Copper (I) selenocyanate (CuSeCN): Eco-friendly solution-processable deposition of hole transport layer for organic solar cells

•Solution-processable deposition of CuSeCN as an efficient hole transport layer for solar cells.•Eco-friendly and inexpensive DMSO and DMF solvents were used as an alternative to foul-smelling diethyl sulfide solvent.•The optical, electrical, and morphological properties of the HTLs were studied.•Photovoltaic devices were fabricated with a simple device geometry ITO/CuSeCN/PCDTBT:PC71BM/Al. Recently, a lot of research on solution-processable deposition of copper (I) thiocyanate (CuSCN) as an efficient hole transport layer (HTL) for solar cells has been reported. Herein, we report the higher chalcogen analogue copper (I) selenocyanate (CuSeCN), as efficient HTL for organic solar cells. Eco-friendly and inexpensive DMSO and DMF solvents were used for solution-processable deposition of CuSeCN thin films. The optical, electrical, and morphological properties of the HTL were studied using UV–vis-NIR spectroscopy, cyclic voltammetry, and scanning electron microscopy. Density functional theory calculations were performed to understand the HOMO level and band gap of the HTL. Two different concentrations of CuSeCN solution (DMSO and DMF) were used for HTL deposition for fabrication of photovoltaic devices. Photovoltaic devices were fabricated with a simple device geometry ITO/CuSeCN/PCDTBT:PC71BM/Al and maximum power conversion efficiencies were achieved up to 3.92% and 4.03% using DMSO and DMF as deposition solvents, respectively under ambient conditions, which are comparable to devices made by PEDOT:PSS and MoOx as HTLs under identical conditions.