Investigating the influence of copper (I) thiocyanate as a hole transport layer in efficiency of methylammonium lead iodide perovskite solar cells

In the past few years, organic-inorganic perovskite solar cells have been improved drastically in terms of solar to electric power conversion efficiency (PCE) and stability [1]. The hole-transport material (HTM) is an important part of cell which facilitates the separation of electron-hole pairs [2]. In this research, the copper (I) thiocyanate (CuSCN) was synthesized and used as an efficient and cheap hole transport layer in methylammonium lead iodide (MAPbI3) perovskite solar cell. The FTO glass is used as anode. Initially, the thin layer of titanium oxide as a blocking layer is deposited on the FTO substrate using the spin-coating method (2000 rpm, 20 s) and annealed at 450 ℃ for 30 min. Then, a layer of mesoporous titanium oxide prepared from commercial TiO2 (P25, Degussa) was deposited on the previous layer. A thin layer of MAPbI3 was spin coated on the titanium oxide mesoporous layer as active layer. The synthesized CuSCN as a HTM was deposited on perovskite layer by spin-coating method (2000 rpm, 20 s) and dried at 120 ℃ for 15 min. Finally, the graphite powder was used as cathode. The I-V curves were recorded in -1-1 V under dark and illumination of solar light by Solar simulator (AM1.5). The open circuit voltage (VOC) of MAPbI3 solar cell without HTM layer was obtained 670 mV. In the presence of CuSCN, the VOC and other photovoltaic parameters were increased indicating the improvement of lead based perovskite solar cell in the presence of CuSCN as an efficient and cheap hole transport layer.