A Symmetry‐Broken Charge‐Separated State in the Marcus Inverted Region
Ebin Sebastian, Mahesh Hariharan
Abstract
Abstract We report a long‐lived charge‐separated state in a chromophoric pair ( DC‐PDI 2 ) that uniquely integrates the advantages of fundamental processes of photosynthetic reaction centers: i) Symmetry‐breaking charge‐separation (SB‐CS) and ii) Marcus‐inverted‐region dependence. The near‐orthogonal bichromophoric DC‐PDI 2 manifests an ultrafast evolution of the SB‐CS state with a time constant of =0.35±0.02 ps and a slow charge recombination (CR) kinetics with =4.09±0.01 ns in ACN. The rate constant of CR of DC‐PDI 2 is 11 686 times slower than SB‐CS in ACN, as the CR of the PDI radical ion‐pair occurs in the deep inverted region of the Marcus parabola ( >λ). In contrast, an analogous benzyloxy (BnO)‐substituted DC‐BPDI 2 showcases a ≈10‐fold accelerated CR kinetics with lowering to ≈1536 in ACN, by virtue of a decreased CR driving force. The present investigation demonstrates a control of molecular engineering to tune the energetics and kinetics of the SB‐CS material, which is essential for next‐generation optoelectronic devices.