Enhancement of solar cell performance through the formation of a surface dipole on polyacrylonitrile-treated TiO2 photoelectrodes

[Display omitted] The dye-sensitized solar cell with a polyacrylonitrile-treated TiO2 layer showed an enhancement of approximately 17% in terms of its power conversion efficiency (PCE) when compared to that of a reference cell with a bare TiO2 layer. It was found that, by incorporating the polyacrylonitrile onto the surface of the TiO2, a surface dipole was formed, which induced a conduction band edge shift of the TiO2 in a positive direction. This shift led to a considerable improvement in the electron injection efficiency, which explained the increased PCE. •A surface dipole was formed on the TiO2 surface by incorporating polyacrylonitrile (PAN).•The surface dipole led to a conduction band edge shift of the TiO2 in a positive direction.•The Jsc was increased by the significant enhancement of the electron injection efficiency.•A performance enhancement of 17% was achieved via the PAN modification of the TiO2 surface. Polyacrylonitrile (PAN) was adsorbed onto the TiO2 surface, and the resulting photoelectrodes were applied in dye-sensitized solar cells (DSSCs). The DSSC with the PAN-modified TiO2 showed an increase in its short-circuit current (Jsc) and a decrease in its open-circuit voltage (Voc), resulting in a 17% enhancement of its photovoltaic performance when compared to the reference cell. By incorporating PAN onto the surface of the TiO2, a surface dipole was formed, which induced a conduction band edge shift of the TiO2 in a positive direction. This shift led to a considerable improvement in the electron injection efficiency, and hence the Jsc.