One-dimensional assembly of TiO2 nanoparticles toward enhancing light harvesting and electron transport for application in dye-sensitized solar cells

Abstract

One-dimensional (1D) assembly of TiO₂ nanoparticles (NPs) was successfully achieved by an improved electrospinning technique. Electrospinning precursor solution was prepared with conventional TiO₂ NPs and polyvinylpyrrolidone dispersed in ethanol. The newly developed 1D assembly of nanoparticles (AS-NP) has been introduced into the photoanode in dye-sensitized solar cells (DSSCs). Compared to the traditional disordered stacking of TiO₂ NPs, the AS-NPs bring in faster charge transport and longer electron lifetime, as well as a higher light scattering ability (especially in the wavelength range from 500 nm to 650 nm). It is exhibited that the AS-NPs can enhance electron transport and light scattering, while retaining the merits of NP morphology. Consequently, the efficiency of a cell based on an AS-NP/NP bilayer photoanode could be improved by about 15% in comparison to a reference cell made of absolute TiO₂ NPs.