Encapsulation of Cs3Bi2Br9 perovskite photocatalyst with polythiophene for prolonged activity in oxidizing and humid environment

Despite their growing popularity in modern technology, halide perovskites suffer from susceptibility to oxidation, limiting their applications. Our aim was to enhance Cs3Bi2Br9 perovskite's performance in humid environments through polythiophene encapsulation. This extended its lifespan while preserving photocatalytic abilities, as demonstrated in toluene decomposition experiments. We confirmed the stability of Cs3Bi2Br9 encapsulated with polythiophene over four photocatalytic cycles and identified photogenerated electrons and superoxide radicals as key contributors to toluene decomposition. Benzaldehyde was detected as the primary toluene decomposition product, and we observed partial pollutant mineralization, evidenced by increased CO2 concentration after photocatalysis. Additionally, using hybrid ex–situ transmission electron microscopy, we observed delayed oxidation of encapsulated perovskite. Encapsulation hindered, but did not entirely prevent, water vapor penetration into Cs3Bi2Br9 particles. This progress suggests promising prospects for perovskite–based composites retaining photocatalytic capabilities under elevated humidity conditions.