Structure–Property Relationships from Atomistic Multiscale Simulations of the Relevant Processes in Organic Solar Cells. I. Thermodynamic Aspects

Interface structures of a variety of molecular p-type semiconductors in heterojunction with fullerene C<sub>60</sub> were generated in molecular dynamic simulations. Using the dimer method (i.e., dimers were used as the quantum-mechanical system) along with a continuum solvation approach and macroscopic electric fields, energetic profiles of the interfaces of organic solar cells (OSCs) were calculated. Several important loss mechanisms, such as exciton trapping, charge trapping, and interfacial charge-transfer traps, were observed. Structure–property relationships were established. They reveal that apart from the molecular orientation and dipolarity, molecular size is an important parameter that influences potential loss mechanisms.