Towards Development of High-performance Perovskite Solar cells based on Pyrrole Materials for Hole Transport Layer by using Computational Approach

Perovskite solar cells (PSCs) have emerged as innovative materials in advanced photovoltaic technology due to their enhanced efficiency and good stability. While considering role of dopant materials in HTMs especially Spiro-OMeTAD through previous studies, a bi-functional dopant named PFPPY has been brought into special attention. Based on framework of experimentally synthesized PFPPY, five dopant molecules (P1–P5) have been designed through structural alterations at peripheral sites. These newly developed molecules, sharing a common core i.e. 1,4-dihydropyrrolo[3,2-b]pyrrole (PPY), were then theoretically studied and related to reference via computational approach. Distribution of frontier molecular orbitals (FMOs) along with density of states, spectral properties, reorganizational energies, binding energy, and transition density matrix analysis was practiced at
ω
B97XD functional using DFT and TD–DFT methodology. Bathochromic shift of absorption (in dichloromethane) was clearly observed for all designed dopants (P1–P5) than reference PFPPY which sets the ways for reduced optical band gaps (
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. The energy gaps (
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of these five novel designed materials were found to be lesser comparaed to PFPPY which leads to excellent ICT properties. Of all dopant molecules, highest dipole moment (6.511401 D) possessed by P4 is credited to its maximum absorption peak (1008 nm) in infrared region. However, greater hole transfer rate was disclosed by P1 relative to other designed dopants because of its lowest reorganization energy values. According to above computed results, we expect that molecular engineering of pyrrole-based dopant molecules (P1–P5) will allow them to act as promising HTMs. Conclusively, these molecules have potential to substitute PFPPY and are highly recommend in photovoltaic field for future work.