摘要
In this work, we designed a strategy that combines different organic compounds with TMD layered films to enhance the selectivity for specific volatile organic compounds (VOCs) and increase the overall sensitivity for gas sensor applications. Here, we synthesized a thin tin diselenide (SnSe2) layered thin film using a plasma-assisted chemical vapor reaction (PACVR) followed by drop casting of specific concentrations of organic molecules, including Cysteamine (CA), Mercaptoundecanoic acid (MUA), and Copper(II) phthalocyanine (CuPc), to improve the gas-sensing selectivity and performance of VOCs. The results show that after drop-casting of 5 wt% CuPc on a 10 nm-thick SnSe2 layered thin film (5 wt% CuPc@SnSe2_10 nm), the responses for formaldehyde are six times higher than that of the pristine 10 nm-thick SnSe2 layered thin film under ambient conditions and show excellent selectivity of formaldehyde (HCHO) among the VOCs. First-principles calculations elucidated the enhanced sensing mechanism, demonstrating favorable adsorption energies and distinct charge transfer characteristics for HCHO on CuPc@SnSe2. Furthermore, the 5 wt% CuPc@SnSe2_10 nm sensor displayed good stability, enhanced humidity sensitivity, and robust performance after harsh thermal cycling with unchanged morphology in different temperatures and humidity. These findings underscore the significant potential of CuPc-decorated SnSe2 heterostructures for practical, stable, and high-performance gas sensing applications.
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•SnSe2 films were surface-modified by drop-casting with organic molecules (CA, MUA, and CuPc).•The 5 wt% CuPc@SnSe2_10 nm sensor shows a six times higher response and high selectivity for formaldehyde.•First -principles calculations reveal favorable HCHO adsorption and distinct charge transfer on the CuPc@SnSe2 surface.•The 5 wt% CuPc@SnSe2_10 nm sensor shows high stability and robust performance after harsh thermal cycling and humidity test.