Enhanced photoelectric performance of rutile SnO2 by double-hole-assisted coupling of carbon and sulfur

Abstract

Photoelectric performance of (C, S) co-doped SnO2 was explored by an integrated strategy combining first principle calculation with experimental measurement. The exploration began with theoretical calculation upon geometry characteristic and electronic structure of pure and (C, S) co-doped SnO2, then follow by experimental measurement. Namely, pure and different ratios of (C, S) co-doped SnO2 were prepared and characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS). And photoelectric performance of the prepared pure and (C, S) co-doped SnO2 electrodes was studied. Theoretical calculation result indicate that carbon and sulfur atom interact intensely to each other by lattice distortion. Fully filled energy levels are introduced to the top of the valence band, resulting effective reduction of band gap value and suppression of charged defects. Consequently, the photoelectric performance of SnO2 is improved. Double-hole-assisted coupling mechanism of dopants in SnO2 is interpreted to reveal the interaction of C and S. Besides, experimental results indicate that all samples are rutile phase with the dopants carbon and sulfur entered into SnO2 crystal by substituting oxygen. 5% co-doped sample shows the most homogeneous spherical shape and dispersed character, which is provided with the maximum photocurrent value (6.8 μA/cm2) and minimum electrochemical impedance. Theoretical calculation and experiment jointly indicate that (C, S) co-doped SnO2 possess superior photoelectric performance. The doping method of double-hole-assisted coupling may contribute to the design of highly active tin oxide-based photoelectric materials, and also pave the way for modification of other congener materials.