Enhanced photoelectric performance of rutile SnO2 by charge compensation effects modulated by Sb and N

The electronic structure of Sb-N co-doped SnO2 was explored by first principles calculation. The results show that Sb (donor) and N (acceptor) introduce new energy levels in the band gap, which reduce the band gap of SnO2 obviously. Besides, the carrier separation rate of the system is improved owing to the charge compensation effect of Sb and N. Consequently, the photoelectric performance of SnO2 is improved. Based on the results of theoretical calculation, the intrinsic and different ratios of Sb-N co-doped SnO2 were prepared by hydrothermal method. And the samples were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), and x-ray photoelectron spectroscopy (XPS). The photoelectric performance of the prepared intrinsic and Sb-N co-doped SnO2 electrodes was studied. The results prove that all samples are rutile phase with the dopants Sb and N entered into SnO2 lattice by substituting Sn and O. Besides, the 5% co-doped sample has uniform spherical shape and dispersed character. The photoelectric performance tests indicate that photoelectric performance of SnO2 is enhanced by Sb-N co-doping. The maximum photocurrent value (9 μA/cm2) and minimum electrochemical impedance is achieved at the doping ratio of 5%. Theoretical calculation and experiment results indicate that Sb-N co-doped SnO2 possesses superior photoelectric performance.