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Enhancing Perovskite Solar Cell Performance through Femtosecond Laser Polishing
摘要： Nonradiative recombination loss is a key process that determines the performance of perovskite solar cells, and how to control it is significant for the research and development of perovskites. Generally, traditional chemical modification/passivation methods are complicated and prone to secondary contamination. Here, we demonstrate femtosecond (fs) laser polishing as a promising technique to ameliorate the surface of perovskite films, to reduce nonradiative recombination loss and improve solar cell performance. The high-intensity fs laser pulses can remove around 20-nm thick perovskite top-layer through ionization process, help to decrease the grain boundary density and enlarge the grain size of perovskite films after recrystallization. We believe that fs laser polishing is a time-effective and highly precise technique which is suitable for large-scaled device production, thus will trigger more applications in optoelectronics.
关键词： femtosecond lasers,perovskites,recombination,passivation,solar cells
更新于2025-09-23 15:21:01
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A passivation mechanism exploiting surface dipoles affords high-performance perovskite solar cells
摘要： The employment of 2D perovskites is a promising approach to tackle the stability and voltage issues inherent in perovskite solar cells. It remains unclear however whether other perovskites with different dimensionalities have the same effect on efficiency and stability. Here, we report the use of quasi-3D azetidinium lead iodide (AzPbI3) as a secondary layer on top of the primary 3D perovskite film that results in significant improvements in the photovoltaic parameters. Remarkably, utilization of AzPbI3 leads to a new passivation mechanism due to the presence of surface dipoles resulting in a power conversion efficiency (PCE) of 22.4 %. The open-circuit voltage obtained is as high as 1.18 V, which is among the highest reported to date for single junction perovskite solar cells, corresponding to a voltage deficit of 0.37 V for a bandgap of 1.55 eV.
关键词： Perovskites,dipoles,work function,surface passivation,solar cells
更新于2025-09-23 15:21:01
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Ambient air-processed mesoscopic solar cells based on methylammonium and phenethylammonium quasi-2D/3D perovskites
摘要： The instability of perovskite solar cells under ambient conditions leads many scientific groups to produce their solar cell devices under controllable, yet, expensive conditions. In this work, a mesoscopic solar cell device produced under ambient air/temperature conditions and relatively high humidity is presented. The active material is based on methylamine, phenethylamine, lead(II) iodide and lead(II) chloride. Furthermore, a bis(trifluoromethane)sulfonimide lithium (Li-TFSI) salt layer was used as a dopant onto mesoscopic TiO2, while the hole-transport material used was the popular poly(3-hexylthiophene-2,5-diyl) (P3HT) polymer. All layers were deposited by simple spin coating technique, while the whole process took place under 40–60% relative humidity–ambient conditions. The sequential deposited perovskite layer was built by a 3D mixed halide (CH3NH3)3PbI3Cl2 layer on top of a mixed 3D/Quasi-2D perovskite (CH3NH3)3PbI3Cl2–(C8H9NH3)2(CH3NH3)2Pb3I10 layer. These specific perovskites were used to take advantage of the well-known power conversion efficiency (PCE) of the mixed halide perovskite based on methylamine, and the proven reproducibility and stability of the phenethylamine-based perovskites, especially under non-controllable conditions. The champion mesoscopic device presented a PCE of 13.22%, with short circuit current density (JSC) of 23.67 mA/cm2, open circuit voltage (VOC) of 1034 mV and fill factor (FF) 0.54.
关键词： Mesoscopic structure,Methylamine–phenethylamine mixed cations,Hybrid organic–inorganic semiconductors,Ambient conditions,Perovskites,Mesoporous solar cells
更新于2025-09-23 15:21:01
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Ultra-High Vacuum Annealing-Assisted Quantum Wells Dimensional Tailoring for Perovskite Light-Emitting Diodes Efficiency Enhancement
摘要： Quasi-two-dimensional (Q-2D) perovskites featured with multiple dimensional quantum wells (QWs) have been the main candidates for optoelectronic applications. However, the excessive low-dimensional perovskite is unfavorable to the device efficiency due to the phonon-exciton interaction and the inclusion of insulating large organic cation. Herein, the low-dimensional QWs formation is suppressed by removing the organic cation 1-naphthylmethylamine iodide (NMAI) through the ultra-high vacuum (UHV) annealing. The perovskite light-emitting diodes (PLEDs) devices based on films annealed with optimized UHV conditions show higher external quantum efficiency of 13.0% and wall-plug efficiency of 11.1% compared to otherwise identical devices with films annealed in a glovebox.
关键词： quantum wells,ultra-high vacuum annealing,dimensional tailoring,quasi-two-dimensional perovskites,perovskite light-emitting diodes
更新于2025-09-23 15:21:01
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Dual-site mixed layer-structured FA <sub/>x</sub> Cs <sub/>3a??x</sub> Sb <sub/>2</sub> I <sub/>6</sub> Cl <sub/>3</sub> Pb-free metal halide perovskite solar cells
摘要： Structure engineering of trivalent metal halide perovskites (MHPs) such as A3Sb2X9 (A ? a monovalent cation such as methyl ammonium (MA), cesium (Cs), and formamidinium (FA) and X ? a halogen such as I, Br, and Cl) is of great interest because a two dimensional (2D) layer structure with direct bandgap has narrower bandgap energy than a zero dimensional (0D) dimer structure with indirect bandgap. Here, we demonstrated 2D layer structured FACs2Sb2I6Cl3 MHP by dual-site (A and X site) mixing. Thanks to the lattice-symmetry change by I–Cl mixed halide, the shortest ionic radius of Cs, and the lower solution energy due to dual-site mixing, the FACs2Sb2I6Cl3 MHP had 2D layer structure and thereby the MHP solar cells exhibited improved short-circuit current density.
关键词： metal halide perovskites,2D layer structure,bandgap engineering,dual-site mixing,solar cells
更新于2025-09-23 15:21:01
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Enhancing the performance of LARP-synthesized CsPbBr <sub/>3</sub> nanocrystal LEDs by employing a dual hole injection layer
摘要： Lead halide perovskites have been considered promising materials for optoelectronic applications owing to their superior properties. CsPbBr3 nanocrystals (NCs) with a narrow particle size distribution and a narrow emission spectrum are synthesized by ligand-assisted re-precipitation (LARP), a low-cost and facile process. In inverted CsPbBr3 NC LEDs, a dual hole injection layer (HIL) of 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile (HAT-CN)/MoO3 is introduced to enhance hole injection and transport, because HAT-CN can extract electrons easily from the hole transport layer and leave a large number of holes there. The current and power efficiencies of the optimized device with a dual HIL are 1.5- and 1.8-fold higher than those of the single HIL device. It is believed that the dual HAT-CN/MoO3 HIL effectively promotes hole injection and has promise for application in many other devices.
关键词： Ligand-assisted re-precipitation,Optoelectronic applications,Lead halide perovskites,CsPbBr3 nanocrystals,Dual hole injection layer,HAT-CN/MoO3
更新于2025-09-23 15:21:01
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Integrating Properties Modification in the Synthesis of Metal Halide Perovskites
摘要： Metal halide perovskites have attracted enormous attention and show huge potential as promising building blocks of next-generation optoelectronic devices owing to their unique optical and electrical properties. For further promoting their practical applications in various fields, the synthesis of metal halide perovskites with desired characteristics is essential to satisfy the requirements of their applications. The properties of perovskites are highly related to their crystal structures and chemical compositions. The optoelectronic properties of perovskites can be altered via decreasing their dimensionality owing to the quantum confinement effect, while enlarging the crystal size of perovskite can promote the construction of device arrays with homogenous performance. In addition, modifying the chemical composition of perovskites via alloying, doping, or controlling vacancies also greatly changes their optical and electrical properties. Thus, integrating the properties modification in the synthesis process of metal halide perovskites can not only improve the productivity of the desired perovskites but also provide a great opportunity to prepare designed crystals with predictable features. The exciting progress in the synthesis of metal halide perovskites with controllably tailored properties is summarized herein. It is hoped that these technologies can promote the development of perovskites.
关键词： properties modification,metal halide perovskites,synthesis integrating
更新于2025-09-23 15:21:01
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Manganese doping stabilizes perovskite light-emitting diodes by reducing ion migration
摘要： Lead halide perovskite light-emitting diodes have recently emerged as high-performance devices. However, they degrade rapidly. This degradation has been attributed to the mixed ionic-electronic nature of these perovskites. Manganese doping increases the stability of perovskite light-emitting diodes, but the effects of manganese doping on ion migration are not well understood. We use impedance spectroscopy and transient ion-drift measurements to study the effect of manganese doping on ion migration in PEABr0.2Cs0.4MA0.6PbBr3 quasi-bulk 2D/3D perovskite light-emitting diodes. We find that manganese doping enhances the activation energy for ion migration two fold and reduces the diffusion coefficient. These changes in the behavior of mobile ions help to explain the improved stability in perovskite light-emitting diodes upon manganese doping and lead to a better understanding of the influence of passivating agents on ion migration and thus on the stability of the devices.
关键词： capacitance,perovskites,manganese,mobile ions,transient ion drift,impedance,light-emitting diodes
更新于2025-09-23 15:21:01
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Energetics and Energy Loss in 2D Ruddlesdena??Popper Perovskite Solar Cells
摘要： 2D Ruddlesden–Popper perovskites (RPPs) are emerging as potential challengers to their 3D counterpart due to superior stability and competitive efficiency. However, the fundamental questions on energetics of the 2D RPPs are not well understood. Here, the energetics at (PEA)2(MA)n?1PbnI3n+1/[6,6]-phenyl-C61-butyric acid methyl ester (PCBM) interfaces with varying n values of 1, 3, 5, 40, and ∞ are systematically investigated. It is found that n–n junctions form at the 2D RPP interfaces (n = 3, 5, and 40), instead of p–n junctions in the pure 2D and 3D scenarios (n = 1 and ∞). The potential gradient across phenethylammonium iodide ligands that significantly decreases surface work function, promotes separation of the photogenerated charge carriers with electron transferring from perovskite crystal to ligand at the interface, reducing charge recombination, which contributes to the smallest energy loss and the highest open-circuit voltage (Voc) in the perovskite solar cells (PSCs) based on the 2D RPP (n = 5)/PCBM. The mechanism is further verified by inserting a thin 2D RPP capping layer between pure 3D perovskite and PCBM in PSCs, causing the Voc to evidently increase by 94 mV. Capacitance–voltage measurements with Mott–Schottky analysis demonstrate that such Voc improvement is attributed to the enhanced potential at the interface.
关键词： energy loss,2D Ruddlesden–Popper perovskites,open-circuit voltage,perovskite solar cells,energetics
更新于2025-09-23 15:21:01
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Mn-doped 2D Sn-based perovskites with energy transfer from self-trapped excitons to dopants for warm white light-emitting diodes
摘要： Mn-doped 2D perovskite powders are promising phosphors for warm white light-emitting diodes (LEDs). However, it remains a challenge to solve the problem of lead toxicity and improve photoluminescence quantum yields (PLQYs). Here, we have successfully prepared Mn-doped 2D Sn-based perovskite materials ((C8H17NH2)2Sn1-xMnxBr4). The PLQYs of (C8H17NH2)2Sn1-xMnxBr4 (x = 0.26) powders reach up to 42%. The as-prepared (C8H17NH2)2Sn1-xMnxBr4 exhibit a single broad photoluminescence (PL) band, differing from the dual peaks of Mn-doped lead halide perovskite quantum dots. Theoretical conclusions and experimental results show the competitive relationship between self-trapped excitons (STEs) emission from the host crystal and dopant Mn d-d transition emission. With Mn dopant concentration increasing, the PL spectra exhibit red shifts and the full width at half-maximum (FWHM) turns larger, which is constructive for warm white LEDs. The fabricated warm white LEDs based on (C8H17NH2)2Sn1-xMnxBr4 show warm white light correlated color temperature (CCT, 3542 K) and high color-rendering index (Ra, 88.12). Our work provides new possibilities for optoelectronic devices based on lead-free perovskite materials.
关键词： self-trapped excitons,Mn-doped,photoluminescence quantum yields,2D Sn-based perovskites,warm white light-emitting diodes
更新于2025-09-23 15:21:01