Designing small push-pull chromophores hole transport materials for perovskite solar cells (PSCs) and organic solar cells with optimum performance

This research project focused on the modeling and analysis of novel hole-transporting materials (HTMs) using Density Functional Theory (DFT) and Time-Dependent (TD-DFT). The study included the VNMR reference compound and newly proposed chromophores (VNM1–VNM5), designed with triarylamine cores and thiophene-linked end-capped acceptors. The investigation aimed to evaluate their optoelectronic, nonlinear optical (NLO), photovoltaic, and optical properties, with the goal of establishing these HTMs as cost-effective candidates for highly efficient perovskite solar cells (PSCs). The results indicate that these HTMs exhibit better planarity, lower Highest Occupied Molecular Orbital (HOMO) energies, and enhanced solubility, alongside a narrower energy band gap (E_gap) ranging from 1.61 to 1.27 eV, compared to the reference VNMR (1.95 eV) in the gas phase. In ethanol solvent, the E_gap for VNMR is 1.85 eV, while it ranges from 1.44 to 1.10 eV for VNM1–VNM5. These properties enable efficient hole extraction and solution processing, improving hole transport from the perovskite layer and leading to higher open-circuit voltages (0.18 V–0.33 V) than the reference molecule (0.17 V). The electron and hole reorganization energies range from 0.105 eV to 0.179 eV and 0.041 eV to 0.054 eV, respectively, suggesting improved hole mobility for PSCs. Additionally, all designed HTMs showed better fill factors (0.62–0.74) compared to the reference molecule (0.61). The findings indicate that the VNM1–VNM5 molecules are promising HTMs for the production of high-performance PSCs, with potential future applications in the organic solar cells industry.