Enhanced charge generation and transfer properties on anatase nanodendrite array photo-electrodes for high-efficiency quantum dot sensitized solar cells

Abstract

The loading amount of quantum dots and trap density are the significant issues for quantum dot sensitized solar cells. Anatase TiO2 nanodendrite array is employed as the photo-electrodes for the CuInS2 quantum dot sensitized solar cells instead of the traditional TiO2 nanowire array, which is prepared by two-step hydrothermal process. The excellent charge generation and charge separation properties have been exhibited by the CuInS2 quantum dots sensitized photo-electrodes based on the anatase TiO2 nanodendrite array, which are characterized by the optical absorption spectra and photoluminescence spectra. Meanwhile, the branches from anatase TiO2 nanodendrite array provide much more paths for charge transfer and reduce the charge recombination traps in photo-electrodes, which have provided excellent charge transfer property for the solar cells. As a result, higher current density can be obtained by anatase TiO2 nanodendrite array structure based CuInS2 quantum dot sensitized solar cells, which has exhibited the photovoltaic conversion efficiency enhancement from 4.7% to 5.48%.