Laser‐Assisted Synthesis of Ag₂S‐Quantum‐Dot‐in‐Perovskite Matrix and Its Application in Broadband Photodetectors

Abstract Halide perovskites are widely explored as efficient photoresponsive materials for optoelectronic devices. However, understanding and controlling their underlying optical and electrical properties remains limited. Here, a novel approach is developed by introducing silver sulfide (Ag₂S) quantum dots (QDs) into an MAPbBr₃ single crystal. The high‐quality Ag₂S‐quantum‐dot‐in‐perovskite (Ag₂S‐QDiP) matrixes synthesized through a laser‐assisted inverse temperature crystallization (LA‐ITC) strategy show broadband light‐sensitive wavelength from 550 to over 1000 nm, and a balanced carriers mobility facilitates their transmission and collection. A Ag₂S‐QDiP‐enabled photodetector is demonstrated, which exhibits considerably enhanced responsivity and detectivity of 1.17 A W⁻¹ and 6.24 × 10¹⁴ Jones at 532 nm, and 57.69 mA W⁻¹ and 1.03 × 10¹¹ Jones at 1064 nm, respectively. The enhanced performance in the near‐infrared (NIR) region can be attributed to the discrete heterojunction formed between MAPbBr₃ and Ag₂S QDs, which enhances the light absorption in the NIR range and facilitates photogenerated excitons’ separation at the interface. The facile synthesis process, the more balanced transport behavior, and the ensuing improved device performance highlight introducing QDs into perovskite single crystal as an efficient strategy for tuning fundamental properties of perovskite and for developing high‐efficiency broadband electronic and optoelectronic devices.