Facile growth of a Sb2Se3 nanorod array induced by a MoSe2 interlayer and its application in 3D p–n junction solar cells

Abstract

A uniformly grown Sb₂Se₃ nanorod array, with the introduction of a MoSe₂ interlayer, obtained by a co-evaporation process and its application in three-dimensional (3D) p–n junction high-efficiency Sb₂Se₃ solar cells were investigated in this study. The MoSe₂ interlayer played a crucial role as a seed layer for the preferential growth of Sb₂Se₃ crystals, which facilitated the formation of a Sb₂Se₃ nanorod array regardless of the process conditions. 3D p–n junction between the Sb₂Se₃ nanorod array and the CdS buffer layer improved the short-circuit current of Sb₂Se₃ solar cells due to improved carrier transportation from the Sb₂Se₃ absorber to the CdS buffer. The MoSe₂ interlayer also improved the contact quality between the Sb₂Se₃ nanorod array and the Mo substrate by forming a quasi-ohmic contact, which resulted in a higher open-circuit voltage due to a reduced contact barrier and series resistance in Sb₂Se₃ solar cells. The crystal growth rate of Sb₂Se₃ was controlled by the source evaporation rate and substrate temperature to tune the final nanostructure and crystalline orientation of the co-evaporated Sb₂Se₃ nanorods array. 3D p–n junction solar cells based on an ordered and (hk1) preferentially oriented Sb₂Se₃ nanorod array showed a power conversion efficiency of 5.637%. Therefore, by including a MoSe₂ interlayer, it is possible to achieve high-efficiency 3D p–n junction Sb₂Se₃ solar cells.