Low-Temperature Operable Nitric Oxide Sensor Based on Solution-Processed Cs2PdBr6 Perovskite Nanoparticles

Nitric oxide (NO) detection is vital for environmental monitoring and medical diagnostics, yet conventional metal oxide gas sensors generally require high operating temperatures.Here, we report a low-temperature NO sensor based on inorganic halide perovskite Cs₂PdBr₆ nanoparticles synthesized via a mild, solution-based wet-chemical route followed by antisolvent crystallization.The antisolvent process effectively reduced the particle size to several tens of nanometers, enabling a distinct and reversible sensing response to NO even at 100 °C.The sensor exhibited good linearity in the concentration range of 10-150 ppm, a detection limit of 9.25 ppm, and excellent selectivity over interfering gases such as CO and ethanol.Density functional theory calculations indicate that NO preferentially adsorbs onto Pd sites on the Cs₂PdBr₆ surface and behaves as an electron donor, leading to a decrease in the resistance of n-type Cs₂PdBr₆.These results demonstrate that antisolvent-processed Cs₂PdBr₆ is a promising material for energy-efficient and selective NO sensing.