Facile Strategy for Facet Competition Management to Improve the Performance of Perovskite Single-Crystal X-ray Detectors

Methylammonium lead tribromide perovskite single crystals have been demonstrated to be good candidates as sensitive X-ray detectors in direct detection mode in recent years. However, its X-ray detection performance based on the orientation of different facets is still not clear. Here, we developed a facile strategy to chemically expose the [110] facet of single crystals from low-cost solution processes by tailoring the nonstoichiometry of feeding ions to selectively suppress the growth of the [100] facet. In contrast to physically cutting and sawing single-crystal ingots, this avoids damage to the fragile single crystals as well as orientation errors, more suitable for the naturally soft lattice. Compared to the [100] facet, the exposed [110] facet of perovskite single crystals exhibits a smaller trap density and excellent charge carrier transportation properties, leading to an improved sensitivity of 3928.3 μC/Gyair/cm2 to 120 keV hard X-rays, which potentially outperforms the currently dominating CsI scintillator of a commercial digital radiography (DR) medical imager for a routine health check.