Lead-Free Perovskite\nNanocrystals Decorating Graphene\nfor Detecting Nerve Agents

Highly toxic chemical compounds known as chemical warfare\nagents\n(CWAs) present substantial threats to human health and safety. Their\nswift detection and identification play a critical role in preventing\nexposure and ensuring timely intervention. This work develops nanohybrids\nto detect dimethyl methylphosphonate (DMMP), a simulant gas for sarin\ncompound, which is classified as a nerve agent. Specifically, two\ndifferent compositions (Cs<sub>3</sub>Cu<sub>2</sub>Br<sub>5</sub> and Cs<sub>2</sub>AgBiBr<sub>6</sub>) of lead-free perovskite nanocrystals\n(NCs) have been employed to decorate graphene. The sensitive films\nexhibit remarkable sensitivity to DMMP at the ppb range and under\nambient temperature conditions. It is worth mentioning that this work\nreports for the first time the successful use of perovskite NCs for\ndetecting DMMP. Besides, the sensing performance of both perovskites\nhas been compared, revealing that Cs<sub>3</sub>Cu<sub>2</sub>Br<sub>5</sub>-decorated graphene outperforms Cs<sub>2</sub>AgBiBr<sub>6</sub>, offering up to a 4-fold improvement. The synthesis and decoration\nprocess are straightforward, industrially scalable, and inexpensive,\nwhile the use of lead-free perovskites leads to an environmentally\nfriendly and harmless approach. These facts linked to a sensitive\nand reversible detection of DMMP at low concentrations pave the way\nfor developing CWA gas sensors based on the use of lead-free perovskite\nNCs.