Three-dimensional flower-like rutile TiO2 microsphere composed of nanorods: a potential material as light scattering layer for DSSCs

Abstract

The low spectrum utilization and the recombination of photo-generated electrons are the main challenges for improving the performance of dye sensitized solar cells(DSSCs). In this article, a three-dimensional flower-like rutile titanium dioxide(TDF-TiO2) was successfully synthesized via a simple sol-thermal process. X-Ray diffraction patterns(XRD) and scan electron microscopy(SEM) images exhibit that the TDF-TiO2 are the rutile TiO2 microsphere composed of lots of regular cuboid nanorods. Applying this TDF-TiO2 as light scattering layer on the photoanode of DSSCs, the devices present an excellent photovoltage performance, yielding a power conversion efficiency(PCE) of 7.69%, which can be mainly attributed to the enhanced light utilization and the reduced recombination of pho-to-generated electrons upon a combined analysis of electrochemical impedance spectroscopy(EIS), open-circuit vol-tage decay(OCVD), and intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage spec-troscopy(IMPS/IMVS), etc. As a conclusion, TDF-TiO2 is a potential material as light scattering layer and optical transition medium to improve the performance of DSSCs, and this work further demonstrated that regulating the morphology and particle size of TiO2 is an efficient approach for enhancing the performance of DSSCs by optimizing the utilization of light and the transporting behaviors of photo-generated electrons.