Fluorinated copper phthalocyanine as an electron transport material in perovskite solar cell

Abstract

The state-of-art charge transport materials, TiO2 and Spiro-OMeTAD suffer from various drawbacks such as instability, lengthy fabrication procedure and low charge mobilities. In this paper, we have studied copper phthalocyanine (CuPc) and halogen-substituted copper phthalocyanine (X16CuPc; X = F, Cl, Br, I) through density functional theory (DFT) and determined their ground state properties, excited state properties and solubility in DMSO (widely used solvent in the fabrication of perovskite solar cell [PSC]). We have shown that fluorinated copper phthalocyanine(F16CuPc) acts as an electron transport layer (ETL) and CuPc acts as a hole transport layer (HTL) in MAPbI3-based PSC. The moisture stability of CuPc and F16CuPc has been established and it has been shown that CuPc and F16CuPc will protect the perovskite layer from degradation due to the presence of moisture in the surroundings. Using the properties obtained via DFT, PSC has been simulated using SCAPS, and it is established that CuPc as hole transport material and F16CuPc as electron transport material gives better efficiency compared with the state of art charge transport materials (TiO2 and Spiro-OMeTAD). The device has been optimized with respect to (w.r.t.) thickness, doping concentration, defect density and interface defect density. We have studied the effect of series resistance, shunt resistance and temperature on the performance of PSC and this configuration has shown good thermal stability. Carbon has been proposed as an alternative to gold as the back contact thereby making our device more economical. The optimized device showed quantum efficiency of (81.59% to 98.69%) in the visible region. A fill factor of 79.01%, power conversion efficiency of 22.30% has been obtained.