High-performance amphoteric polymer coated lead-free halide perovskite composites: synthesis and application

Lead halide perovskites hold great promise for a wide range of applications owing to their exceptional characteristics. Nevertheless, the inherent toxicity of lead and poor stability concerns considerably restrict their real-world use. Although lead-free halide perovskites reduce toxicity, they experience a substantial decrease in photoluminescence quantum yield (PLQY). To tackle these challenges, Cs₃Cu₂I₅ nanocrystals (NCs) were initially synthesized via a one-step ultrasonic method, followed by the use of amphoteric polymer polyethylene glycol-polycaprolactone (PEG-PCL) to coat the Cs₃Cu₂I₅ NCs, resulting in Cs₃Cu₂I₅/PEG-PCL composites that exhibited a remarkable improvement in stability and PLQY (~ 74.7%). Several characterization techniques were utilized to confirm the successful formation of the perovskite composites and explore the reasons for its high performance. The enhancement in PLQY may be primarily attributed to the passivation effect of PEG on the perovskite. The synthesized composites were then employed for the construction of a highly sensitive fluorescence sensor for H₂S detection, achieving a detection limit as low as 0.70 µmol/L. This study not only offers a novel strategy for enhancing the PLQY of lead-free halide perovskite materials but also demonstrates their promising application in food analysis.