Non-Centrosymmetric Chiral Structures for Hybrid Bismuth Halides With Stable Self-Driven X-Ray Detection

Self-driving X-ray detectors have the advantages of low energy consumption, portability, and light weight. However, a complex heterostructure system must be constructed to generate a built-in electric field capable of driving carriers in many scenario. Here, we have pioneered the consideration of spatially breaking the symmetry of crystals, thereby giving them the ability to self-drive carriers, known as the bulk photovoltaic effect (BPVE). Specifically, ( {R}/{S} -MPZ) ^{{2}+} ( {R}/{S} -MPZ ={R}/ S-2-Methylpiperazine) chiral ions were introduced to deinduce the crystallization of ( {R}/{S} -MPZ)BiI5 in the non-centrosymmetric P 2_{{1}} 2_{{1}} 2_{{1}} space group. In this framework, the position of the electron cloud in real space is displaced by X-ray irradiation, resulting in self-driving behavior. As a result, our X-ray detectors exhibit a sensitivity of 54~\mu C Gy _{\text {air}}^{-{1}} cm ^{-{2}} and an ultralow detection limit of 18.4 nGyair s ^{-{1}} under zero bias. ^{^{^{}}} In addition, they feature long-term stability over half a year and impressive imaging performance.