Incident photon-to-current conversion efficiency (IPCE) of CdS based quantum dot sensitized solar cells (QDSCs) is a major drawback in their low efficiency. Here we report a new trend in fabrication of QDSC with enhanced IPCE with application of as prepared Ag2S and Ag2S@ZnS QDs as a co sensitizer. Ag2S and Ag2S@ZnS QDs were synthesized first using a microwave method and were examined by means of XRD, TEM and UV–Vis spectroscopy. Then the prepared QDs were applied for the fabrication of QDSCs using a novel drop casting method. The results revealed a significant enhancement of IPCE as well as short current density (12.5 mA·cm−2) and cell efficiency (3%). The enhancement is directly related to well absorption of Ag2S with low band gap in the visible range and effective injection of photo-excited electrons to CdS compact layer according to suggested band diagram. Ag2S@ZnS co-sensitizer showed an enhancement in photocurrent density due to successful passivation of Ag2S QDs and suppressing recombination on their surface.
