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A stimuli‐responsive multiple chirality switching material, which can regulate opposed chiral absorption characteristics, has great application value in the fields of optical modulation, information storage and encryption, etc. However, due to the rareness of effective functional systems and the complexity of material structures, developing this type of material remains an insurmountable challenge. Herein, a smart polymer film with multiple chirality inversion properties was fabricated efficiently based on a newly‐designed acid & base‐sensitive dye‐grafted helical polymer. Benefited from the cooperative effects of various weak interactions (hydrogen bonds, electrostatic interaction, etc.) under the aggregated state, this polymer film exhibited a promising acid & base‐driven multiple chirality inversion property containing record switchable chiral states (up to five while the solution showed three‐state switching) and good reversibility. The creative exploration of such a multiple chirality switching material can not only promote the application progress of current chiroptical regulation technology, but also provide a significant guidance for the design and synthesis of future smart chiroptical switching materials and devices. [ABSTRACT FROM AUTHOR]

Quasi‐2D perovskites light‐emitting diodes (PeLEDs) have achieved significant progress due to their superior optical and electronic properties. However, the blue PeLEDs still exist inefficient energy transfer and electroluminescence performance caused by mixed multidimensional phase distribution. In this work, transition metal salt (zinc bromide, ZnBr2) is introduced to modulate phase distributions by suppressing the nucleation of high n phase perovskites, which effectively shortens the energy transfer path for blue emission. Moreover, ZnBr2 also facilitates energy level matching and reduces non‐radiative recombination, thus improving electroluminescence (EL) efficiency. Benefiting from these combined improvements, an efficient blue PeLEDs is obtained with a maximum external quantum efficiency (EQE) of 16.2% peaking located at 486 nm. This work provides a promising approach to tune phase distribution of quasi‐2D perovskites and achieving highly efficient blue PeLEDs. [ABSTRACT FROM AUTHOR]

The morphological characteristics of in‐situ‐grown perovskite thin films are strongly influenced by the interface properties of previous layer. Additionally, their photoelectric characteristics are closely tied to the formed defects during the solution‐processing film for the oxidized tin ions, which significantly hinders the practicality of tin‐based perovskites in near‐infrared light‐emitting diodes (LEDs). Here, formamidine thiocyanate is employed to modify the interfacial behaviors of hole transport layer under the perovskite layer, resulting in reduced contact angle, improved surface wettability, enhancement of the crystallinity and film quality of tin‐based perovskite. Furthermore, by introducing guanidine thiocyanate into the precursor solution, the oxidation is successfully suppressed during the film formation of tin‐based perovskite, thereby reducing film defects to suppress non‐radiative recombination. A near‐infrared LEDs with a maximum external quantum efficiency reached 5.1%, representing a twofold improvement compared to unmodified devices. This advancement holds significant implications for the progression of tin‐based near‐infrared light emission technology. [ABSTRACT FROM AUTHOR]

Functional materials that exhibit circularly polarized luminescence (CPL) have shown immense potential in applications such as 3D optical displays and advanced information encryption. However, facile and efficient regulation of the multiple emission properties in chiral systems has remained a challenge due to the scarcity of suitable materials and the complexity of the systems. Herein, a multiple CPL regulation platform is fabricated by the helical co‐assembly of an aldehyde‐functionalized fluorane dye (Rhodol‐CHO, 6′‐(diethylamino)‐3′‐hydroxy‐3‐oxo‐3H‐spiro[isobenzofuran‐1,9′‐xanthene]‐4′‐carbaldehyde) and chiral liquid crystals, which can efficiently combine multiple stimuli‐responsive characteristics and high optical activity. By introducing acid, base, and compounds containing primary amino (─NH2) groups, the CPL property of the system can be easily modified. The obtained CPL systems exhibit apparent asymmetry, with glum values reaching 0.54–0.75). Further, these CPL modules are successfully applied in multi‐mode information encryption, highlighting their practical utility. Therefore, this study presents a novel strategy for developing materials with diverse CPL behaviors based on a simple‐designed platform, advancing further applications of CPL materials. [ABSTRACT FROM AUTHOR]

Perovskite light‐emitting diodes (PeLEDs) based on quasi‐2D perovskites have attracted great attention in the past few years. Although significant achievements are made in device performance, fabrication of high‐efficiency PeLEDs with pure‐red (620–635 nm) light emission remains a significant challenge, which inhibits their practical application for full‐color displays. Herein, a series of efficient red PeLEDs at 625 nm are realized by employing volatile alkylammonium chlorides (propylammonium chloride) passivators. The interaction of PbI2 with propylamine (PA)...H+Cl− in the precursor solution effectively passivates the defects, leading to reduced non‐radiative recombination and enhanced device performance. By optimizing the amount of PACl, an external quantum efficiency (EQE) of 16.1% and a maximum brightness of 1701 cd m−2 are achieved, among the best‐performing quasi‐2D I‐based PeLEDs with emissions ranging from 620 to 635 nm. This work provides a new route to improve the stability and efficiency of pure‐red PeLEDs. [ABSTRACT FROM AUTHOR]

The n‐type quantum dot (QD) active layer is the core component of lead sulfide QD solar cells (PbS QDSCs). In the state‐of‐the‐art PbS QDSCs, the active layer is commonly obtained through liquid‐phase ligand exchange (LPLE). Due to the intricate chemical state of the ligand exchange solution providing halide ligand, therefore, the PbS‐OAQD solutions is used at concentrations of 20, 30, and 40 mg mL−1 for LPLE, aiming to investigate the reasons for different surface states post‐exchange and their impact on device performance. The results indicate that when the concentration of the PbS‐OA QD solution is 30 mg mL−1, the exchanged QDs exhibit complete removal of surface OA, a higher content of short‐chain ligand PbX2 (X = I, Br), Consequently, devices fabricated using PbS‐PbX2 QD obtained through the exchange of 30 mg mL−1 PbS‐OA QD solution achieve a higher power conversion efficiency (PCE) of 12.53%. This study presents a simple and effective strategy to enhance the performance of PbS QDSCs. [ABSTRACT FROM AUTHOR]

Inorganic perovskite quantum dots (QDs) have garnered significant attention due to their outstanding optical properties. However, perovskite quantum dot light‐emitting diodes (Pe‐QLEDs) still face challenges related to their fluorescence efficiency and electron injection. First, the electron transport layer (ETL) leads to severe non‐radiative recombination due to fluorescence quenching in CsPbI3 QDs. Second, there is an electron injection imbalance resulting from low electron injection efficiency, leading to reduced non‐radiative recombination and external quantum efficiency. To address these issues, this study introduces two interface layer materials with different electron affinities, 1,3,5‐Tris(3‐pyridyl‐3‐phenyl)benzene (TmPyPB) and 2,4,6‐Tris(3′‐(pyridine‐3‐yl)biphenyl‐3‐yl)‐1,3,5‐triazine (TmPPPyTz). These materials not only passivated defects on the surface of CsPbI3 QDs films but also effectively prevented the fluorescence quenching of CsPbI3 QDs by the PO‐T2T (ETL). TmPPPyTz, with a relatively lower LUMO energy level, further improved energy level matching, significantly enhancing electron injection efficiency. Ultimately, using interface engineering with the TmPPPyTz interface layer, the devices achieved an outstanding 25.80% champion‐level external quantum efficiency (EQE) for Pe‐QLEDs with only a sub‐bandgap voltage of 1.7 V and half‐life (T50) is 17.99 h at 100 nits. This research provided an effective method to enhance the performance of CsPbI3 Pe‐QLEDs, addressing long‐standing issues inhibiting their efficiency. [ABSTRACT FROM AUTHOR]

Perovskite nanocrystals for light‐emitting diodes are often synthesized by uncontrollable metathesis reactions, suffering from low product yield, nonuniform growth, and poor stability. Herein, by controlling the nucleation kinetics with high dissociation constant (Ka or Kb) acids or bases, homogenous one‐route nucleation of perovskite nanocrystals is achieved as the cluster intermediates are eliminated. The stable, shape uniform, and narrow size distribution green nanocrystals are synthesized. The perovskite nanocrystal film exhibites excellent stability in 80% humidity air with only a 10% photoluminescence intensity drop after 16 h. Efficient and stable electroluminescence is demonstrated with an FWHM of 16 nm at 517 nm. The green devices shows a peak EQE of 24.13% with a lifetime T50 of 54 min at 10 000 cd m−2. [ABSTRACT FROM AUTHOR]

The quality of the tin dioxide interface has an important impact on the performance of perovskite solar cells. Herein, a facile potassium acetate strategy to effectively treat the SnO2/perovskite interface and enhance the film quality of perovskite crystals is used. The defect density at the interface can be reduced, thereby suppressing the nonradiative recombination of excitons. Enhanced performance of the two‐step deposited perovskite device is obtained with an open‐circuit voltage (VOC) of 1.173 V, a fill factor of 78.31%, and a power conversion efficiency of 23.63%. [ABSTRACT FROM AUTHOR]

The electrical properties of hole transport layers (HTL) are critical factors for the high performance of lead sulfide quantum dot solar cells (PbS CQDSCs). Herein, the impacts of doping the organic HTL PTB7‐Th with lithium bis(trifluoromethanesulfonimide) (LiTSFI) on the performance of quantum dot solar cells are explored and a notable enhancement in the fill factor is observed. A series of analytical characterizations of the doped HTLs are performed and it is found that doping with LiTFSI significantly deepens the Fermi level of the HTL, thereby improving the charge separation ability within the devices. Additionally, the conductivity of doped HTL is also improved. By optimizing the doping conditions, the doped device achieves a maximum power conversion efficiency of 12.68%. This doping strategy of organic HTL promotes the development of lead sulfide quantum dot solar cell techniques. [ABSTRACT FROM AUTHOR]

Enhancing the absorption of incident light and promoting the effective separation of carriers are two effective strategies to improve the power conversion efficiency of lead sulfide quantum dots (PbS CQDs) solar cells. Herein, a simple solution spin‐coating method to synthesize a novel ZnO electron transport layer with a wrinkled surface structure is developed. ZnO‐wrinkled surface structure can enhance the absorption of PbS CQDs solar cells in the range of 600–1000 nm compared with the normal planar ZnO film, leading to the enhancement in the short‐current density. Further, by combining the wrinkled and planar ZnO to form a bilayer ZnO, the energy band alignment between ZnO and PbS CQDs is more suitable for the carrier transmission. Finally, PbS CQDs solar cell based on the bilayer ZnO yields a champion efficiency of up to 13.5%, presenting almost 10% enhancement compared to that based on the single planner ZnO. This method provides a simple and cost‐effective method to enhance the efficiency of PbS CQDs thin‐film solar cells. [ABSTRACT FROM AUTHOR]

Although organic metal halide perovskite light‐emitting diodes (PeLEDs) have been developed rapidly in recent years, their commercialization and further applications are still hindered by ion migration‐induced inferior operational stability. Although the formation of a quasi‐2D structure is a well‐known solution that can efficiently suppress ion migration, the operation lifetime improvement is still limited. In this study, long‐chain phenylbutanammonium is used to replace the commonly used phenethylammonium as the L‐site cations. With large steric hindrance, ion migration inside the PeLEDs is effectively suppressed. Consequently, the PeLED with near‐infrared emission at 763 nm exhibited an operational lifetime (T90) of up to 5.3 h, which is 53‐fold higher than that of the control device. This study demonstrates the feasibility of significant stability improvement using a simple cation engineering strategy for PeLEDs. [ABSTRACT FROM AUTHOR]

This document is a technical paper titled "Efficient Perovskite quantum dots Light Emitting Diodes." It discusses the use of CsPbI3 perovskite quantum dots (QDs) in light-emitting diodes (LEDs) and the challenges faced in their practical applications. The paper presents a new strategy of proton-prompted short-chain ligand exchange in the synthesis of CsPbI3 QDs and the design of interface layers with high electron affinity. These approaches result in improved device performance, with a champion-level external quantum efficiency (EQE) of 25.80% achieved. This study represents the highest reported performance for pure red perovskite quantum dot LEDs to date. [Extracted from the article]

Poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hole injection layer plays an important role in planar Si/PEDOT:PSS heterojunction solar cells (HSCs). Herein, a MoOx mixed aqueous PEDOT:PSS cosolvent is developed and is applied into a Si/PEDOT:PSS solar cell preparation via a time‐saving one‐step spin‐coating method. With an optimal concentration of MoOx dopants, the power conversion efficiency of the device exhibits from 10.26% up to 13.82% with all inherent photovoltaic parameters enhanced. The detailed characterization and analytical results indicate that an advanced electronic property is produced by MoOx dopants and interface optimization caused by synergistic effects from Mo5+ and Mo6+ species with PEDOT:PSS, which enhances its interface work function and promotes hole transportation capacity. The result paves a path for exploring efficient Si/PEDOT:PSS HSCs with suitable functional material and a simple solution‐processable method. [ABSTRACT FROM AUTHOR]

The efficiency roll-off in blue phosphorescent organic light emitting diodes (OLEDs) using different carbazole compounds as the host is systematically studied. While there is no significant difference in device efficiency, OLEDs using ter-carbazole as the host show a reduction in efficiency roll-off at high luminance. Data from transient photoluminescence and electroluminescence measurements show that the lower triplet-triplet annihilation (TTA) and triplet-polaron quenching (TPQ) rates in devices with the ter-carbazole host compared with other carbazole hosts are the reasons for this reduced efficiency roll-off. It is also found that the host materials with low glass transition temperatures are more susceptible to the efficiency roll-off problem. [ABSTRACT FROM AUTHOR]

Recent progress has been reported regarding high color gamut blue QDs development, improvement of QLEDs performance including efficiency and lifetime, and development of printable QD inks and ink-jet printing technique of QLEDs, in order to solve those key challenges towards QLED display technology commercialization. [ABSTRACT FROM AUTHOR]

Smart materials with circularly polarized luminescence (CPL) tunable ability show great potential for advanced information storage and encryption. While an effective integration of high photoluminescence quantum yield (PLQY) and facile regulation of CPL property in thin films are of great significance, it is challenging due to the scarcity of suitable materials and complexity of systems. Herein, a novel acid‐responsive CPL tunable molecule is designed by combining an aggregation‐induced emission (AIE) component (TPE), an acid‐responsive luminophore (Rhodol), and a chiral aniline. Benefitting by the “AIE” effect of TPE and acid‐sensitive nature of Rhodol, the acidified molecule (S‐Rhodol‐TPE) exhibits a high PLQY even when doped in the polymer substrate at high concentrations. In addition, due to the fluorescence resonance energy transfer (FRET) process between TPE and Rhodol, the emission color of S‐Rhodol‐TPE can be easily regulated by the doped ratio and acidified degree of S‐Rhodol‐TPE in the polymer film. This work exhibits a unique approach to achieving smart CPL‐tunable films with high PLQYs and multiple emission color‐regulation properties, which can undoubtedly facilitate the progress of CPL tunable materials. [ABSTRACT FROM AUTHOR]

Guangdong Juhua has fabricated the world's first 31 inch, 4K, H‐QLED TV, by using ink‐jet printing technology. The Red and Green pixel of H‐QLED TV is made from electrical luminescence quantum dot (QD for short) materials, and Blue pixel is made from soluble blue OLED material. It is a self‐emitting and top emission display with excellent performance brought by quantum dot materials, which provide large colour gamut, wider view angle, high luminance and high resolution. [ABSTRACT FROM AUTHOR]

23.1: Invited Paper: High efficiency and Stability of Ink-jet Printed Quantum Dot Light Emitting Diodes via Dual Ionic Surface Passivation. Here, ink-jet printed quantum dots LEDs with an external quantum efficiency over 16% and half lifetime of more than 1,721,000 hours, were reported for the first time. And the performance from ink-jet printed QLEDs truly opens the gate of quantum dots LED application for industry. [Extracted from the article]

Alloying the metal halide perovskite composition has become a key strategy for engineering the optoelectronic properties for various applications. However, the difference in complexation between ions poses a threat to crystal stability. In particular, the phase segregation in wide‐bandgap perovskites (WBG) with mixed halides is the major challenge in multi‐junction photovoltaic devices. Here, a systematic study is reported on the origin of phase segregation in a prototypical mixed halide perovskite (MHP) MAPbI2Br. It is found that the crystallinity and surface morphology are not associated with the lattice stability. Using highly sensitive external quantum efficiency (s‐EQE) measurement, it is found that the defects in the MHP are mainly associated with the Pb2+ and I−/Br− ions. Consistently, density‐function‐theory (DFT) calculation confirms that the MAPbI2Br surface is dominated by the metal‐halide components, and the imbalanced surface charge is responsible for the lattice instability. The role of physical and chemical passivation approaches in MHP is further investigated. The former limits the ion migration and allows dissociated ions to recover to their corresponding defective sites, whereas the latter lowers the surface energy by neutralizing the charge density on the lattice surface. This work brings insight into the phase segregation and passivation mechanisms in MHP. [ABSTRACT FROM AUTHOR]

We fabricated OLEDs on corrugated high-refractive-index substrates. With a macro lens to extract the substrate mode, we were able to achieve an EQE of 63.2%. The high efficiency was achieved by suppressing the thin film guided modes and efficiently extracting the surface plasmon mode with the corrugated structure. [ABSTRACT FROM AUTHOR]