Extent of charge separation and exciton delocalization for electronically excited states in a triphenylamine-C60 donor–acceptor conjugate: a combined molecular dynamics and TD-DFT study

Abstract

Triphenylamine-pyrrolidine-C-60 is a potential material to construct high-efficient dye-sensitized solar cells. A combined molecular dynamics and time-dependent density functional theory study has been carried out to analyze charge separation and exciton delocalization in excited states of two constitutional isomers of this compound. Insight into the intrinsic structure of the excited states is provided. The presence of states with a hybrid excitonic and charge-transfer character is suggested to promote the direct charge separation process by excitation, which could have a significant impact on the efficiency of the light-harvesting species. A greater amount of such hybrid states is found at short distances between the triphenylamine fragment and the C-60 cage