Conversion efficiency enhancement of CdS quantum dot-sensitized electrospun nanostructured TiO2 solar cells by organic dipole treatment

• CdS QDs were deposited on electrospun TiO2 by the SILAR technique.
• Dipole treatment of the TiO2–CdS composite by an organic dipole.
• Dipole treatment enhanced the efficiency of the TiO2–CdS solar cell by ~100% compared to the non-treated cells.
• The increase in photovoltaic performance was attributed to the upward shifting of CdS QDs' energy levels due to dipole treatment.

Here we fabricated quantum dot-sensitized solar cells (QDSCs) based on electrospinning of unique TiO2 nanostructures and subsequent CdS QDs deposition via successive ionic layer adsorption and reaction (SILAR) followed by dipole treatment (DT). It was found that by treating with 4-methoxy benzenethiol for 24 h, an overall conversion efficiency of 1.17% was achieved under AM1.5 illumination which corresponds to a dramatic 100% enhancement compared with that of untreated cells. The significant photovoltaic improvement was attributed to the upward shifting of CdS QDs energy levels for efficient charge separation and effective electron transport in electrospun TiO2 nanostructures which is confirmed by electrochemical impedance spectroscopy.

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