Lead-Free Perovskite Nanocrystals Decorating Graphene for Detecting Nerve Agents

Highly toxic chemical compounds known as chemical warfare agents (CWAs) present substantial threats to human health and safety. Their swift detection and identification play a critical role in preventing exposure and ensuring timely intervention. This work develops nanohybrids to detect dimethyl methylphosphonate (DMMP), a simulant gas for sarin compound, which is classified as a nerve agent. Specifically, two different compositions (Cs3Cu2Br5 and Cs2AgBiBr6) of lead-free perovskite nanocrystals (NCs) have been employed to decorate graphene. The sensitive films exhibit remarkable sensitivity to DMMP at the ppb range and under ambient temperature conditions. It is worth mentioning that this work reports for the first time the successful use of perovskite NCs for detecting DMMP. Besides, the sensing performance of both perovskites has been compared, revealing that Cs3Cu2Br5-decorated graphene outperforms Cs2AgBiBr6, offering up to a 4-fold improvement. The synthesis and decoration process are straightforward, industrially scalable, and inexpensive, while the use of lead-free perovskites leads to an environmentally friendly and harmless approach. These facts linked to a sensitive and reversible detection of DMMP at low concentrations pave the way for developing CWA gas sensors based on the use of lead-free perovskite NCs.