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.