan Jia, Filip Dinic, Muhammad Imran, Benjamin Rehl, Yanjiang Liu, Watcharaphol Paritmongkol, Pan Xia, Ya-Kun Wang, Yuan Liu, Sasa Wang, Quan Lyu, Giovanni Francesco Cotella, Peter Chun, Oleksandr Voznyy, Sjoerd Hoogland, and Edward H. Sargent
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General Chemical Engineering ,Materials Chemistry ,General Chemistry - Published
- 2023
14. Quantum-Size-Effect Tuning Enables Narrowband IR Photodetection with Low Sunlight Interference
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Joao M. Pina, Maral Vafaie, Darshan H. Parmar, Ozan Atan, Pan Xia, Yangning Zhang, Amin M. Najarian, F. Pelayo García de Arquer, Sjoerd Hoogland, and Edward H. Sargent
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Mechanical Engineering ,General Materials Science ,Bioengineering ,General Chemistry ,Condensed Matter Physics - Abstract
Infrared photodetection enables depth imaging techniques such as structured light and time-of-flight. Traditional photodetectors rely on silicon (Si); however, the bandgap of Si limits photodetection to wavelengths shorter than 1100 nm. Photodetector operation centered at 1370 nm benefits from lower sunlight interference due to atmospheric absorption. Here, we report 1370 nm-operating colloidal quantum dot (CQD) photodetectors and evaluate their outdoor performance. We develop a surface-ligand engineering strategy to tune the electronic properties of each CQD layer and fabricate photodetectors in an inverted (PIN) architecture. The strategy enables photodetectors with an external quantum efficiency of 75% and a low dark current (1 μA/cm
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- 2022
15. Sequential Co‐Passivation in InAs Colloidal Quantum Dot Solids Enables Efficient Near‐Infrared Photodetectors
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Pan Xia, Bin Sun, Margherita Biondi, Jian Xu, Ozan Atan, Muhammad Imran, Yasser Hassan, Yanjiang Liu, Joao M. Pina, Amin Morteza Najarian, Luke Grater, Koen Bertens, Laxmi Kishore Sagar, Husna Anwar, Min‐Jae Choi, Yangning Zhang, Minhal Hasham, F. Pelayo García de Arquer, Sjoerd Hoogland, Mark W. B. Wilson, and Edward H. Sargent
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Mechanics of Materials ,Mechanical Engineering ,General Materials Science - Published
- 2023
16. Sub-millimetre light detection and ranging using perovskites
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Amin Morteza Najarian, Maral Vafaie, Andrew Johnston, Tong Zhu, Mingyang Wei, Makhsud I. Saidaminov, Yi Hou, Sjoerd Hoogland, F. Pelayo García de Arquer, and Edward H. Sargent
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Electrical and Electronic Engineering ,Instrumentation ,Electronic, Optical and Magnetic Materials - Published
- 2022
17. Quantum-size-tuned heterostructures enable efficient and stable inverted perovskite solar cells
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Hao Chen, Sam Teale, Bin Chen, Yi Hou, Luke Grater, Tong Zhu, Koen Bertens, So Min Park, Harindi R. Atapattu, Yajun Gao, Mingyang Wei, Andrew K. Johnston, Qilin Zhou, Kaimin Xu, Danni Yu, Congcong Han, Teng Cui, Eui Hyuk Jung, Chun Zhou, Wenjia Zhou, Andrew H. Proppe, Sjoerd Hoogland, Frédéric Laquai, Tobin Filleter, Kenneth R. Graham, Zhijun Ning, and Edward H. Sargent
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Atomic and Molecular Physics, and Optics ,Electronic, Optical and Magnetic Materials - Published
- 2022
18. Rigid Conjugated Diamine Templates for Stable Dion–Jacobson-Type Two-Dimensional Perovskites
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Randy P. Sabatini, Amin Morteza Najjarian, Alan J. Lough, Dwight S. Seferos, Ruyan Zhao, Sasa Wang, Tong Zhu, Andrew Johnston, Sjoerd Hoogland, and Edward H. Sargent
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Ligand ,02 engineering and technology ,General Chemistry ,Conjugated system ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,chemistry.chemical_compound ,Crystallography ,symbols.namesake ,Crystallinity ,Colloid and Surface Chemistry ,chemistry ,Diamine ,Thiophene ,symbols ,Density functional theory ,van der Waals force ,0210 nano-technology ,Bifunctional - Abstract
Hybrid organic-inorganic perovskites (HOIPs) have garnered widespread interest, yet stability remains a critical issue that limits their further application. Compared to their three-dimensional (3D) counterparts, two-dimensional (2D)-HOIPs exhibit improved stability. 2D-HOIPs are also appealing because their structural and optical properties can be tuned according to the choice of organic ligand, with monovalent or divalent ligands forming Ruddlesden-Popper (RP) or Dion-Jacobson (DJ)-type 2D perovskites, respectively. Unlike RP-type 2D perovskites, DJ-type 2D perovskites do not contain a van der Waals gap between the 2D layers, leading to improved stability. However, bifunctional organic ligands currently used to develop DJ-type 2D perovskites are limited to commercially available aliphatic and single-ring aromatic ammonium cations. Large conjugated organic ligands are in demand for their semiconducting properties and their potential to improve materials stability further. In this manuscript, we report the design and synthesis of a new set of larger conjugated diamine ligands and their incorporation into DJ-type 2D perovskites. Compared with analogous RP-type 2D perovskites, DJ 2D perovskites reported here show blue-shifted, narrower emissions and significantly improved stability. By changing the structure of rings (benzene vs thiophene) and substituents, we develop structure-property relationships, finding that fluorine substitution enhances crystallinity. Single-crystal structure analysis and density functional theory calculations indicate that these changes are due to strong electrostatic interactions between the organic templates and inorganic layers as well as the rigid backbone and strong π-π interaction between the organic ligands themselves. These results illustrate that targeted engineering of the diamine ligands can enhance the stability of DJ-type 2D perovskites.
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- 2021
19. Dipole Engineering through the Orientation of Interface Molecules for Efficient InP Quantum Dot Light-Emitting Diodes
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Seungjin Lee, So Min Park, Eui Dae Jung, Tong Zhu, Joao M. Pina, Husna Anwar, Feng-Yi Wu, Guan-Lin Chen, Yitong Dong, Teng Cui, Mingyang Wei, Koen Bertens, Ya-Kun Wang, Bin Chen, Tobin Filleter, Sung-Fu Hung, Yu-Ho Won, Kwang Hee Kim, Sjoerd Hoogland, and Edward H. Sargent
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Colloid and Surface Chemistry ,General Chemistry ,Biochemistry ,Catalysis - Abstract
InP-based quantum dot (QD) light-emitting diodes (QLEDs) provide a heavy-metal-free route to size-tuned LEDs having high efficiency. The stability of QLEDs may be enhanced by replacing organic hole-injection layers (HILs) with inorganic layers. However, inorganic HILs reported to date suffer from inefficient hole injection, the result of their shallow work functions. Here, we investigate the tuning of the work function of nickel oxide (NiO
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- 2022
20. Bright and Stable Light-Emitting Diodes Based on Perovskite Quantum Dots in Perovskite Matrix
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Kamalpreet Singh, Eui Hyuk Jung, Oleksandr Voznyy, Tong Zhu, Fanglong Yuan, Bin Chen, Chao Zheng, Laxmi Kishore Sagar, Ya-Kun Wang, Seungjin Lee, Min-Jae Choi, Zheng-Hong Lu, Bin Sun, Dongxin Ma, Yitong Dong, Sjoerd Hoogland, F. Pelayo García de Arquer, Yi Hou, Andrew H. Proppe, Shana O. Kelley, Edward H. Sargent, and Yuan Liu
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Passivation ,business.industry ,Chemistry ,Exciton ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Biochemistry ,Catalysis ,0104 chemical sciences ,law.invention ,Colloid and Surface Chemistry ,Quantum dot ,law ,Optoelectronics ,Quantum efficiency ,0210 nano-technology ,Luminescence ,business ,Diode ,Perovskite (structure) ,Light-emitting diode - Abstract
Light-emitting diodes (LEDs) based on metal halide perovskite quantum dots (QDs) have achieved impressive external quantum efficiencies; however, the lack of surface protection of QDs, combined with efficiency droop, decreases device operating lifetime at brightnesses of interest. The epitaxial incorporation of QDs within a semiconducting shell provides surface passivation and exciton confinement. Achieving this goal in the case of perovskite QDs remains an unsolved challenge in view of the materials' chemical instability. Here, we report perovskite QDs that remain stable in a thin layer of precursor solution of perovskite, and we use strained QDs as nucleation centers to drive the homogeneous crystallization of a perovskite matrix. Type-I band alignment ensures that the QDs are charge acceptors and radiative emitters. The new materials show suppressed Auger bi-excition recombination and bright luminescence at high excitation (600 W cm-2), whereas control materials exhibit severe bleaching. Primary red LEDs based on the new materials show an external quantum efficiency of 18%, and these retain high performance to brightnesses exceeding 4700 cd m-2. The new materials enable LEDs having an operating half-life of 2400 h at an initial luminance of 100 cd m-2, representing a 100-fold enhancement relative to the best primary red perovskite LEDs.
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- 2021
21. Engineering Electro-Optic BaTiO
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Sasa, Wang, Tong, Zhu, Randy, Sabatini, Amin Morteza, Najarian, Muhammad, Imran, Ruyan, Zhao, Pan, Xia, Lewei, Zeng, Sjoerd, Hoogland, Dwight S, Seferos, and Edward H, Sargent
- Abstract
Electro-optic (EO) modulators provide electrical-to-optical signal conversion relevant to optical communications. Barium titanate (BaTiO
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- 2022
22. Electron-Transport Layers Employing Strongly Bound Ligands Enhance Stability in Colloidal Quantum Dot Infrared Photodetectors
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Yangning Zhang, Maral Vafaie, Jian Xu, Joao M. Pina, Pan Xia, Amin M. Najarian, Ozan Atan, Muhammad Imran, Ke Xie, Sjoerd Hoogland, and Edward H. Sargent
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Mechanics of Materials ,Mechanical Engineering ,General Materials Science - Abstract
Solution-processed photodetectors based on colloidal quantum dots (CQDs) are promising candidates for short-wavelength infrared light sensing applications. Present-day CQD photodetectors employ a CQD active layer sandwiched between carrier-transport layers in which the electron-transport layer (ETL) is composed of metal oxides. Herein, a new class of ETLs is developed using n-type CQDs, finding that these benefit from quantum-size effect tuning of the band energies, as well as from surface ligand engineering. Photodetectors operating at 1450 nm are demonstrated using CQDs with tailored functionalities for each of the transport layers and the active layer. By optimizing the band alignment between the ETL and the active layer, CQD photodetectors that combine a low dark current of ≈1 × 10
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- 2022
23. Engineering hydrogen bonding to align molecular dipoles in organic solids for efficient second harmonic generation
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Ruyan Zhao, Tong Zhu, Sasa Wang, Charlie Jarrett-Wilkins, Amin Morteza Najjarian, Alan J. Lough, Sjoerd Hoogland, Edward H. Sargent, and Dwight S. Seferos
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General Chemistry - Abstract
Considering nearly infinite design possibilities, organic second harmonic generation (SHG) molecules are believed to have long-term promise. However, because of the tendency to form dipole-antiparallel crystals that lead to zero macroscopic polarization, it is difficult to design a nonlinear optical (NLO) material based on organic molecules. In this manuscript, we report a new molecule motif that can form asymmetric organic solids by controlling the degree of hydrogen bonding through protonation. A conjugated polar organic molecule was prepared with a triple bond connecting an electron-withdrawing pyridine ring and an electron-donating thiophene ring. By controlling the degree of hydrogen bonding through protonation, two different crystal packing motifs are achieved. One crystallizes into the common dipole-antiparallel nonpolar
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- 2022
24. Control Over Ligand Exchange Reactivity in Hole Transport Layer Enables High-Efficiency Colloidal Quantum Dot Solar Cells
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Sjoerd Hoogland, F. Pelayo García de Arquer, Edward H. Sargent, Zheng-Hong Lu, Koen Bertens, Geonhui Lee, Hao Ting Kung, Min-Jae Choi, Seungjin Lee, Mingyang Wei, Ahmad R. Kirmani, Lee J. Richter, and Margherita Biondi
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Materials science ,Infrared ,Energy Engineering and Power Technology ,Hole transport layer ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,7. Clean energy ,Quantitative Biology::Cell Behavior ,Colloid ,Materials Chemistry ,Astrophysics::Solar and Stellar Astrophysics ,Reactivity (chemistry) ,Renewable Energy, Sustainability and the Environment ,business.industry ,Solar spectra ,Ligand ,Photovoltaic system ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Fuel Technology ,Chemistry (miscellaneous) ,Quantum dot ,Physics::Space Physics ,Optoelectronics ,Astrophysics::Earth and Planetary Astrophysics ,0210 nano-technology ,business - Abstract
Colloidal quantum dot (CQD) solar cells are solution-processed photovoltaic devices that exhibit promise in harvesting the infrared solar spectrum. Solid-state ligand exchange is the method employe...
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- 2021
25. InP-Quantum-Dot-in-ZnS-Matrix Solids for Thermal and Air Stability
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Xiyan Li, Bin Chen, Yitong Dong, Laxmi Kishore Sagar, Edward H. Sargent, Larissa Levina, Yuan Gao, Dongxin Ma, Sjoerd Hoogland, Seungjin Lee, Aidan Grenville, and F. Pelayo García de Arquer
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Photoluminescence ,Materials science ,General Chemical Engineering ,Shell (structure) ,Physics::Optics ,Quantum yield ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,7. Clean energy ,Condensed Matter::Materials Science ,Laser linewidth ,Matrix (mathematics) ,Thermal ,Materials Chemistry ,Condensed Matter::Other ,business.industry ,General Chemistry ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,3. Good health ,Core (optical fiber) ,Quantum dot ,Optoelectronics ,0210 nano-technology ,business - Abstract
InP/ZnS core/shell colloidal quantum dots (QDs) are promising candidates as Cd- and Pb-free emitters owing to their high photoluminescence quantum yield, narrow emission linewidth, and color tunabi...
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- 2020
26. Colloidal Quantum Dot Solar Cell Band Alignment using Two-Step Ionic Doping
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Peicheng Li, Margherita Biondi, Seungjin Lee, James Z. Fan, Armin Sedighian Rasouli, Koen Bertens, Sjoerd Hoogland, F. Pelayo García de Arquer, Bin Sun, Edward H. Sargent, and Zheng-Hong Lu
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Electron mobility ,Materials science ,Passivation ,business.industry ,General Chemical Engineering ,Doping ,Biomedical Engineering ,Ionic bonding ,Halide ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,7. Clean energy ,01 natural sciences ,0104 chemical sciences ,law.invention ,Colloid ,law ,Quantum dot ,Solar cell ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business - Abstract
Colloidal quantum dot (CQD) solar cells composed of ionic halide passivated active layers benefit from improved passivation and high carrier mobility because of short interparticle distance. Howeve...
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- 2020
27. Orthogonal colloidal quantum dot inks enable efficient multilayer optoelectronic devices
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F. Pelayo García de Arquer, Laxmi Kishore Sagar, Geetu Sharma, Amin Morteza Najarian, Maral Vafaie, Margherita Biondi, Bin Chen, Min-Jae Choi, Joshua Wicks, Se-Woong Baek, Edward H. Sargent, Seungjin Lee, Sjoerd Hoogland, and Oleksandr Voznyy
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Solar cells ,Materials science ,Fabrication ,Science ,General Physics and Astronomy ,Hole transport layer ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Article ,General Biochemistry, Genetics and Molecular Biology ,Colloid ,lcsh:Science ,Multidisciplinary ,Inkwell ,Quantum dots ,business.industry ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Dipole ,Quantum dot ,Optoelectronics ,Quantum efficiency ,lcsh:Q ,Colloidal quantum dots ,0210 nano-technology ,business - Abstract
Surface ligands enable control over the dispersibility of colloidal quantum dots (CQDs) via steric and electrostatic stabilization. Today’s device-grade CQD inks have consistently relied on highly polar solvents: this enables facile single-step deposition of multi-hundred-nanometer-thick CQD films; but it prevents the realization of CQD film stacks made up of CQDs having different compositions, since polar solvents redisperse underlying films. Here we introduce aromatic ligands to achieve process-orthogonal CQD inks, and enable thereby multifunctional multilayer CQD solids. We explore the effect of the anchoring group of the aromatic ligand on the solubility of CQD inks in weakly-polar solvents, and find that a judicious selection of the anchoring group induces a dipole that provides additional CQD-solvent interactions. This enables colloidal stability without relying on bulky insulating ligands. We showcase the benefit of this ink as the hole transport layer in CQD optoelectronics, achieving an external quantum efficiency of 84% at 1210 nm., The realisation of film made up of different compositions using colloidal QD inks remains a challenge because of redispersing of underlying films by polar solvents. Here, the authors introduce aromatic ligands to achieve QD inks in weakly-polar solvents that enable fabrication of multi-compositional films.
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- 2020
28. Suppression of Auger Recombination by Gradient Alloying in InAs/CdSe/CdS QDs
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Larissa Levina, Andrew Johnston, Sjoerd Hoogland, Bin Chen, Petar Todorović, Makhsud I. Saidaminov, Edward H. Sargent, Laxmi Kishore Sagar, Min-Jae Choi, Golam Bappi, Dae-Hyun Nam, F. Pelayo García de Arquer, and Oleksandr Voznyy
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Materials science ,Physics::Instrumentation and Detectors ,General Chemical Engineering ,Physics::Optics ,Photodetector ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,7. Clean energy ,law.invention ,Condensed Matter::Materials Science ,symbols.namesake ,law ,Materials Chemistry ,Diode ,Auger effect ,Condensed Matter::Other ,business.industry ,General Chemistry ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,021001 nanoscience & nanotechnology ,Laser ,0104 chemical sciences ,Quantum dot ,symbols ,Optoelectronics ,Colloidal quantum dots ,0210 nano-technology ,business ,Light-emitting diode - Abstract
Colloidal quantum dots are promising for low-cost optoelectronic devices such as solar cells, light-emitting diodes (LEDs), lasers, and photodetectors. InAs-based quantum dots (QDs) are well suited...
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- 2020
29. High-Performance Perovskite Single-Junction and Textured Perovskite/Silicon Tandem Solar Cells via Slot-Die-Coating
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Stefaan De Wolf, Jiang Liu, Francesco Furlan, Shynggys Zhumagali, Thomas Allen, Anand S. Subbiah, Erkan Aydin, Furkan Halis Isikgor, Sjoerd Hoogland, Fuzong Xu, Michele De Bastiani, Edward H. Sargent, Calvyn Travis Howells, and Iain McCulloch
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Materials science ,Tandem ,Silicon ,Renewable Energy, Sustainability and the Environment ,business.industry ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Die (integrated circuit) ,0104 chemical sciences ,Fuel Technology ,Planar ,Coating ,chemistry ,Chemistry (miscellaneous) ,Materials Chemistry ,engineering ,Optoelectronics ,0210 nano-technology ,business ,Perovskite (structure) - Abstract
In this work, we report perovskite solar cells in the planar p–i–n configuration based on single-step, anti-solvent-free, low-temperature (70 °C) slot-die-coated methylammonium lead tri-iodide (MAP...
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- 2020
30. Bipolar-shell resurfacing for blue LEDs based on strongly confined perovskite quantum dots
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Min-Jae Choi, Oleksandr Voznyy, Mahshid Chekini, Ya-Kun Wang, Eugenia Kumacheva, Yuan Liu, Dongxin Ma, Hinako Ebe, Se-Woong Baek, Yitong Dong, James Z. Fan, Zheng-Hong Lu, Rafael Quintero-Bermudez, Fanglong Yuan, Yi Hou, Liang-Sheng Liao, Sjoerd Hoogland, Edward H. Sargent, Laxmi Kishore Sagar, Bin Sun, Petar Todorović, Bin Chen, Filip Dinic, Makhsud I. Saidaminov, Andrew Johnston, Seungjin Lee, Peicheng Li, Hao Ting Kung, Erdmann Spiecker, and Mingjian Wu
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Electron mobility ,Photoluminescence ,Materials science ,business.industry ,Biomedical Engineering ,Quantum yield ,Bioengineering ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Ion ,Semiconductor ,Quantum dot ,Optoelectronics ,General Materials Science ,Quantum efficiency ,Electrical and Electronic Engineering ,0210 nano-technology ,business ,Perovskite (structure) - Abstract
Colloidal quantum dot (QD) solids are emerging semiconductors that have been actively explored in fundamental studies of charge transport1 and for applications in optoelectronics2. Forming high-quality QD solids—necessary for device fabrication—requires substitution of the long organic ligands used for synthesis with short ligands that provide increased QD coupling and improved charge transport3. However, in perovskite QDs, the polar solvents used to carry out the ligand exchange decompose the highly ionic perovskites4. Here we report perovskite QD resurfacing to achieve a bipolar shell consisting of an inner anion shell, and an outer shell comprised of cations and polar solvent molecules. The outer shell is electrostatically adsorbed to the negatively charged inner shell. This approach produces strongly confined perovskite QD solids that feature improved carrier mobility (≥0.01 cm2 V−1 s−1) and reduced trap density relative to previously reported low-dimensional perovskites. Blue-emitting QD films exhibit photoluminescence quantum yields exceeding 90%. By exploiting the improved mobility, we have been able to fabricate CsPbBr3 QD-based efficient blue and green light-emitting diodes. Blue devices with reduced trap density have an external quantum efficiency of 12.3%; the green devices achieve an external quantum efficiency of 22%. A solution-based ligand-exchange strategy enables the realization of close-packed quantum dot solid films with near-unity photoluminescence quantum yield and high charge carrier mobility.
- Published
- 2020
31. Multiple Self-Trapped Emissions in the Lead-Free Halide Cs3Cu2I5
- Author
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Zoltán Zajacz, Joao M. Pina, Xiyan Li, Fanglong Yuan, Zheng-Hong Lu, Sjoerd Hoogland, Ziliang Li, Edward H. Sargent, Antoine Dumont, Andrew Johnston, Haijie Chen, Bin Chen, Yanan Liu, and Dongxin Ma
- Subjects
010302 applied physics ,Materials science ,Physics::Optics ,Halide ,chemistry.chemical_element ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Photochemistry ,01 natural sciences ,7. Clean energy ,Copper ,High luminance ,Condensed Matter::Materials Science ,Lead (geology) ,chemistry ,0103 physical sciences ,Physics::Atomic and Molecular Clusters ,Physics::Accelerator Physics ,General Materials Science ,Physical and Theoretical Chemistry ,0210 nano-technology ,Luminescence - Abstract
Low-dimensional copper halides with high luminance have attracted increasing interest as heavy-metal-free light emitters. However, the optical mechanisms underpinning their excellent luminescence r...
- Published
- 2020
32. Single-Precursor Intermediate Shelling Enables Bright, Narrow Line Width InAs/InZnP-Based QD Emitters
- Author
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Larissa Levina, Laxmi Kishore Sagar, Sjoerd Hoogland, Edward H. Sargent, Bin Chen, Makhsud I. Saidaminov, Petar Todorović, F. Pelayo García de Arquer, Andrew Johnston, and Golam Bappi
- Subjects
Photoluminescence ,Materials science ,Infrared ,business.industry ,General Chemical Engineering ,Quantum yield ,02 engineering and technology ,General Chemistry ,Photodetection ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Full width at half maximum ,Quantum dot ,Materials Chemistry ,Radiative transfer ,Optoelectronics ,Spontaneous emission ,0210 nano-technology ,business - Abstract
Bright, narrow spectrum infrared emitters, particularly Cd- and Pb-free materials, are of interest for bioimaging, photodetection, and telecommunications. InAs-based quantum dots (QDs) are promising emitters in this spectral range; however, efforts to increase the photoluminescence quantum yield (PLQY) tend to broaden the PL line width as a consequence of interfacial defect formation when thick shells, lattice-mismatched with the core, are employed. Here we report that developing a single-precursor complex for InZnP growth enables uniform shell growth that maintains the excellent size dispersion (6%) of the cores. The introduction of this intermediate layer is key to facilitate the subsequent growth of different shells to improve radiative recombination without sacrificing size uniformity. The growth of InAs/InZnP/ZnSe leads to a PL full-width at half-maximum (fwhm) of 100 meV at 1.12 eV with a PLQY of 14%. We then further introduce an additional GaP layer to increase the radiative/nonradiative relative rate. InAs/InZnP/GaP/ZnSe QDs reach a PLQY of 23% while maintaining a narrow fwhm.
- Published
- 2020
33. Engineering Directionality in Quantum Dot Shell Lasing Using Plasmonic Lattices
- Author
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Jun Guan, Oleksandr Voznyy, Edward H. Sargent, Golam Bappi, Laxmi Kishore Sagar, Danqing Wang, Ran Li, Fengjia Fan, Marc R. Bourgeois, Nicolas E. Watkins, George C. Schatz, Teri W. Odom, Sjoerd Hoogland, Richard D. Schaller, Joao M. Pina, and Larissa Levina
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Materials science ,business.industry ,Mechanical Engineering ,Nanolaser ,Physics::Optics ,Bioengineering ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Waveguide (optics) ,Brillouin zone ,Quantum dot ,Lattice (order) ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business ,Electronic band structure ,Lasing threshold ,Plasmon - Abstract
We report how the direction of quantum dot (QD) lasing can be engineered by exploiting high-symmetry points in plasmonic nanoparticle (NP) lattices. The nanolaser architecture consists of CdSe-CdS core-shell QD layers conformally coated on two-dimensional square arrays of Ag NPs. Using waveguide-surface lattice resonances (W-SLRs) near the Δ point in the Brillouin zone as optical feedback, we achieved lasing from the gain in CdS shells at off-normal emission angles. Changing the periodicity of the plasmonic lattices enables other high-symmetry points (Γ or M) of the lattice to overlap with the QD shell emission, which facilitates tuning of the lasing direction. We also increased the thickness of the QD layer to introduce higher-order W-SLR modes with additional avoided crossings in the band structure, which expands the selection of cavity modes for any desired lasing emission angle.
- Published
- 2020
34. Cascade surface modification of colloidal quantum dot inks enables efficient bulk homojunction photovoltaics
- Author
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Grant Walters, Andrew H. Proppe, Shana O. Kelley, Sjoerd Hoogland, Yeon Sik Jung, Junghwan Kim, F. Pelayo García de Arquer, Jongmin Choi, Mengxia Liu, Bin Sun, Benjamin Scheffel, Ali Seifitokaldani, Jea Woong Jo, Olivier Ouellette, Oleksandr Voznyy, Min-Jae Choi, Margherita Biondi, Se-Woong Baek, Dae-Hyun Nam, and Edward H. Sargent
- Subjects
Solar cells ,Passivation ,Science ,General Physics and Astronomy ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,7. Clean energy ,Article ,General Biochemistry, Genetics and Molecular Biology ,Physics::Popular Physics ,Photovoltaics ,Homojunction ,lcsh:Science ,Multidisciplinary ,Quantum dots ,business.industry ,Synthesis and processing ,Energy conversion efficiency ,Doping ,Heterojunction ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Quantum dot ,Optoelectronics ,Surface modification ,lcsh:Q ,0210 nano-technology ,business - Abstract
Control over carrier type and doping levels in semiconductor materials is key for optoelectronic applications. In colloidal quantum dots (CQDs), these properties can be tuned by surface chemistry modification, but this has so far been accomplished at the expense of reduced surface passivation and compromised colloidal solubility; this has precluded the realization of advanced architectures such as CQD bulk homojunction solids. Here we introduce a cascade surface modification scheme that overcomes these limitations. This strategy provides control over doping and solubility and enables n-type and p-type CQD inks that are fully miscible in the same solvent with complete surface passivation. This enables the realization of homogeneous CQD bulk homojunction films that exhibit a 1.5 times increase in carrier diffusion length compared with the previous best CQD films. As a result, we demonstrate the highest power conversion efficiency (13.3%) reported among CQD solar cells., It is challenging to realize doping and surface passivation simultaneously in colloidal quantum dot inks. Here Choi et al. employ a cascade surface modification approach to solve the problem and obtain record high efficiency of 13.3% for bulk homojunction solar cells based on these inks.
- Published
- 2020
35. Efficient hybrid colloidal quantum dot/organic solar cells mediated by near-infrared sensitizing small molecules
- Author
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Andrew H. Proppe, Edward H. Sargent, F. Pelayo García de Arquer, Olivier Ouellette, Sjoerd Hoogland, Hye Ryung Byun, Byeongsu Kim, Se-Woong Baek, Sunhong Jun, Sohee Jeong, Jung-Yong Lee, Mun Seok Jeong, Junho Kim, Changjo Kim, Jung Hoon Song, Grant Walters, Shana O. Kelley, and Oleksandr Voznyy
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chemistry.chemical_classification ,Materials science ,Organic solar cell ,Renewable Energy, Sustainability and the Environment ,business.industry ,Exciton ,Energy Engineering and Power Technology ,Nanotechnology ,02 engineering and technology ,Polymer ,Hybrid solar cell ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Fuel Technology ,Semiconductor ,chemistry ,Quantum dot ,Photovoltaics ,0210 nano-technology ,Absorption (electromagnetic radiation) ,business - Abstract
Solution-processed semiconductors are promising materials to realize optoelectronic devices that combine high performance with inexpensive manufacturing. In particular, the exploitation of colloidal quantum dots (CQDs) capable of harvesting infrared photons, in conjunction with visible-absorbing organic chromophores, has been demonstrated as an interesting route. Unfortunately, CQD/organic hybrid photovoltaics have been limited to power conversion efficiencies (PCEs) below 10% due to chemical mismatch and difficulties in facilitating charge collection. Here we devise a hybrid architecture that overcomes these limitations by introducing small molecules into the CQD/organic stacked structure. The small molecule complements CQD absorption and creates an exciton cascade with the host polymer, thus enabling efficient energy transfer and also promoting exciton dissociation at heterointerfaces. The resulting hybrid solar cells exhibit PCEs of 13.1% and retain over 80% of their initial PCE after 150 h of continuous operation unencapsulated, outperforming present air-processed solution-cast CQD/organic photovoltaics. Colloidal quantum dots and organics have complementary properties apt for photovoltaics, yet their combination has led to poor charge collection. Here, Baek et al. introduce small molecules that act as a bridge between quantum dots and polymers, thus improving device efficiency and stability.
- Published
- 2019
36. Quantum Dot Self-Assembly Enables Low-Threshold Lasing
- Author
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Joao M. Pina, Ya-Kun Wang, Osman M. Bakr, Bin Chen, Jehad Abed, Makhsud I. Saidaminov, Yuan Gao, Chun Zhou, Hao Chen, Hongxing Dong, Jie Yu, Xiaopeng Zheng, Long Zhang, Haijie Chen, Edward H. Sargent, Fanglong Yuan, Golam Bappi, Tianju Zhang, Sjoerd Hoogland, Hao Chang, Darshan H. Parmar, Tong Zhu, Jian Zhang, Yi Hou, and Liaoxin Sun
- Subjects
Photoluminescence ,Materials science ,Active laser medium ,superlattices ,Science ,General Chemical Engineering ,Exciton ,Superlattice ,perovskites ,General Physics and Astronomy ,Medicine (miscellaneous) ,Physics::Optics ,quantum dots ,02 engineering and technology ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,03 medical and health sciences ,symbols.namesake ,Condensed Matter::Materials Science ,Auger recombination ,General Materials Science ,Research Articles ,030304 developmental biology ,0303 health sciences ,lasing ,Auger effect ,business.industry ,General Engineering ,021001 nanoscience & nanotechnology ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,Quantum dot ,Femtosecond ,symbols ,Optoelectronics ,0210 nano-technology ,business ,Lasing threshold ,Research Article - Abstract
Perovskite quantum dots (QDs) are of interest for solution‐processed lasers; however, their short Auger lifetime has limited lasing operation principally to the femtosecond temporal regime the photoexcitation levels to achieve optical gain threshold are up to two orders of magnitude higher in the nanosecond regime than in the femtosecond. Here the authors report QD superlattices in which the gain medium facilitates excitonic delocalization to decrease Auger recombination and in which the macroscopic dimensions of the structures provide the optical feedback required for lasing. The authors develope a self‐assembly strategy that relies on sodiumd—an assembly director that passivates the surface of the QDs and induces self‐assembly to form ordered three‐dimensional cubic structures. A density functional theory model that accounts for the attraction forces between QDs allows to explain self‐assembly and superlattice formation. Compared to conventional organic‐ligand‐passivated QDs, sodium enables higher attractive forces, ultimately leading to the formation of micron‐length scale structures and the optical faceting required for feedback. Simultaneously, the decreased inter‐dot distance enabled by the new ligand enhances exciton delocalization among QDs, as demonstrated by the dynamically red‐shifted photoluminescence. These structures function as the lasing cavity and the gain medium, enabling nanosecond‐sustained lasing with a threshold of 25 µJ cm–2., The manipulation of the surface properties of quantum dots can be used to control their self‐assembly into macroscopic structures that provide the required optical feedback for lasing. Here the use of a ligand that passivates the quantum dot surface and simultaneously induce self‐assembly into superlattice structures that sustain low‐threshold lasing is reported.
- Published
- 2021
37. Reply to: Perovskite decomposition and missing crystal planes in HRTEM
- Author
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Andrei Buin, Edward H. Sargent, Zhijun Ning, Fengjia Fan, Grant Walters, Riccardo Comin, Emre Yassitepe, Xiwen Gong, Sjoerd Hoogland, and Oleksandr Voznyy
- Subjects
Crystal ,Titanium ,Crystallography ,Multidisciplinary ,Materials science ,Microscopy, Electron, Transmission ,Oxides ,Calcium Compounds ,High-resolution transmission electron microscopy ,Decomposition ,Perovskite (structure) - Published
- 2021
38. Stable Colloidal Quantum Dot Inks Enable Inkjet-Printed High-Sensitivity Infrared Photodetectors
- Author
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Min-Jae Choi, Sachin Kinge, Tapio Fabritius, F. Pelayo García de Arquer, Rafal Sliz, Edward H. Sargent, James Z. Fan, Marc Lejay, and Sjoerd Hoogland
- Subjects
Materials science ,business.industry ,Infrared ,General Engineering ,Physics::Optics ,General Physics and Astronomy ,Photodetector ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Colloid ,Quantum dot ,Optoelectronics ,General Materials Science ,Colloidal quantum dots ,Sensitivity (control systems) ,0210 nano-technology ,business - Abstract
Colloidal quantum dots (CQDs) have recently gained attention as materials for manufacturing optoelectronic devices in view of their tunable light absorption and emission properties and compatibility with low-temperature thin-film manufacture. The realization of CQD inkjet-printed infrared photodetectors has thus far been hindered by incompatibility between the chemical processes that produce state-of-the-art CQD solution-exchanged inks and the requirements of ink formulations for inkjet materials processing. To achieve inkjet-printed CQD solids with a high degree of reproducibility, as well as with the needed morphological and optoelectronic characteristics, we sought to overcome the mismatch among these processing conditions. In this study, we design CQD inks by simultaneous evaluation of requirements regarding ink colloidal stability, jetting conditions, and film morphology for different dots and solvents. The new inks remain colloidally stable, achieved through a design that suppresses the reductant properties of amines on the dots' surface. After drop ejection from the nozzle, the quantum dot material is immobilized on the substrate surface due to the rapid evaporation of the low boiling point amine-based compound. Concurrently, the high boiling point solvent allows for the formation of a thin film of high uniformity, as is required for the fabrication of high-performance IR photodetectors. We fabricate inkjet-printed photodetectors exhibiting the highest specific detectivities reported to date (above 10
- Published
- 2019
39. Lattice anchoring stabilizes solution-processed semiconductors
- Author
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Andrew H. Proppe, F. Pelayo García de Arquer, Mengxia Liu, Bin Sun, Grant Walters, Chih Shan Tan, Rahim Munir, Shana O. Kelley, Hairen Tan, Yuelang Chen, Rafael Quintero-Bermudez, Oleksandr Voznyy, Andrew Pak Tao Kam, Min-Jae Choi, Benjamin Scheffel, Sjoerd Hoogland, Edward H. Sargent, and Aram Amassian
- Subjects
Multidisciplinary ,Photoluminescence ,Materials science ,business.industry ,Band gap ,Chalcogenide ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,Semiconductor ,chemistry ,Optoelectronics ,Quantum efficiency ,0210 nano-technology ,Hybrid material ,business ,Perovskite (structure) - Abstract
The stability of solution-processed semiconductors remains an important area for improvement on their path to wider deployment. Inorganic caesium lead halide perovskites have a bandgap well suited to tandem solar cells1 but suffer from an undesired phase transition near room temperature2. Colloidal quantum dots (CQDs) are structurally robust materials prized for their size-tunable bandgap3; however, they also require further advances in stability because they are prone to aggregation and surface oxidization at high temperatures as a consequence of incomplete surface passivation4,5. Here we report ‘lattice-anchored’ hybrid materials that combine caesium lead halide perovskites with lead chalcogenide CQDs, in which lattice matching between the two materials contributes to a stability exceeding that of the constituents. We find that CQDs keep the perovskite in its desired cubic phase, suppressing the transition to the undesired lattice-mismatched phases. The stability of the CQD-anchored perovskite in air is enhanced by an order of magnitude compared with pristine perovskite, and the material remains stable for more than six months at ambient conditions (25 degrees Celsius and about 30 per cent humidity) and more than five hours at 200 degrees Celsius. The perovskite prevents oxidation of the CQD surfaces and reduces the agglomeration of the nanoparticles at 100 degrees Celsius by a factor of five compared with CQD controls. The matrix-protected CQDs show a photoluminescence quantum efficiency of 30 per cent for a CQD solid emitting at infrared wavelengths. The lattice-anchored CQD:perovskite solid exhibits a doubling in charge carrier mobility as a result of a reduced energy barrier for carrier hopping compared with the pure CQD solid. These benefits have potential uses in solution-processed optoelectronic devices. The stability of both colloidal quantum dots and perovskites can be improved by combining them into a hybrid material in which matched lattice parameters suppress the formation of undesired phases.
- Published
- 2019
40. Controlled Steric Hindrance Enables Efficient Ligand Exchange for Stable, Infrared-Bandgap Quantum Dot Inks
- Author
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Oleksandr Voznyy, Rafael Quintero-Bermudez, F. Pelayo García de Arquer, Sjoerd Hoogland, Mengxia Liu, Andrew H. Proppe, Andreas Mandelis, Fanglin Che, Mingyang Wei, Lilei Hu, Shana O. Kelley, Bin Sun, Rahim Munir, Edward H. Sargent, and Aram Amassian
- Subjects
Steric effects ,Materials science ,Fabrication ,Renewable Energy, Sustainability and the Environment ,business.industry ,Band gap ,Infrared ,Ligand ,Physics::Optics ,Energy Engineering and Power Technology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,7. Clean energy ,0104 chemical sciences ,Fuel Technology ,Chemistry (miscellaneous) ,Quantum dot ,Materials Chemistry ,Optoelectronics ,Astrophysics::Earth and Planetary Astrophysics ,Colloidal quantum dots ,0210 nano-technology ,business - Abstract
Colloidal quantum dots (CQDs), which benefit from a size-tuned bandgap, are a solution-processed material for infrared energy harvesting. This characteristic enables the fabrication of solar cells ...
- Published
- 2019
41. Infrared Cavity-Enhanced Colloidal Quantum Dot Photovoltaics Employing Asymmetric Multilayer Electrodes
- Author
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Jongmin Choi, F. Pelayo García de Arquer, Jung-Yong Lee, Se-Woong Baek, Min-Jae Choi, Olivier Ouellette, Ki-Won Seo, Dae-Hyun Nam, Bin Sun, Edward H. Sargent, Junghwan Kim, Li Na Quan, Sjoerd Hoogland, Sang Hoon Lee, Jea Woong Jo, and Juhoon Kang
- Subjects
Materials science ,Silicon ,Infrared ,Oxide ,Energy Engineering and Power Technology ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,7. Clean energy ,01 natural sciences ,chemistry.chemical_compound ,Photovoltaics ,Materials Chemistry ,Transmittance ,Sheet resistance ,Renewable Energy, Sustainability and the Environment ,business.industry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Fuel Technology ,chemistry ,Chemistry (miscellaneous) ,Quantum dot ,Optoelectronics ,0210 nano-technology ,business ,Refractive index - Abstract
Efficient infrared (IR) optoelectronic devices, crucial for emerging sensing applications and also for solar energy harvesting, demand high-conductivity IR-transparent electrodes. Here we present a new strategy, one based on oxide/metal/oxide multilayers, that enables highly transparent IR electrodes. Symmetry breaking in the oxide stack leads to broad and high transmittance from visible to IR wavelengths, while a low refractive index doped oxide as a front layer boosts IR transmittance. The combination of doped oxide and ultrathin metal film allows for low sheet resistance while maintaining IR transparency. We engineer the IR microcavity effect using the asymmetric multilayer approach to tailor the distribution of incident radiation to maximize IR absorption in the colloidal quantum dot (CQD) layer. As a result, the absorption-enhanced IR CQD solar cells exhibit a photoelectric conversion efficiency of 70% at a wavelength of 1.25 μm, i.e., well within the spectral range in which silicon is blind.
- Published
- 2018
42. Electro-Optic Modulation Using Metal-Free Perovskites
- Author
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Amin Morteza Najarian, Edward H. Sargent, Ding-Jiang Xue, Sjoerd Hoogland, Meng-Jia Sun, Oleksandr Voznyy, Qixin Feng, Grant Walters, Chao Zheng, Yuan Gao, Xiaoping Wang, Ya-Kun Wang, Shadi Meshkat, Makhsud I. Saidaminov, and Andrew Johnston
- Subjects
Materials science ,Silicon photonics ,business.industry ,Neutron diffraction ,02 engineering and technology ,Crystal structure ,021001 nanoscience & nanotechnology ,01 natural sciences ,Pockels effect ,010309 optics ,Crystal ,Modulation ,0103 physical sciences ,Optoelectronics ,General Materials Science ,Density functional theory ,0210 nano-technology ,business ,Perovskite (structure) - Abstract
Electro-optic (EO) modulation is of interest to impart information onto an optical carrier. Inorganic crystals-most notably LiNbO3 and BaTiO3-exhibit EO modulation and good stability, but are difficult to integrate with silicon photonic technology. Solution-processed organic EO materials are readily integrated but suffer from thermal degradation at the temperatures required in operating conditions for accelerated reliability studies. Hybrid organic-inorganic metal halide perovskites have the potential to overcome these limitations; however, these have so far relied on heavy metals such as lead and cadmium. Here, we report linear EO modulation using metal-free perovskites, which maintain the crystalline features of the inorganic EO materials and incorporate the flexible functionality of organic EO chromophores. We find that, by introducing a deficiency of cations, we reduce the symmetry in the perovskite crystal and produce thereby an increased EO response. The best-engineered perovskites reported herein showcase an EO coefficient of 14 pm V-1 at a modulation frequency of 80 kHz, an order of magnitude higher than in the nondefective materials. We observe split peaks in the X-ray diffraction and neutron diffraction patterns of the defective sample, indicating that the crystalline structure has been distorted and the symmetry reduced. Density functional theory (DFT) studies link this decreased symmetry to NH4+ deficiencies. This demonstration of EO from metal-free perovskites highlights their potential in next-generation optical information transmission.
- Published
- 2021
43. Facet-Oriented Coupling Enables Fast and Sensitive Colloidal Quantum Dot Photodetectors
- Author
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Yuguang C. Li, Oleksandr Voznyy, Laxmi Kishore Sagar, Edward H. Sargent, Bin Sun, Zhibo Wang, Petar Todorović, Min-Jae Choi, Sjoerd Hoogland, Hitarth Choubisa, F. Pelayo García de Arquer, Koen Bertens, Bin Chen, Dae-Hyun Nam, Armin Sedighian Rasouli, Se-Woong Baek, Seungjin Lee, Margherita Biondi, Maral Vafaie, Amin Morteza Najarian, and Mingyang Wei
- Subjects
Electron mobility ,Materials science ,Passivation ,business.industry ,Mechanical Engineering ,Photodetector ,02 engineering and technology ,Specific detectivity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Photodiode ,law.invention ,Mechanics of Materials ,Quantum dot ,law ,Optoelectronics ,General Materials Science ,Quantum efficiency ,Charge carrier ,0210 nano-technology ,business - Abstract
Charge carrier transport in colloidal quantum dot (CQD) solids is strongly influenced by coupling among CQDs. The shape of as-synthesized CQDs results in random orientational relationships among facets in CQD solids, and this limits the CQD coupling strength and the resultant performance of optoelectronic devices. Here, colloidal-phase reconstruction of CQD surfaces, which improves facet alignment in CQD solids, is reported. This strategy enables control over CQD faceting and allows demonstration of enhanced coupling in CQD solids. The approach utilizes post-synthetic resurfacing and unites surface passivation and colloidal stability with a propensity for dots to couple via (100):(100) facets, enabling increased hole mobility. Experimentally, the CQD solids exhibit a 10× increase in measured hole mobility compared to control CQD solids, and enable photodiodes (PDs) exhibiting 70% external quantum efficiency (vs 45% for control devices) and specific detectivity, D* > 1012 Jones, each at 1550 nm. The photodetectors feature a 7 ns response time for a 0.01 mm2 area-the fastest reported for solution-processed short-wavelength infrared PDs.
- Published
- 2021
44. Structural Distortion and Bandgap Increase of Two-Dimensional Perovskites Induced by Trifluoromethyl Substitution on Spacer Cations
- Author
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Zhaomin Hao, Oleksandr Voznyy, Edward H. Sargent, Pei-Xi Wang, Sjoerd Hoogland, Amin Morteza Najarian, and Andrew Johnston
- Subjects
chemistry.chemical_classification ,Trifluoromethyl ,Materials science ,010405 organic chemistry ,Band gap ,Iodide ,Halide ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Blueshift ,chemistry.chemical_compound ,Crystallography ,chemistry ,Halogen ,General Materials Science ,Density functional theory ,Physical and Theoretical Chemistry ,Perovskite (structure) - Abstract
In further advancing display technologies, especially for improved blue emitters, to engineer the bandgap of promising semiconductors such as hybrid perovskites is important. Present-day methods for tuning the bandgaps of perovskites, such as the incorporation of mixed halide anions, suffer drawbacks such as phase separation and difficulty in synthesis. Here we report a new 2D lead iodide perovskite that emits in the blue spectral region. We exploit an increased angular distortion of PbI42- octahedra to widen the bandgap of 2D metal halide perovskites. We synthesized 2D lead iodide perovskites based on (4-Y-C6H4CH2NH3)2PbI4 (Y = H, F, Cl, Br, I) and substituted the halogen atoms with a -CF3 group to create (4-CF3-C6H4CH2NH3)2PbI4 compounds. We observed that the CF3-substituted material exhibited a ∼0.16 eV larger bandgap than did the halogen-substituted materials. We used X-ray diffraction and density functional theory simulations and found that the blue shift can be assigned to the angular distortion of the PbI42- lattice, a distortion traceable to repulsive intermolecular interactions between the trifluoromethyl groups on oppositely-arranged spacers. These results add a degree of freedom in tuning 2D perovskites to selected bandgaps for optoelectronic applications.
- Published
- 2020
45. Controlled Crystal Plane Orientations in the ZnO Transport Layer Enable High‐Responsivity, Low‐Dark‐Current Infrared Photodetectors
- Author
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Darshan H. Parmar, Joao M. Pina, Tong Zhu, Maral Vafaie, Ozan Atan, Margherita Biondi, Amin M. Najjariyan, Sjoerd Hoogland, and Edward H. Sargent
- Subjects
Mechanics of Materials ,Mechanical Engineering ,General Materials Science - Abstract
Colloidal quantum dots (CQD) have emerged as attractive materials for infrared (IR) photodetector (PD) applications because of their tunable bandgaps and facile processing. Presently, zinc oxide is the electron-transport layer (ETL) of choice in CQD PDs; however, ZnO relies on continuous ultraviolet (UV) illumination to remove adsorbed oxygen and maintain high external quantum efficiency (EQE), speed, and photocurrent. Here, it is shown that ZnO is dominated by electropositive crystal planes which favor excessive oxygen adsorption, and that this leads to a high density of trap states, an undesired shift in band alignment, and consequent poor performance. Over prolonged operation without UV exposure, oxygen accumulates at the electropositive planes, trapping holes and degrading performance. This problem is addressed by developing an electroneutral plane composition at the ZnO surface, aided by atomic layer deposition (ALD) as the means of materials processing. It is found that ALD ZnO has 10× lower binding energy for oxygen than does conventionally deposited ZnO. IR CQD PDs made with this ETL do not require UV activation to maintain low dark current and high EQE.
- Published
- 2022
46. Deep-Blue Perovskite Single-Mode Lasing through Efficient Vapor-Assisted Chlorination
- Author
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Maral Vafaie, Yitong Dong, Amin Morteza Najarian, Chun Zhou, Golam Bappi, Laxmi Kishore Sagar, Joao M. Pina, Edward H. Sargent, Hitarth Choubisa, Darshan H. Parmar, Sjoerd Hoogland, Makhsud I. Saidaminov, Yuan Gao, and Koen Bertens
- Subjects
Amplified spontaneous emission ,Active laser medium ,Materials science ,business.industry ,Mechanical Engineering ,Single-mode optical fiber ,Gain ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Laser ,01 natural sciences ,0104 chemical sciences ,law.invention ,Mechanics of Materials ,law ,Optoelectronics ,General Materials Science ,Thin film ,0210 nano-technology ,business ,Lasing threshold ,Perovskite (structure) - Abstract
Metal halide perovskites have emerged as promising candidates for solution-processed laser gain materials, with impressive performance in the green and red spectral regions. Despite exciting progress, deep-blue-an important wavelength for laser applications-remains underexplored; indeed, cavity integration and single-mode lasing from large-bandgap perovskites have yet to be achieved. Here, a vapor-assisted chlorination strategy that enables synthesis of low-dimensional CsPbCl3 thin films exhibiting deep-blue emission is reported. Using this approach, high-quality perovskite thin films having a low surface roughness (RMS ≈ 1.3 nm) and efficient charge transfer properties are achieved. These enable us to document low-threshold amplified spontaneous emission. Levering the high quality of the gain medium, vertical-cavity surface-emitting lasers with a low lasing threshold of 6.5 µJ cm-2 are fabricated. This report of deep-blue perovskite single-mode lasing showcases the prospect of increasing the range of deep-blue laser sources.
- Published
- 2020
47. A Tuned Alternating D-A Copolymer Hole-Transport Layer Enables Colloidal Quantum Dot Solar Cells with Superior Fill Factor and Efficiency
- Author
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Seung Un Ryu, Sjoerd Hoogland, Kyoungwon Choi, Soon-Ki Kwon, Min-Jae Choi, Edward H. Sargent, Seungjin Lee, Yun-Hi Kim, F P García de Arquer, Taiho Park, Hong Il Kim, Hyung Jin Cheon, Margherita Biondi, and Se-Woong Baek
- Subjects
chemistry.chemical_classification ,Conductive polymer ,Electron mobility ,Materials science ,Absorption spectroscopy ,business.industry ,Mechanical Engineering ,Photovoltaic system ,02 engineering and technology ,Polymer ,010402 general chemistry ,021001 nanoscience & nanotechnology ,7. Clean energy ,01 natural sciences ,0104 chemical sciences ,Active layer ,Molecular engineering ,chemistry ,Mechanics of Materials ,Quantum dot ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business - Abstract
The need for optoelectronic and chemical compatibility between the layers in colloidal quantum dot (CQD) photovoltaic devices remains a bottleneck in further increasing performance. Conjugated polymers are promising candidates as new hole-transport layer (HTL) materials in CQD solar cells (CQD-SCs) owing to the highly tunable optoelectronic properties and compatible chemistries. A diketopyrrolopyrrole-based polymer with benzothiadiazole derivatives (PD2FCT-29DPP) as an HTL in these devices is reported. The energy level, molecular orientation, and hole mobility of this HTL are manipulated through molecular engineering. By levering the polymer's optical absorption spectrum complementary to that of the CQD active layer, EQE across the visible and near-infrared regions is maximized. As a result, a PD2FCT-29DPP-based device exhibits a fill factor of 70% and approximately 35% efficiency enhancement compared to a PTB7-based device.
- Published
- 2020
48. Monolithic Organic/Colloidal Quantum Dot Hybrid Tandem Solar Cells via Buffer Engineering
- Author
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Taiho Park, Hong Il Kim, Min-Jae Choi, Hyuntae Choi, Se-Woong Baek, F. Pelayo García de Arquer, Edward H. Sargent, Olivier Ouellette, Benjamin Scheffel, Margherita Biondi, Sjoerd Hoogland, Kyoungwon Choi, and Bin Chen
- Subjects
Materials science ,Organic solar cell ,Tandem ,business.industry ,Infrared ,Mechanical Engineering ,Energy conversion efficiency ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,7. Clean energy ,01 natural sciences ,0104 chemical sciences ,Colloid ,Mechanics of Materials ,Quantum dot ,Optoelectronics ,General Materials Science ,0210 nano-technology ,business ,Absorption (electromagnetic radiation) ,Layer (electronics) - Abstract
Monolithically integrated hybrid tandem solar cells (TSCs) that combine solution-processed colloidal quantum dot (CQD) and organic molecules are a promising device architecture, able to complement the absorption across the visible to the infrared. However, the performance of organic/CQD hybrid TSCs has not yet surpassed that of single-junction CQD solar cells. Here, a strategic optical structure is devised to overcome the prior performance limit of hybrid TSCs by employing a multibuffer layer and a dual near-infrared (NIR) absorber. In particular, a multibuffer layer is introduced to solve the problem of the CQD solvent penetrating the underlying organic layer. In addition, the matching current of monolithic TSCs is significantly improved to 15.2 mA cm-2 by using a dual NIR organic absorber that complements the absorption of CQD. The hybrid TSCs reach a power conversion efficiency (PCE) of 13.7%, higher than that of the corresponding individual single-junction cells, representing the highest efficiency reported to date for CQD-based hybrid TSCs.
- Published
- 2020
49. Micron Thick Colloidal Quantum Dot Solids
- Author
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Mykhailo Sytnyk, Bin Chen, Frédéric Laquai, Andrew H. Proppe, Wolfgang Heiss, Koen Bertens, Armin Sedighian Rasouli, Se-Woong Baek, Joao M. Pina, Olivier Ouellette, Edward H. Sargent, Maral Vafaie, Laxmi Kishore Sagar, F. Pelayo García de Arquer, Sjoerd Hoogland, Yajun Gao, and James Z. Fan
- Subjects
Photon ,Materials science ,business.industry ,Mechanical Engineering ,Exciton ,Resonance ,Bioengineering ,02 engineering and technology ,General Chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,7. Clean energy ,Colloid ,Semiconductor ,Quantum dot ,Dispersion (optics) ,Optoelectronics ,General Materials Science ,Quantum efficiency ,0210 nano-technology ,business - Abstract
Shortwave infrared colloidal quantum dots (SWIR-CQDs) are semiconductors capable of harvesting across the AM1.5G solar spectrum. Today's SWIR-CQD solar cells rely on spin-coating; however, these films exhibit cracking once thickness exceeds ∼500 nm. We posited that a blade-coating strategy could enable thick QD films. We developed a ligand exchange with an additional resolvation step that enabled the dispersion of SWIR-CQDs. We then engineered a quaternary ink that combined high-viscosity solvents with short QD stabilizing ligands. This ink, blade-coated over a mild heating bed, formed micron-thick SWIR-CQD films. These SWIR-CQD solar cells achieved short-circuit current densities (Jsc) that reach 39 mA cm-2, corresponding to the harvest of 60% of total photons incident under AM1.5G illumination. External quantum efficiency measurements reveal both the first exciton peak and the closest Fabry-Perot resonance peak reaching approximately 80%-this is the highest unbiased EQE reported beyond 1400 nm in a solution-processed semiconductor.
- Published
- 2020
50. Multiple Self-Trapped Emissions in the Lead-Free Halide Cs
- Author
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Haijie, Chen, Joao M, Pina, Fanglong, Yuan, Andrew, Johnston, Dongxin, Ma, Bin, Chen, Ziliang, Li, Antoine, Dumont, Xiyan, Li, Yanan, Liu, Sjoerd, Hoogland, Zoltán, Zajacz, Zhenghong, Lu, and Edward H, Sargent
- Abstract
Low-dimensional copper halides with high luminance have attracted increasing interest as heavy-metal-free light emitters. However, the optical mechanisms underpinning their excellent luminescence remain underexplored. Here, we report multiple self-trapped emissions in Cs
- Published
- 2020
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