Ultrasonically Exfoliated Nanocrystal-Based Z‑Scheme SnSe2/WSe2 Heterojunction for a Superior Electrochemical Photoresponse

The low-cost facile fabrication of photoanodes with high solar absorption is one of the key factors for efficient photoelectrochemical (PEC) photodetectors. Hereby, we are reporting a liquid-exfoliated nanocrystal-based SnSe2/WSe2 Z-scheme heterojunction (HJ) photoanode for superior self-powered photoelectric conversion. The liquid-exfoliated nanocrystals exhibit nanosized dimensions and a good crystalline nature. X-ray diffraction and Raman spectra confirm the equal contribution of SnSe2 and WSe2 nanocrystals in HJ electrodes. The prepared electrodes are further utilized for the PEC photoresponse with a PEC configuration of FTO/SnSe2@WSe2 HJ/electrolyte/pt. The HJ electrode shows an ∼3 times higher self-powered photoresponse than individual materials by superior visible-light absorption and rapid z-direction charger carrier transfer driven by reducing the recombination rate. Further, we are reporting the electrochemical measurements in the IO3 –/I– redox couple electrolyte to study its dominance on the self-powered PEC photoresponse. The IO3 –/I– mediator significantly enhances the self-powered ability by ∼1.5 times. Moreover, the flexible photodetector based on the Z-scheme SnSe2/WSe2 HJ demonstrated an appreciable self-powered photoresponse at different bending states. The flexible PEC performance with the IO3 –/I– redox couple mediator opens up the future gateway for efficient energy conversion and storage devices.