Electrodeposited ZnO thin film as an efficient alternative blocking layer for TiCl4 pre-treatment in TiO2-based dye sensitized solar cells

•Exploiting of electrodeposited ZnO blocking layer as an alternative of the TiCl4 pre-treatment process at photoanode.•Utilizing PVA as cluster capping agent in deposition solution to control the growth and crystallization of ZnO NPs.•Using EIS for investigation of blocking layer interface behavior such as electron transfer/transport resistance.•The results demonstrated the significant enhancement of the electron lifetime and cell performance.

Recently, ZnO nanostructures have received considerable attention in fabrication of dye sensitized solar cell (DSSC) photoanodes due to their unique transport properties. In the present study, a chronoamperometric method was performed to fabricate the ZnO nanostructures as an appropriate alternative of TiCl4 pre-treatment to reduce the recombination reactions, while retaining the TiO2-based DSSC performance. The effect of polyvinyl alcohol (PVA) on ZnO electrodeposition to control the growth and crystallization of ZnO nanostructures was investigated. ZnO/TiO2 based-DSSCs were fabricated using N719 ruthenium dye and all photovoltaic parameters were characterized. Incident photon to current efficiency (IPCE), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and VOC decay techniques were employed for studying the cell properties which is resulted in a significant enhancement in cell performance.

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