Three‐dimensional hybrid perovskite heterostructure single crystals toward highly efficient x‐ray detectors

Abstract Solution‐based self‐assembled perovskite heterojunction single crystals enable precise modulation of the physical and chemical properties of materials, demonstrating significant potential for optoelectronic applications. However, the directed synthesis of these heterostructures and the underlying mechanism for the enhancement of their optoelectronic performance remain elusive. In this study, we designed and synthesized a three‐dimensional (3D) polar hybrid perovskite heterojunction single crystal, denoted as (MHy) 2 Pb(2)Cl 4 ·Pb(1)Cl 2 ( MPC ), by leveraging the lone‐pair electrons on the terminal N atom of organic cations and their coordination with Pb. Interestingly, MPC exhibits an ordered–ordered structural transition with increasing temperature and an increase in spontaneous polarization reversal. Theoretical calculations reveal that the MPC crystal exhibits configurationally distinct charge carriers: the electron wavefunctions are delocalized across the entire structure, while the hole wavefunctions are confined to the non‐distorted layers. Furthermore, we constructed a high‐performance x‐ray detector based on this single‐crystal heterojunction, which achieved a sensitivity of 11 654 μC·Gy −1 ·cm −2 , surpassing the performance of most reported x‐ray detectors. This work provides valuable insights into the development of heterostructure single crystals and their applications in optoelectronics. image