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.

An antimony sulfide (Sb₂S₃) semiconductor is appealing as a promising light absorber due to its suitable bandgap (1.5–1.7 eV), ‘one dimensional’ crystal structure and non-toxic constituents.

In this work, we present an alternative route to supply excessive selenium (Se) for the deposition of Sb₂Se₃ thin films by the co-evaporation of Se and Sb₂Se₃. Scanning electron microscopy (SEM) images showed that additional Se modified the growth process and surface morphology of Sb₂Se₃ thin films. X-ray diffraction (XRD) patterns confirmed that this co-evaporation process enhanced the beneficiary preferred orientations, and capacitance–voltage (C–V) measurement showed that the carrier concentration of the Sb₂Se₃ absorber increased with the additional evaporation of Se. Accordingly, the efficiency of the devices employing co-evaporated Sb₂Se₃ absorber layers increased significantly from 2.1 to 3.47% with a open-circuit voltage (V _OC) of 364 mV, a short-circuit current density (J _SC) of 23.14 mA/cm², and a fill factor (FF) of 41.26%.

A novel interface engineering strategy with a photo-annealing treatment is proposed for regulating the interface of the Sb ₂ Se ₃ /CdS heterojunction.