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Enhanced On–Off Ratio Photodetectors Based on Lead‐Free Cs 3 Bi 2 I 9 Single Crystal Thin Films
Author(s) -
Li WenGuang,
Wang XuDong,
Liao JinFeng,
Jiang Yong,
Kuang DaiBin
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201909701
Subject(s) - materials science , perovskite (structure) , photodetector , halide , indium tin oxide , optoelectronics , crystallite , thin film , crystallization , electron mobility , single crystal , crystal (programming language) , nanotechnology , chemical engineering , crystallography , inorganic chemistry , chemistry , programming language , computer science , engineering , metallurgy
Hybrid organic–inorganic lead halide perovskite single crystal thin film (SCTF) recently has attracted enormous interest in the field of optoelectronic devices, since it efficiently resolves the trade‐off between thickness and carrier diffusion length. However, the toxicity of lead element and the instability induced by organic component still hinder its future developments. In this work, lead‐free all‐inorganic Cs 3 Bi 2 I 9 SCTF with a high orientation along (00h) has been in situ grown on indium tin oxide (ITO) glass via a space‐limited solvent evaporation crystallization method. The trap density of Cs 3 Bi 2 I 9 SCTF (5.7 × 10 12 cm −3 ) is 263 folds lower than that of the polycrystalline thin film (PCTF) counterpart, together with a 5‐order‐of‐magnitude higher carrier mobility. These superior charge transfer properties enable a photoresponse on–off ratio as high as 11 000, which far surpasses that of the PCTF device by 460 folds, comparable to the lead halide perovskite. Furthermore, the Cs 3 Bi 2 I 9 SCTF photodetector exhibits outstanding stability even without any encapsulation, whose initial performance is well maintained after aging 1000 h in humid air of 50% RH or continuous on–off light illumination for 20 h. This work will pave the way to produce new families of high‐performance, stable, and nontoxic perovskite SCTF for future optoelectronic applications.