Unleashing the potential of Ga3+ doped Co2SnO4 thin films for enhanced chemi-resistive traits in dimethylamine gas sensing at room temperature

• Pristine and 1 - 5 wt% Ga 3+ doped Co 2 SnO 4 films were deposited via spray pyrolysis. • Ga 3+ doping boosted chemisorption density and oxygen-vacancy defects in Co 2 SnO 4 film. • The CTOG5 sensor showed enhanced response and strong selectivity toward DMA gas. • The DMA sensor shows strong cross-selectivity and good tolerance to humidity. In light of the growing demand for highly efficient and selective gas sensing technologies toward hazardous amines, we present an enhancement in gas sensing performance by cationic doping strategy. This work reports a chemi-resistive gas sensor designed to detect dimethylamine (DMA) gas at room temperature. Moreover, DMA is a toxic and malodorous compound frequently associated with serious environmental and health concerns. The inverse spinel structure is characterized by a distinct cation distribution across its tetrahedral and octahedral sites. This configuration results in enhanced catalytic activity and a high density of surface-active sites. Consequently, it exhibits superior performance compared to conventional binary metal oxide-based gas sensors. This work highlights the deposition and gas sensing capabilities of pristine and gallium (Ga 3+ ) doped Co 2 SnO 4 thin films prepared using chemical spray pyrolysis under optimized annealing conditions. Subsequently, the sensing layers were characterized through structural, optical, morphological, and elemental analyses, and their gas sensing performance was finally evaluated. By tailoring the cationic composition and microstructure, the 5 Wt. % Ga 3+ doped Co 2 SnO 4 (CTOG5) sensing layer exhibits enhanced selectivity (S = 813), rapid response time (144 s) - recovery time (21 s) dynamics, superior longevity (S = 821) after 90 days, stable repeatability (upto 4 cycles), and excellent cross-selectivity towards 1 ppm of DMA gas at room temperature. The incorporation of dopant facilitates increased active sites and catalytic interaction with target molecules. This approach offers a low power, high performance solution for selective DMA gas sensing in environmental and health related real time applications.