Enhanced photoelectric performance of (2Al, S) co-doped rutile SnO2

Abstract

In this study, theoretical calculations and experiments have been carried out to investigate the photoelectric performance of (2Al, S) co-doped rutile SnO₂. The electronic structures are studied by density functional theory (DFT). It is found that the metal Al can assist the bonding of the incorporated S with the neighboring O in SnO₂, introducing new energy levels in the forbidden band of SnO₂, which enhance the photoelectric performance. Meanwhile, the experiments are conducted to verify this. The (2Al, S) co-doped SnO₂ with different doping ratios are prepared by a hydrothermal method. The samples are characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Results show that all the samples have rutile structure without any extra phase, and the dopant S²⁻ ion was implanted into the crystalline lattice of (2Al, S) co-doped SnO₂ and Al dopants replaced Sn atoms. The photoelectric performance tests show Al and S co-doping can improve the photoelectric performance, especially with a doping ratio of 5%, when the photocurrent reaches maximum of 3.0 μA cm⁻² which is almost twice as much as pure SnO₂, and the impedance is the smallest. The experiments results are consistent with our theoretical calculations. These findings are expected to be helpful for the design of highly active tin oxide-based photoelectric materials.