All-inorganic halide perovskite CsPbBr₃: a DFT study of a self-powered formaldehyde sensor

The high surface activity and large specific surface area of metal halide perovskite materials create favorable conditions for improving the sensitivity and selectivity of gas sensors. Meanwhile, the high photoelectric conversion efficiency makes perovskite materials the best candidates for new self-powered gas sensing systems. Therefore, the adsorption mechanism of several volatile organic compounds (VOCs) on CsPbX₃ (X = Cl, Br, and I) surfaces was investigated based on first-principles calculations and the non-equilibrium Green's function, including C₂H₆, CH₄, CH₃OH, and CH₂O. The results show that CsPbBr₃ (CPB) has excellent gas-sensing properties for CH₂O molecules. The current-voltage (I-V) curves indicate that the transport properties of CH₂O after adsorption on the CPB surface had a clear response. Moreover, the good mechanical response makes the adsorption process reversible and provides the possibility for flexible devices. Finally, the good absorption spectrum lays the foundation for the application of CPB in photovoltaic (PV) self-powered sensors. Therefore, we predict that CPB is expected to be a candidate for a CH₂O gas sensor with high sensitivity and selectivity.