Halide Perovskite Single Crystals: Optoelectronic Applications and Strategical Approaches

Abstract

Halide perovskite is one of the most promising semiconducting materials in a variety of fields such as solar cells, photodetectors, and light-emitting diodes. Lead halide perovskite single crystals featuring long diffusion length, high carrier mobility, large light absorption coefficient and low defect density, have been attracting increasing attention. Fundamental study of the intrinsic nature keeps revealing the superior optoelectrical properties of perovskite single crystals over their polycrystalline thin film counterparts, but to date, the device performance lags behind. The best power conversion efficiency (PCE) of single crystal-based solar cells is 21.9%, falling behind that of polycrystalline thin film solar cells (25.2%). The oversized thickness, defective surfaces, and difficulties in depositing functional layers, hinder the application of halide perovskite single crystals in optoelectronic devices. Efforts have been made to synthesize large-area single crystalline thin films directly on conductive substrates and apply defect engineering approaches to improve the surface properties. This review starts from a comprehensive introduction of the optoelectrical properties of perovskite single crystals. Then, the synthesis methods for high-quality bulk crystals and single-crystalline thin films are introduced and compared, followed by a systematic review of their optoelectronic applications including solar cells, photodetectors, and X-ray detectors. The challenges and strategical approaches for high-performance applications are summarized at the end with a brief outlook on future work.

Self‐Assembled Perovskite Nanoislands on CH3NH3PbI3 Cuboid Single Crystals by Energetic Surface Engineering

“…Our single crystals show superior carrier mobility to thin‐film counterparts [ 24 ] and are comparable to high‐quality single crystals. [ 11a,25 ] In short, TPC measurement confirms that CsI treatment can help cuboid SCs achieve higher carrier mobility, for which 60% improvement is realized by 65 nm of CsI treatment (from 56 to 93 cm 2 V −1 s −1 ).…”

“…There have been numerous efforts to refine the surface states, which have frequently been employed for perovskite polycrystalline films. [ 11 ] For instance, the solution‐processable surface engineering to passivate the defective sites on the PSCs could be an effective approach to draw forth the enhanced device performance. [ 10a ] However, it is still challenging to form the homogeneously passivated surfaces on the PSCs due to the presence of the rough surface morphology with chemically nonuniform surface states, established on the PSCs during the crystal growth process.…”

Impact of Cesium Concentration on Optoelectronic Properties of Metal Halide Perovskites

“…Metal halide perovskites attract considerable attention due to their remarkable properties revealing potential applications in optoelectronic devices such as solar cells [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ], photodetectors [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ], light emitting diodes [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. They have also been used for photocatalysts [ 35 ] and bioimaging [ 36 ].…”

A Centrifugal‐Force‐Assisted Wet‐Etching Approach toward Top‐Down Fabrication of Perovskite‐Single‐Crystalline Thin Films

“…However, the defective grain boundaries in perovskite polycrystalline films inevitably cause carrier recombination loss and deteriorate the device performance [5] . In contrast, perovskite‐single‐crystalline thin films show distinctive advantages because they have no grain boundaries thereby greatly reducing the trap density and show higher carrier mobility, longer carrier lifetime, and longer diffusion length [6–12] . Currently, there are two main methods for preparing perovskite‐single‐crystalline thin films: bottom‐up method and top‐down method.…”