Exploring novel naphthalene-fused octacyclic core-based non-fullerene acceptor materials with augmented optoelectronic attributes for stable and efficient solar cells

Abstract

To meet the growing need for high-efficiency photovoltaic materials in today's high-tech applications, ten acceptor molecules (SH01-SH10) with naphthalene-fused octacyclic electron-donating central core NITT are proposed. End-capped structural-alterations on reference R (NITT-2F) with strong electron-drawing groups (A01-A10) are performed for attaining improved optoelectronic characteristics and possible applications in organic solar cells (OSCs). In comparison to the reference R (NITT-2F), key parameters such as FMO analysis, energy gap (Egap), open-circuit voltage (VOC), absorption spectra (λmax), excitation energy (Ex), transition density matrix (TDM) with binding energy (Eb), the density of states (DOS), reorganization energy of the electron (λe) and hole (λh), and charge transfer with PM6 donor substance are perceived. It is found that all proposed molecules (SH01-SH10) have a reduced energy gap (2.104–1.901 eV), a broader absorption spectrum (707–820 nm), and smaller excitation energy (1.75–1.51 eV) as compared to reference molecule NITT-2F values 2.132 eV, 675 nm and 1.79 eV respectively. The significant charge transfers and 0.23 eV decrease in the Egap is noted for the designed molecule SH05. Results confirmed that all proposed molecules, especially SH05 could be an excellent choice for OSCs candidate due to the combination of strong electron-withdrawing effect in end-capped acceptor unit and extended conjugation, as well as its promising photovoltaic properties, which include the lowest Egap (1.901 eV), highest λmax (820 nm (in chloroform) and 729 nm (in gas phase)) with Ex values of 1.51 and 1.70 eV respectively, slightest electron mobility (λe = 0.0090 eV) and hole mobility (λh = 0.0073 eV), highest ionization potential (6.826 eV) and electron affinity (3.384 eV), and fine value of VOC=1.02 V with respect to (ǀEPM6HOMOǀ - ǀESH05LUMOǀ). End-capped acceptor alterations are an acceptable way to attain the desired optoelectronic characteristics demonstrated in this research work. This study can be essential in achieving efficient novel non-fullerene OSCs with higher performance, low cost, and higher optical absorption coefficient. Thus, proposed molecules (SH01-SH10) with proficient electron and hole transfer mobilities and optoelectronic features are recommended to develop higher-efficiency solar cells.