9.2%-efficient core-shell structured antimony selenide nanorod array solar cells

Antimony selenide (Sb₂Se₃) has a one-dimensional (1D) crystal structure comprising of covalently bonded (Sb₄Se₆)n ribbons stacking together through van der Waals force. This special structure results in anisotropic optical and electrical properties. Currently, the photovoltaic device performance is dominated by the grain orientation in the Sb₂Se₃ thin film absorbers. Effective approaches to enhance the carrier collection and overall power-conversion efficiency are urgently required. Here, we report the construction of Sb₂Se₃ solar cells with high-quality Sb₂Se₃ nanorod arrays absorber along the [001] direction, which is beneficial for sun-light absorption and charge carrier extraction. An efficiency of 9.2%, which is the highest value reported so far for this type of solar cells, is achieved by junction interface engineering. Our cell design provides an approach to further improve the efficiency of Sb₂Se₃-based solar cells.