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 ABX₃ 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‐NH₄Br₃ (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 DABCO²⁺, 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.

中文翻译：

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无金属卤化物钙钛矿单晶，具有超长的充电寿命，可实现高效的X射线成像。

作为钙钛矿家族中的特殊类别，无金属卤化物钙钛矿最近成为有机铁电体的新型半导体，并有望实现ABX ₃钙钛矿结构的广泛化学多样性，并具有机械柔韧性，轻巧和环保的加工工艺。然而，在17年前的最初发现之后，没有关于其电荷传输性质的实验信息，仅简要提及了它们的光电性质。在此，无金属卤化物钙钛矿DABCO-NH ₄ Br ₃（DABCO = N - N报道了“-二氮杂双环[2.2.2] their”及其表征的内在光学和电子性质以及无金属卤化物钙钛矿光电电子的演示。结果表明，晶体具有异常大的约16 eV的半能隙和特定的能带性质，价带最大和导带最小分别主要由卤化物和DABCO ²⁺支配。异常大的半间隙使接近毫秒状态的超长寿命合理化，从而导致很高的电荷扩散长度（数十微米）。晶体还具有高X射线衰减以及轻巧的特性。所有这些特性可转化为高性能X射线成像，灵敏度高达173μCGy_空气^-1 cm⁻²。这使得不含金属的钙钛矿成为下一代光电子学的新型候选物。