Nano-crystalline thin and nano-particulate thick TiO2 layer: Cost effective sequential deposition and study on dye sensitized solar cell characteristics

•Thin TiO2 layer is deposited on conducting substrate using sol–gel based dip coating.•TiO2 nano-particles are synthesized using hydrothermal route.•Thick TiO2 particulate layer is deposited on prepared thin layer.•Dye sensitized solar cells are made using thin and thick layer based photo-anode.•Introduction of thin layer in particulate photo-anode improves the cell efficiency.

A compact thin TiO2 passivation layer is introduced between the mesoporous TiO2 nano-particulate layer and the conducting glass substrate to prepare photo-anode for dye-sensitized solar cell (DSSC). In order to understand the effect of passivation layer, other two DSSCs are also developed separately using TiO2 nano-particulate and compact thin film based photo-anodes. Nano-particles are prepared using hydrothermal synthesis route and the compact passivation layer is prepared by simply dip coating the precursor sol prepared through wet chemical route. The TiO2 compact layer and the nano-particles are characterised in terms of their micro-structural features and phase formation behavior. It is found that introduction of a compact TiO2 layer in between the mesoporous TiO2 nano-particulate layer and the conducting substrate improves the solar to electric conversion efficiency of the fabricated cell. The dense thin passivation layer is supposed to enhance the photo-excited electron transfer and prevent the recombination of photo-excited electrons.

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