Crystallization optimization enables the high-quality perovskite single crystals towards enhanced photodetection

Organic–inorganic halide perovskites have emerged as promising candidates for high-performance photodetection. However, growing high-quality large-size single crystals via the inverse temperature crystallization (ITC) method remains challenging due to uncontrolled nucleation and defect formation. In this work, the acetylcholine bromide is introduced as an organic additive to improve the crystal quality of the MAPbBr 3 single crystals (SCs). Acetylcholine bromide dissociates into acetylcholine ions, which coordinate with Pb 2+ and Br − via coordination and electrostatic interactions, thereby slowing deposition and improving crystal quality. The as-prepared SCs show enhanced crystallinity, reduced defect density and extended carrier lifetime. The photodetectors based on these crystals achieve an outstanding on/off ratio as high as 2.97 × 10 4 under 5 V bias voltage and 11.7 mW/cm 2 optical power density. Furthermore, the X-ray detectors showed a notably higher μτ of 2.76 × 10 −2 cm 2 V −1 , indicating enhanced charge collection efficiency and significant potential for high-sensitivity radiation detection. This work offers new ideas for ligand design, and provide an effective route for fabricating high-performance perovskite-based optoelectronic devices.