Enhanced charge generation and transfer performance of the conical bamboo-like TiO2 nanotube arrays photo-electrodes in quantum dot sensitized solar cells

•Conical bamboo-like TiO2 NTs have been prepared by different anodization process.•The optical absorption and electron-hole separation property of photo-electrodes have been enhanced.•More paths and high rate of charge transfer have been enhanced by the conical bamboo-like TiO2 NTs structure.•Conical bamboo-like TiO2 NTs based CuInS2 QDSSCs exhibits photovoltaic efficiency from 4.65% to 5.98%.