Er and Mg co-doped TiO2 nanorod arrays and improvement of photovoltaic property in perovskite solar cell

Abstract Doping metal element on One-dimension (1-D) nanostructure to improve the photoelectric properties of metallic oxides has been widely studied. In this paper, Magnesium (Mg) and Erbium (Er) ions were co-doped onto TiO 2 nanorod arrays (NRAs) via a facile hydrothermal method and applied in perovskite solar cells (PSCs). The synthesized Er/Mg co-doped TiO 2 NRAs was investigated by field emission-scanning electron microscopy (FE-SEM), X-ray powder diffraction (XRD), UV–vis diffused reflectance and electrochemical impedance spectroscopy (EIS). Er/Mg co-doped TiO 2 changed the band gap, which increases the charge injection efficiency. The EIS exhibited that the Er/Mg co-doped device has a higher recombination resistance than un-doped device, which enhances the open circuit voltage (V oc ) of the solar cells. Simultaneously, UV–Vis absorption reflectance spectra show that the co-doped TiO 2 NRAs enhance the light capture ability via absorbing infrared light and increase the short-circuit current (J sc ). The power conversion efficiency (PCE) of Er/Mg co-doped PSC device increased from 8.26% to 9.67%, which was 17% higher than that of the un-doped device. This paper opens a door to single-element doping or multi-element co-doping 1-D nanostructured materials for the improving the utilization of solar energy and the photoelectric conversion performance of PSCs.