Solar diode sensor: Sensing mechanism and applications

► Autonomous gas sensor with self-generated signal solely driven by solar light. ► Based on a diode (n-ZnO/p-Si) and gas sensing unit (CdS@n-ZnO) in a singular heterostructure. ► Capable of quantitatively detecting oxidizing and reducing gases. ► Novel sensing mechanism verified by ON/OFF gas sensing and gas-dependent C-V measurements.