Using a CdS under-layer to suppress charge carrier recombination at the Ag2S/FTO interface.

• CdS under-layer reduces the recombination at Ag 2 S/FTO interface. • Photoinduced charge carrier dynamics of FTO/CdS/Ag 2 S has been studied. • CdS under-layer raise 52% PCE of Ag 2 S solar cell. [Display omitted] The recombination of photoinduced charge carriers is detrimental to the photovoltaic performance of solar cells. In this work, we used CdS as an under-layer to reduce the recombination of photoinduced charge carriers at the Ag 2 S/FTO (F-doped SnO 2) interface. The CdS under-layer was deposited onto an FTO substrate using a facile chemical bath deposition (CBD) method. By controlling the thickness of the CdS film between Ag 2 S and FTO, the recombination of photoinduced charge carriers was successfully suppressed. The effect of the CdS under-layer on the charge carrier recombination was carefully evaluated by transient surface photovoltage (TSPV) measurements, electrochemical impedance spectroscopy (EIS) and a photoelectrochemical method. The power conversion efficiency (PCE) of solar cell devices with a 40 nm CdS under-layer is 1.16%, which is ~52% enhancement compared to those of FTO/Ag 2 S-based solar cell devices. Our work may provide a useful strategy to suppress photoinduced charge carrier recombination at the electrode and absorber semiconductor interface. [ABSTRACT FROM AUTHOR]