Designing some effective hole transport materials for perovskite solar cells

Several isoindigo-based HTMs were designed and investigated using density functional theory (DFT) computations. It was found that the energies of HOMO and LUMO levels were increased with an enhancement in the electron-donating character of substituents located on the diphenylamine moieties. The molecules with NH۲, NHMe, and N(Me)۲ substituents exhibited appropriate energy level alignments with respect to MAPbI۳, which indicated the hole could be injected from the MAPbI۳ to the designedHTMs. All of HTMs illustrated considerably greater hole mobility than that of the Spiro-OMeTAD confirming they have the potential for replacing the Spiro-OMeTAD in PSCs.