Review on the DFT computation of bulk heterojunction and dye-sensitized organic solar cell properties

Organic solar cells (OSCs) represent a promising renewable energy technology due to their flexibility, low production cost, and environmental sustainability. To advance OSC efficiency and stability, density functional theory (DFT) has emerged as a powerful computational tool, enabling the prediction and optimization of critical properties at the molecular and device levels. This review highlights the key properties of bulk heterojunction solar (BHJ) solar cells and dye-sensitized solar cells (DSSCs) that can be accurately computed using DFT, including electronic structure properties (HOMO-LUMO energy levels, bandgap energies, and exciton binding energies, which influence charge separation and transport); optical properties (absorption spectra and light-harvesting efficiency, essential for maximizing photon capture); charge transport properties (reorganization energies, electron, and hole mobilities, and charge transfer rates that govern carrier dynamics within devices); interfacial properties (energy alignment at donor-acceptor interfaces, contributing to efficient charge separation and minimizing recombination); and chemical reactivity descriptors (ionization potential, electron affinity, chemical hardness, and electrophilicity, which facilitate material screening for OSC applications). We also show how to compute OSCs' power conversion efficiency (PCE) from DFT.

The review also discusses the importance of selecting appropriate exchange-correlation functionals and basis sets to ensure the accuracy of DFT predictions. By providing reliable computational insights, DFT accelerates the rational design of OSC materials, guides experimental efforts, and reduces resource demands. This work underscores DFT's pivotal role in optimizing OSC performance and fostering the development of next-generation photovoltaic technologies.