Halide-dependent humidity sensing of Cs2SnX6 (X = Cl, Br, I) perovskites for real-time human physiological moisture detection

Lead-free halide perovskites Cs 2 SnX 6 (X = Cl, Br, I) exhibit favorable humidity sensing with a response sequence of Cs 2 SnCl 6 > Cs 2 SnBr 6 > Cs 2 SnI 6 , enabling great potential for real-time non-contact human breath and finger monitoring.