Fabrication of Cd-Doped TiO2 Nanorod Arrays and Photovoltaic Property in Perovskite Solar Cell

Cadmium-doped TiO2 nanorods arrays were directly grown on transparent conductive substrates without seeds layer via a facile method and applied in perovskite solar cell. The morphology was examined by field emission scanning electron microscopy (FESEM) and the structure was examined by X-ray powder diffraction (XRD). SEM showed that the Cd-doped TiO2 nanorods had a length of 520 nm and a diameter of 80 nm. Energy dispersive spectrometer (EDS) and Tauc plot spectra showed that Cd was successfully doped and changed TiO2 band gap from 3.05 to 3.03 eV. The flat band potential of the Cd-doped TiO2 show negative deviation of similar to 30 mV and lead to an increment of V-oc of solar cell when compared with undoped sample. Cd-doped TiO2 nanorods also showed a higher diffuse reflection than the un-doped TiO2 nanorods under visible light. Electrochemical impedance spectroscopy showed that the resistance of the device based on Cd-doped TiO2 nanorods was lower than that of the undoped device. The PCE of Cd-doped perovskite device achieved 8.30%, which was almost 30% higher than that of the undoped TiO2. (C) 2016 Elsevier Ltd. All rights reserved.