Stable precursor engineering for large and high-quality MAPbBr3 single crystal toward efficient high-energy radiation detection
Methylammonium lead tribromide (MAPbBr3) single crystals (SCs) are promising for room-temperature gamma-ray and X-ray detection, but scaling their size often compromises crystal quality. Here, we report a strategic precursor stoichiometry engineering approach to grow inch-sized, high-quality MAPbBr3 SCs via a constant-temperature evaporation method. We show that constructing a robust electrical double layer through organic cation modulation effectively stabilizes the colloidal precursor. This is achieved by synergistically suppressing MA+ deprotonation while promoting MA+ adsorption as counterions on the [PbBrn]2−n complexes, which collectively strengthens interparticle repulsion and raises the nucleation barrier. This multifaceted approach yields MAPbBr3 SCs with lateral dimensions up to 2 inches and an exceptional X-ray diffraction rocking curve full width at half maximum (FWHM) of 0.0093° at the (002) face. Consequently, the SCs enable spectroscopic-grade gamma-ray detection, achieving energy resolutions (ER) of 8.4% for the 57Co source (122 keV) and 11.1% for the 137Cs source (662 keV), along with a high X-ray sensitivity of 1.65 × 10^4 μC Gy−1 cm−2. This work paves the way for the practical application of MAPbBr3 SCs in high-performance gamma-ray and X-ray detection.