Metal halide perovskites:A rising platform for gas sensing?

Sensing gases and volatile organic compounds is a highly requested ability in large economic fields, such as the food industry, agriculture, and health care. Depending on the foreseen specific application, electronic noses have to be sensitive, selective, highly reliable, and also robust and cheap. However, it is undoubted that rarely all these characteristics are met simultaneously and for every analyte. The current technology makes large use of metal oxide semiconductors, which exhibit many limitations, for example, in their selectivity and the need for very high temperatures to lower activation energies and reach high sensitivity [A. Dey, Mater. Sci. Eng., B 229, 206 (2018)]. This opens to investigations of further material platforms that may provide enhanced performance. Metal halide perovskites have shown a high sensitivity toward their environment, and the first gas-sensing behavior at room temperature was already demonstrated in 2016 [Fang et al., Sci. Adv. 2(7), e1600534 (2016)]. Recent reports show the huge potential of metal halide perovskites sensors for multiple gases and volatile organic compounds. Here, we will summarize what has been demonstrated until now with a metal halide perovskite and related system. We will discuss the physical mechanisms, which is the basis of sensing, and if these mechanisms have the potential to allow the development of sensors that are highly sensitive, selective, and efficient. Furthermore, we will conclude by giving a prospect for the future of gas sensors based on metal halide perovskites.