Zn-doped CdS/CdSe as efficient strategy to enhance the photovoltaic performance of quantum dot sensitized solar cells

•A transition metal Zn-doped CdS/CdSe QDSSCs are performed by SILAR.•The narrowed band gap caused the strong light absorbance.•The high concentration carriers promoted the shift of Fermi level towards the CB.•Zn-doping contributes to attenuation of the interfacial charge recombination rate and prolongs the electron lifetime.