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Metal‐Free Halide Perovskite Single Crystals with Very Long Charge Lifetimes for Efficient X‐ray Imaging
Author(s) -
Song Xin,
Cui Qingyue,
Liu Yucheng,
Xu Zhuo,
Cohen Hagai,
Ma Chuang,
Fan Yuanyuan,
Zhang Yunxia,
Ye Haochen,
Peng Zhanhui,
Li Ruipeng,
Chen Yonghua,
Wang Jianpu,
Sun Huaming,
Yang Zhou,
Liu Zhike,
Yang Zupei,
Huang Wei,
Hodes Gary,
Liu Shengzhong Frank,
Zhao Kui
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202003353
Subject(s) - halide , perovskite (structure) , materials science , charge carrier , metal , crystallography , optoelectronics , inorganic chemistry , chemistry , metallurgy
Metal‐free halide perovskites, as a specific category of the perovskite family, have recently emerged as novel semiconductors for organic ferroelectrics and promise the wide chemical diversity of the ABX 3 perovskite structure with mechanical flexibility, light weight, and eco‐friendly processing. However, after the initial discovery 17 years ago, there has been no experimental information about their charge transport properties and only one brief mention of their optoelectronic properties. Here, growth of large single crystals of metal‐free halide perovskite DABCO‐NH 4 Br 3 (DABCO = N ‐ N ′‐diazabicyclo[2.2.2]octonium) is reported together with characterization of their instrinsic optical and electronic properties and demonstration, of metal‐free halide perovskite optoelectronics. The results reveal that the crystals have an unusually large semigap of ≈16 eV and a specific band nature with the valence band maximum and the conduction band minimum mainly dominated by the halide and DABCO 2+ , respectively. The unusually large semigap rationalizes extremely long lifetimes approaching the millisecond regime, leading to very high charge diffusion lengths (tens of μm). The crystals also exhibit high X‐ray attenuation as well as being lightweight. All these properties translate to high‐performance X‐ray imaging with sensitivity up to 173 μC Gy air −1 cm −2 . This makes metal‐free perovskites novel candidates for the next generation of optoelectronics.