Structural effect on the thermodynamic and electrochemical properties of pyrene-based hole transport materials

Abstract

We introduce six di-methoxyphenylamine-substituted pyrene arylamine derivatives as new hole transport materials (HTMs) by changing the position of OMe substituent on the phenylamine group and compare with three other derivatives denoted as N,N-di-p-methoxyphenyl-amine-substituted pyrene arylamine (para-PyA, -PyB, and -PyC) as references. The electronic, absorption and emission spectra, and transport properties of the new materials are investigated via density functional theory (DFT) calculations in combination with the Marcus hopping model. The stability and solubility of all the derivatives along with the parameters affecting the open circuit voltage (Voc), fill factor (FF), and short-circuit current density (Jsc) of the corresponding solar cells are obtained and discussed. We also examine the oxidation forms (+1 and +2) of structures to find the reasons for instability and reduction in efficiency of the device after the formation of the oxidized forms of HTMs. The results show that among the nine structures studied, the ortho-PyB derivative with CH3NH3PbI3 absorber and ortho-PyA derivative with (FAPbI3)0.85(CH3NH3PbBr3)0.15 absorber are promising HTMs for perovskite solar cells (PSCs) because they have larger Stokes shifts, appropriate highest occupied molecular orbital (HOMO) level, more stability, and acceptable hole mobility.