Novel Au inlaid Zn2SnO4/SnO2 hollow rounded cubes for dye-sensitized solar cells with enhanced photoelectric conversion performance

Abstract

We developed a facile strategy for the fabrication of uniform Au inlaid Zn₂SnO₄/SnO₂ hollow rounded cubes with an adjustable Au loading content using ZnSn(OH)₆ as the precursor, chloroauric acid as the Au source and ascorbic acid as the reducing agent. The Au inlaid Zn₂SnO₄/SnO₂ hollow rounded cubes show enhanced light absorption ability and reduced recombination rate of photogenerated electron–hole pairs compared with pure Zn₂SnO₄/SnO₂. The hollow rounded cube structured Au–Zn₂SnO₄/SnO₂ sample displays a high surface area and high dye adsorption ability. As photoanodes for DSSCs, the Au–Zn₂SnO₄/SnO₂ hollow rounded cubes demonstrate a greatly enhanced J_sc and an improved power conversion efficiency of up to 2.04%, almost 73% higher compared to the photovoltaic conversion efficiency of pure Zn₂SnO₄/SnO₂ based DSSCs. The greatly improved power conversion efficiency of DSSCs based on the Au inlaid Zn₂SnO₄/SnO₂ photoanode can be attributed to the following three factors. Firstly, the localized surface plasmon resonance of Au nanoparticles plays a crucial role in the enhancement of visible light absorption. Secondly, the potential barrier on the Zn₂SnO₄/SnO₂ surface caused by Au nanoparticles can suppress electron–hole recombination, diminish the loss of electrons during the transfer process and improve the photocurrent density. Thirdly, the enhanced photovoltaic performance can also be attributed to the unique structural characteristics of hollow rounded cubes.