Enhancing the Performance of Perovskite Environmental Sensors through the Synergistic Effect of the Natural Antioxidant

All-inorganic perovskite CsPbX3 is considered to be the next-generation optical material due to its excellent optical properties and potential applications in optoelectronics. However, the inherent ionic crystal property makes it susceptible to interaction with moisture and oxygen in the ambient atmosphere and hinders the development of stable perovskite devices. Herein, a natural and nontoxic molecule, ascorbic acid (AA), is introduced to improve the performance of perovskite nanocrystals. Experimental results reveal that the strong coordination between carbonyl groups and undercoordinated Pb2+, together with the hydrogen bonding interaction between hydroxyl groups and defects of halide ions in AA, suppress nonradiative recombination. In addition, with the synergistic effect of the C═O and –OH groups in AA, the perovskite crystal structure exhibits excellent stability due to hydrogen bonding. Finally, the demonstration of humidity sensing based on perovskites has been presented. It is shown that the humidity sensor exhibits good sensitivity in the range of 30%–80% relative humidity, with a detection limit of 3.9% and a response time of 46 s. This work provides a low-cost, nontoxic, and efficient modification approach and demonstrates an easy way to improve the performance and humidity stability of perovskite.