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.