Eye-readable gasochromic and optical hydrogen gas sensor based on CuS–Pd

Abstract

Hydrogen gas sensing is a crucial issue in various hydrogen related areas due to its explosive nature. Here, we report an efficient gasochromic and optical hydrogen sensor based on an ultrathin layer of copper sulfide (CuS) incorporated with palladium (Pd). When exposed to hydrogen environment, the CuS–Pd film changes its color from dark green to brown, which makes the proposed CuS–Pd an eye-readable sensor that circumvents the need for electronics, optic fibers and transducers or electrical readouts. CuS–Pd can also be used as an optical sensor by taking the advantage of decrease in the localized surface plasmon resonance in infrared region due to a reduction in the free carrier density of the CuS valence band upon exposure to H₂ gas. The proposed CuS–Pd optical sensor can efficiently detect the presence of upto 0.8% of H₂ gas in air. Thus, CuS–Pd can be integrated into small size fiber optic devices as an emerging new class of high-performance hydrogen gas sensors.