Not until recently have metal-free halide perovskites become recognized as novel candidates for ferroelectrics and X-ray detection. However, molecular self-assembly of these perovskites and its influence remain unexplored. Here, we prepare large high-quality DABCO-NH₄X₃ (DABCO = N-N′-diazabicyclo[2.2.2]octonium, X = Cl, Br, I) single crystals and demonstrate the understandings of how halide-modulated molecular assembly affects their crystal packing, band nature, mechanical and electrical properties, and final optoelectronic performance. In this series, the 1D crystal packing and low carrier effective masses endow superior in-plane charge transport for the I-based crystal. As such, higher carrier mobility (110 versus ∼10–20 cm² V⁻¹ s⁻¹) and longer charge diffusion length (∼90 versus ∼50 μm) are achieved in contrast to the Cl- and Br-based analogs. The excellent charge transport properties finally translate to highly efficient X-ray detection and imaging for the I-based crystal detector, with a sensitivity up to 567 μC Gy_air⁻¹ cm⁻² and a well-defined “heart” X-ray image.

直到最近，无金属卤化物钙钛矿才被公认为铁电体和 X 射线检测的新候选者。然而，这些钙钛矿的分子自组装及其影响仍未得到探索。在这里，我们制备了大型高质量 DABCO-NH ₄ X ₃ (DABCO = NN' -二氮杂双环 [2.2.2] octonium, X = Cl, Br, I) 单晶，并展示了对卤化物调制的分子组装如何影响的理解它们的晶体堆积、能带性质、机械和电气性能以及最终的光电性能。在该系列中，一维晶体堆积和低载流子有效质量赋予 I 基晶体优异的面内电荷传输。因此，更高的载流子迁移率（110 vs ∼10–20 cm ² V^-1 s ^-1 ) 和更长的电荷扩散长度（~90 对~50 μm）与基于 Cl 和 Br 的类似物形成对比。优异的电荷传输特性最终转化为基于 I 的晶体探测器的高效 X 射线探测和成像，灵敏度高达 567 μC Gy_空气^-1 cm ^-2和明确定义的“心脏”X 射线图像.