聚合物中光致载流子的有效途径-激子解离

Charge carrier generation through re-excitations of an exciton in poly(p-phenylene vinylene) molecules

基于紧束缚SSH模型,本文讨论了激子的两种光跃迁,进一步提出了聚合物分子中光致载流子的有效途径-激子解离.我们发现:激子的高能跃迁使激子直接解离为自由的荷电载流子,从而参与聚合物分子中的光电流;低能跃迁形成的激子激发态的解离是强电场相关的,只有在强场下低能跃迁使激子解离为自由的荷电载流子.

Charge carrier generation due to re-excitations of an exciton in poly（p-phenylene vinylene） （PPV） molecules is studied theoretically in the framework of the tight binding approach. Two different kinds of optical transitions for an exciton are suggested. It is found that the high-energy transition will dissociate the exciton into free charges, which is responsible for the photoeurrent. The state from the low-energy transition is strongly field dependent. Only at a strong electric field, does the exciton be dissociated into free charges.