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143 results on '"Guo, Kunping"'

4. Additive solution deposition of multi-layered semiconducting polymer films for design of sophisticated device architectures

Author

Murrey, Tucker L, Guo, Kunping, Mulvey, Justin T, Lee, Owen A, Cendra, Camila, Bedolla-Valdez, Zaira I, Salleo, Alberto, Moulin, Jean-Francois, Hong, Kunlun, and Moulé, Adam J

Subjects
Engineering, Macromolecular and Materials Chemistry, Materials Engineering, Chemical Sciences, Physical Chemistry (incl. Structural), Macromolecular and materials chemistry, Physical chemistry, Materials engineering
Abstract

Many organic electronic devices require vertically layered structures to operate. This manuscript demonstrates an additive solution process for depositing multiple layers of semiconducting polymer (SP) films by controlling film solubility with molecular dopants. During multi-layer deposition the bottom layers are exposed to a series of solvent environments that swell the SP films. We use neutron reflectometry (NR) to quantify the film thickness change and solvent content during solvent exposure in a single poly-3-hexylthiophene (P3HT) layer. The film thickness increases by 40-80% with exposure to good solvents. Four layer thin-films composed of alternating protonated and deuterated P3HT layers were additively coated from solution. NR measurements reveal high individual layer purity and that extensive solvent soaking induces no mixing between layers. Finally, two-point conductivity measurements demonstrate that P3HT:P3HT layer interfaces have no effect on vertical conductivity. This facile process enables additive layering of mutually soluble SP films and can be used to design novel electronic device architectures.

Published
2019

5. Facile Nanowelding Process for Silver Nanowire Electrodes Toward High‐Performance Large‐Area Flexible Organic Light‐Emitting Diodes.

Author

Du, Mengyang, Yang, Zhuo, Miao, Yanqin, Wang, Chao, Dong, Peng, Wang, Hua, and Guo, Kunping

Subjects
ELECTRIC conductivity, QUANTUM efficiency, POLYETHYLENE terephthalate, ORGANIC light emitting diodes, DIODES, NANOWIRES
Abstract

Despite considerable interest, uniform and robust flexible transparent conducting electrodes (FTCEs) that can be seamlessly integrated and used for highly efficient large‐area flexible oganic light‐emitting diodes (OLEDs) remain elusive. In this study, a large‐area fabrication of uniform transparent electrodes for high‐performance flexible OLEDs by exploiting the rapid nanowelding process of silver nanowires (AgNWs) onto polyethylene terephthalate substrate under Xe‐lamp irradiation and mechanical pressing treatment is reported. The performance of AgNWs FTCEs is significantly enhanced by applying the Xe‐lamp beam irradiation for 5 s and subsequent compression at 20 MPa for 15 s, achieving a low sheet resistance of 26.5 Ω sq−1, a high transmittance of 95.2% (at 550 nm), and very smooth surfaces with root‐mean‐square of 5.4 nm. Meanwhile, the nanowelded AgNWs FTCEs maintain excellent electrical conductivity (only a 2.96% increase in ΔR/R0) after 1000 bending cycles. The resulting AgNWs FTCEs‐based green phosphorescent OLED achieves an unprecedented external quantum efficiency (EQE) of 23.7% and a current efficiency as high as 81.5 cd A−1. Benefiting from the uniform properties for resulting AgNWs FTCEs, the fabricated flexible OLED with a large area of 25 × 25 mm2 still retains a high EQE of 22.2% and a current efficiency of 78.0 cd A−1. [ABSTRACT FROM AUTHOR]

Published
2024
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21. Preparation of TiO 2 /SnO 2 Electron Transport Layer for Performance Enhancement of All-Inorganic Perovskite Solar Cells Using Electron Beam Evaporation at Low Temperature.

Author

Xue, Tao, Li, Ting, Chen, Dandan, Wang, Xiao, Guo, Kunping, Wang, Qiang, and Zhang, Fanghui

Subjects
ELECTRON transport, SOLAR cells, ELECTRON beams, CHARGE carriers, TITANIUM dioxide, PEROVSKITE
Abstract

SnO2 has attracted much attention due to its low-temperature synthesis (ca. 140 °C), high electron mobility, and low-cost manufacturing. However, lattice mismatch and oxygen vacancies at the SnO2/CsPbI3−xBrx interface generally lead to undesirable nonradiative recombination in optoelectronic devices. The traditional TiO2 used as the electron transport layer (ETL) for all-inorganic perovskite solar cells (PSCs) requires high-temperature sintering and crystallization, which are not suitable for the promising flexible PSCs and tandem solar cells, raising concerns about surface defects and device uniformity. To address these challenges, we present a bilayer ETL consisting of a SnO2 layer using electron beam evaporation and a TiO2 layer through the hydrothermal method, resulting in an enhanced performance of the perovskite solar cell. The bilayer device exhibits an improved power conversion efficiency of 11.48% compared to the single-layer device (8.09%). The average fill factor of the bilayer electron transport layer is approximately 15% higher compared to the single-layer electron transport layer. Through a systematic investigation of the use of ETL for CsPb3−xBrx PSCs on optical and electronic properties, we demonstrate that the SnO2/TiO2 is an efficient bilayer ETL for PSCs as it significantly enhances the charge extraction capability, suppresses carrier recombination at the ETL/perovskite interface, facilitates efficient photogenerated carrier separation and transport, and provides high current density and reduced hysteresis. [ABSTRACT FROM AUTHOR]

Published
2023
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22. High-Efficiency Metal-Insulator-Metal Electron Emitter Based on Porous Alumina Film

Author

Xue, Tao, Li, Ting, Wang, Xiao, Guo, Kunping, Wei, Guodong, and Liu, Chunliang

Abstract

Vacuum nanoelectronic devices demand efficient electron emission sources, which is increasingly crucial as devices become smaller and more integrated. We propose a Rapid Thermal Treatment method for Metal-Insulator-Metal electron source insulation layers. Samples were treated at 200°C, 300°C, and 400°C in a nitrogen environment. As a result of thermal treatment, the defects in the dielectric layer decreased, and discontinuous islands emerged on the insulating layer’s surface, which increased local electron strength and decreased the electron emission threshold voltage. Consequently, the electron emission efficiency reached 23.6%.

Published
2023
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26. Molecular Encapsulation of Naphthalene Diimide (NDI) Based π‐Conjugated Polymers: A Tool for Understanding Photoluminescence

Author

Royakkers, Jeroen, primary, Guo, Kunping, additional, Toolan, Daniel T. W., additional, Feng, Liang‐Wen, additional, Minotto, Alessandro, additional, Congrave, Daniel G., additional, Danowska, Magda, additional, Zeng, Weixuan, additional, Bond, Andrew D., additional, Al‐Hashimi, Mohammed, additional, Marks, Tobin J., additional, Facchetti, Antonio, additional, Cacialli, Franco, additional, and Bronstein, Hugo, additional

Published
2021
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30. Lanthanide-Induced Photoluminescence in Lead-Free Cs2AgBiBr6 Bulk Perovskite: Insights from Optical and Theoretical Investigations

Author

Schmitz, Fabian, primary, Guo, Kunping, additional, Horn, Jonas, additional, Sorrentino, Roberto, additional, Conforto, Gioele, additional, Lamberti, Francesco, additional, Brescia, Rosaria, additional, Drago, Filippo, additional, Prato, Mirko, additional, He, Zhubing, additional, Giovanella, Umberto, additional, Cacialli, Franco, additional, Schlettwein, Derck, additional, Meggiolaro, Daniele, additional, and Gatti, Teresa, additional

Published
2020
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31. Simulation of Transient Delay Time in Organic LEDs and Application for Signal Transmission

Author

魏 斌 Wei Bin, 郭坤平 Guo Kunping, 司长峰 Si Chang-feng, 彭翠云 Peng Cui-yun, 胡湛晗 Hu Zhan-han, 陈 果 Chen Guo, and 潘赛虎 Pan Sai-hu

Subjects
Radiation, Materials science, business.industry, OLED, Optoelectronics, Transient (oscillation), Condensed Matter Physics, business, Electronic, Optical and Magnetic Materials, Delay time
Published
2017

34. Highly efficient and foldable top-emission organic light-emitting diodes based on Ag-nanoparticles modified graphite electrode

Author

Wang, Shuanglong, primary, Yang, Jiali, additional, Xu, Tao, additional, Dou, Dehai, additional, Tang, Zhenyu, additional, Gao, Zhixiang, additional, Chen, Minyu, additional, Guo, Kunping, additional, Yu, Junsheng, additional, Plain, Jérôme, additional, Bachelot, Renaud, additional, Zhang, Jianhua, additional, and Wei, Bin, additional

Published
2019
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35. Switching the resistive memory behavior from binary to ternary logic via subtle polymer donor and molecular acceptor design.

Author

Pan, Saihu, Zhu, Zhiqiang, Yu, Hang, Lan, Weixia, Wei, Bin, and Guo, Kunping

Abstract

Emerging organic resistive switching memory (ORSM) devices, in which active organic materials possess at least two stable resistance states have attracted considerable attention for their intriguing nonvolatile memory properties. Herein, solution-processed binary ORSM devices incorporating polymer donors (D) of poly(N-vinylcarbazole) (PVK) and small molecular acceptors (A) of 1,3-bis[2-(4-tert-butylphenyl)-1,3,4-oxadiazo-5-yl]benzene (OXD-7) were first investigated. By varying the blending concentration of OXD-7, we demonstrated concentration-dependent resistance switching. To further mediate the memory characteristics, acceptors of both OXD-7 and butylphenyl-5-(4-biphenylyl)-1,3,4-oxadiazole (PBD) were incorporated into PVK donors to form a D–A–A system. The 6 wt% PBD-based ORSM device presented ternary resistive memory characteristics with well-separated current ratios of 1 : 10 : 104 between "OFF", "ON1" and "ON2" states, while three conductivity states held for 104 s as a function of the time. To unveil the resistive switching mechanism of non-volatile memories, a detailed analysis of electrical properties and intertrap charge transfer in D–A and D–A–A systems was also performed. [ABSTRACT FROM AUTHOR]

Published
2021
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44. Iridium(iii) complexes bearing oxadiazol-substituted amide ligands: color tuning and application in highly efficient phosphorescent organic light-emitting diodes

Author

Zhang, Fuli, primary, Si, Changfeng, additional, Dong, Xiaobin, additional, Wei, Donghui, additional, Yang, Xin, additional, Guo, Kunping, additional, Wei, Bin, additional, Li, Zhongyi, additional, Zhang, Chi, additional, Li, Suzhi, additional, Zhai, Bin, additional, and Cao, Guangxiu, additional

Published
2017
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48. High-Performance Organic Photovoltaics Using Solution-Processed Graphene Oxide

Author

田正浩 Tian Zhenghao, 潘赛虎 Pan Sai-hu, 屈文山 Qu Wenshan, 司长峰 Si Chang-feng, 魏斌 Wei Bin, 徐韬 Xu Tao, 高志翔 Gao Zhixiang, and 郭坤平 Guo Kunping

Subjects
chemistry.chemical_compound, Materials science, chemistry, Organic solar cell, Graphene, law, Oxide, Nanotechnology, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Solution processed, law.invention
Published
2017

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