Trap-Door-Like Irreversible Photoinduced Charge Transfer in a Donor-Acceptor Complex

For efficient conversion of light into useful energy sources, it is very important to study and describe the first steps of primary charge-transfer process in natural structures and artificial devices. The time scale of these processes in artificial photosynthetic and photovoltaic devices is on the order of femto- to picoseconds and involves vibronic coupling of electrons and nuclei and also nuclear alleviation to enhance charge separation. Here we present an atomistic description of the photoexcited electron dynamics in a noncovalently bonded system formed by an hydrogenated nanodiamond as donor and a perylene diimide as an acceptor. The complex shows extremely fast charge transfer, separation, and stabilization within 90 fs. This stabilization is purely electronic in nature. To the best of our knowledge, these results show for the first time that it is possible to stabilize charge without polaron formation or nuclear relaxation, reaching a steady state enhanced by a pure electronic reorganization.