Designing of pyrrolopyrazine-based electron transporting materials with architecture (A1-D-A2) in perovskite solar cells: a DFT study

In this study, the proposed method involves the confident insertion of π-spacer fragments between donor and acceptor parts of a newly designed (A1-D-A2) molecule into the reference molecule (PP2). Frontier molecular orbitals study using MPW1PW91/6-31G(d,p) level of DFT demonstrates that all designed molecules possess a lower band gap (2.62-3.35 eV) in comparison to R (3.77 eV). The absorption properties clearly show that all the designed molecules (DD1-DD8) have higher absorption values (434.44-566.40 nm) in the gas phase and (498.65-624.01 nm) in the solvent phase compared to R values of 380.32 nm in the gas phase and 415.61 nm in the solvent phase. Significant LHE values and the lowest λ_e values (0.0062-0.0110 eV) are observed in the designed molecules. This study will help researchers to design molecules for the development of efficient PSCs devices.