Zero-Dimensional Lead-Free Perovskite Single Crystals for High-Performance Photodetection

The rapid development of optoelectronic technologies has placed ever-increasing demands on high-performance photodetectors, as the intrinsic properties of the active materials fundamentally determine the detection limit and operational stability. Although organic–inorganic hybrid perovskites exhibit superior optoelectronic properties, lead-based perovskites suffer from the drawbacks of heavy-metal toxicity and poor structural stability, which severely limit their practical applications. Low-dimensional lead-free perovskite single crystals have therefore emerged as a promising material system, owing to their extremely low defect density, grain-boundary-free nature, and strong intrinsic stability. Here, high-quality 0D lead-free MA3Sb2I9 single crystals were grown via a seed-induced two-step crystallization method, and photodetectors based on these single crystals were fabricated. The resulting photodetector exhibits a high responsivity of 22.77 A/W, an external quantum efficiency (EQE) of 6971.92%, and a specific detectivity of 1.49 × 1012 Jones. Notably, stable photoresponse was maintained over ~450 on/off switching cycles, evidencing excellent operational repeatability and long-term stability. These results highlight the great potential of MA3Sb2I9 single crystals as a stable, lead-free candidates for high-performance photodetection.