Excitons The Nature of Excited States in Conjugated Polymers

1 Excitons The Nature of Excited States in Conjugated Polymers 

Transitions between symmetry-allowed electronic states give rise to optical absorption. Simplistically, the absorption of a photon promotes an electron from the HOMO to the LUMO of the polymer, creating a singlet excited state with the energy 

It can be significant vhen the electron and hole are separated and the exchange energy is low, but in the case of a confined exciton state it will be negligible. 

For a more detailed overview, the interested reader is referred to a recent review on triplet states in organic semiconductors by Kohler and Bassler [17]. 

---