Facile growth of a Sb₂Se₃nanorod array induced by a MoSe₂interlayer and its application in 3D p-n junction solar cells

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.