Unveiling next-generation organic photovoltaics: Quantum mechanical insights into non-fullerene donor-acceptor compounds.

Abstract

Organic photovoltaics (OPVs) have improved greatly in recent years in pursuit for efficient and sustainable energy conversion methods. Specifically, utilizing quantum chemistry approaches such as density functional theory (DFT), the electronic structures, energy levels, and charge transport characteristics of donor-π-acceptor (D-π-A) systems based on non-fullerene donor and acceptor molecules have been examined and synthesized. Non-fullerene acceptors offer several advantages over traditional fullerene-based materials, such as enhanced light absorption, modifiable energy levels, and reduced recombination losses. Quantum mechanical simulations are helpful in the design and development of these materials because they can accurately predict the energy level alignment, molecule interactions, and charge transport properties needed for the high-efficiency of OPVs. The research begins through the selection of electron-donating and electron-accepting non-fullerene polymeric molecules using the unique properties of non-fullerene derivatives and non-fullerene acceptors. The theory uses the B3LYP-D3 method with a 6-31+G (d,p) basis set. PY-IT is used as the reference molecule, and eight molecules PY-IT01-PY-IT08, has been created by changing the end caps of the acceptor units. The created compound has superior photovoltaic characteristics. Focus has been specifically given to the frontier molecular orbitals (FMOs), natural bond order (NBO) analysis, reorganization energies (RE), and absorption spectra in order to assess the viability of charge separation and efficient light absorption. Finally, the molecular electrostatic potential (MEP) analysis, transition density matrix (TDM) analysis, and improved open circuit voltage (Voc) all have been computed. The results of the findings provide new insight to design organic solar cells (OSCs) with improved photovoltaic and solar energy conversion capabilities, which has great potential for the future development of more dependable and efficient OSCs.