Photoelectrochemical Sensor for H 2 S Based on a Lead-Free Perovskite/Metal-Organic Framework Composite.

Halide perovskites have emerged as a highly promising class of photoelectric materials. However, the application of lead-based perovskites has been hindered by their toxicity and relatively weak stability. In this work, a composite material comprising a lead-free perovskite cesium copper iodide (CsCu 2 I 3 ) nanocrystal and a metal-organic framework (MOF-801) has been synthesized through an in situ growth approach. The resulting composite material, denoted as CsCu 2 I 3 /MOF-801, demonstrates outstanding stability and exceptional optoelectronic characteristics. MOF-801 may serve a dual role by acting as a protective barrier between CsCu 2 I 3 nanocrystals and the external environment, as well as promoting the efficient transfer of photogenerated charge carriers, thereby mitigating their recombination. Consequently, CsCu 2 I 3 /MOF-801 demonstrates its utility by providing both stability and a notably high initial photocurrent. Leveraging the inherent reactivity between H 2 S and the composite material, which results in the formation of Cu 2 S and structural alteration, an exceptionally sensitive photoelectrochemical sensor for H 2 S detection has been designed. This sensor exhibits a linear detection range spanning from 0.005 to 100 μM with a remarkable detection limit of 1.67 nM, rendering it highly suitable for precise quantification of H 2 S in rat brains. This eco-friendly sensor significantly broadens the application horizon of perovskite materials and lays a robust foundation for their future commercialization.