Rare-Earth Doped MAPbBr ₃ :RE (RE = Yb, Eu, Tb) Single Crystals for γ-Ray Detectors

Rare-earth (RE) doping has proven to be effective in enhancing the luminescent and optoelectronic properties of halide perovskites (HPs). However, the growth of RE-doped halide perovskite single crystals remains challenging. Herein, we successfully synthesized nine distinct MAPbBr3:RE (RE = Yb, Eu, Tb) single crystals (6–8 mm in size, RE/Pb = 0.008–0.053%) through systematic optimization of RE reagents, growth temperature, and solution concentration. Structural and optical characterization revealed RE-induced lattice expansion and band gap modulation, confirming the effective incorporation into the perovskite lattice. Furthermore, RE doping significantly improved the charge transport properties of MAPbBr3 single crystals. After doping Yb into MAPbBr3 (Yb/Pb = 0.013%), the trap density decreased from 9.2 × 109 to 2.5 × 109/cm3, carrier mobility increased from 59 to 799 cm2/(V s), and carrier lifetime increased from 199 to 2766 ns. These enhancements translated to exceptional γ-ray detection performance, with the energy resolution (ER) value for 241Am (59.5 keV) improved from 11.0% (for pristine MAPbBr3) to 6.3% (MAPbBr3:Yb) under a 5 V bias. This work not only establishes RE doping as a powerful strategy for optimizing the properties of halide perovskite semiconductors but also opens new avenues for the development of advanced radiation sensing materials.