Tuning optical and electronic properties of indanthrene derivatives with electron-withdrawing groups (–Cl, –NO₂ and –C≡N) for enhanced organic solar cell performance: a DFT approach

Abstract In this study, we focused on improving the electronic and optical properties of the reference compound indanthrene (R) by introducing electron-withdrawing groups (−Cl, −C≡N, −NO 2 ). Density functional theory and time-dependent density functional theory calculations were performed using Gaussian 16 software to study indanthrene derivatives as electron acceptor materials. The electronic and optical properties of the designed molecules (M1-M8) were investigated through frontier molecular orbital analysis, UV-visible absorption spectra, density of states, and transition density matrix analysis, utilizing GaussView 6.0 and Multiwfn 3.8 software. The designed molecules exhibit absorption across the entire visible spectrum, with maxima extending up to ∼737 nm. Their electron affinity values range from 3.0 to 4.0 eV, surpassing the fullerene-based acceptor material. Among the designed molecules, M5 stands out with superior photovoltaic parameters, including a narrow optical band gap (∼1.68 eV), exciton binding energy (0.25 eV), higher electron affinity (3.35 eV), an extended excited state lifetime (17.0 ns) owing to its low electron and hole reorganization energies ( λ e ∼ 0.190 eV, and λ h ∼ 0.134 eV), and improved short-circuit current density of ∼15.7 mA cm −2 . The photovoltaic parameters and power conversion efficiency were assessed using the Scharber and Alharbi models. The calculated device parameters, including light harvesting energy and photovoltaic characteristics (V oc , FF, J sc , and PCE), suggest that these molecules, with electron-withdrawing groups, show great potential for use as acceptors in organic solar cells, particularly in terms of stability and power conversion efficiency. Notably, M2 and M5 , with their PCE values exceeding 16%, emerge as outstanding candidates for device performance, impressively outperforming the other designed molecules.