Charge transport and optical properties tuning via DFT/TD-DFT modeling of SAM-driven hole-selective layers for inverted perovskite solar cells
摘要
Conventional hole-selective layers (HSLs), such as Spiro-OMeTAD, remain popular in perovskite solar cells (PSCs) but are associated with several disadvantages, including parasitic light absorption, low moisture resistance, and high fabrication cost. To address these issues, we proposed five novel self-assembled monolayer (SAM)-derived donor-p-acceptor HSLs (SDA1-SDA5) to enhance charge transport and energy localization in inverted PSCs. SDA2 and SDA3 were the best performers among them. SDA2 had the lowest hole reorganization energy (0.00768 eV) and the highest hole transfer rate (6.27×1016 s−1) compared to the reference R7B, making it easier to access the charge. It is demonstrated that they display good HOMO alignment with the perovskite valence band, good light-harvesting capacity with red-shifted absorption to 720 nm, and better solubility and processability suggested by high dipole moments (15.4946D) and negative solvation energies (− 8.89 kcal/mol). The HOMO alignments favor the extraction of holes. The charge separations and the reduced recombination losses were evidenced by a high D-index (6.26 Å), low overlap integrals, and the obvious separation of electrons and holes as seen through the charge density and transition density matrix analyses. This work presents a forward-looking computational approach for developing high-performance HSLs in future PSC technologies.
Graphical Abstract