超快非均质电子转移的优化控制研究(Ⅰ)

Laser pulse control of ultrafast heterogeneous electron transfer

本文用三能级的单振动模型,模拟了从二萘嵌苯到TiO2超快电子转移的动力学过程,发现在弱电子转移耦合下,电子在激光场的作用下激发至分子激发态转移然后到半导体导带,在强电子转移耦合下,电子直接由基态转移到半导体导带。在优化控制的理论模拟中以电子激发态的振动基态为目标态,考虑了不同注入位置条件下的电子转移的动力学过程,研究了优化激光场在给定时间内实现目标态的过程,由于从分子激发态到半导体的超快电子转移,只有当分子激发态能级与半导体导带底能级简并时,才能实现较高的目标态产生率。

With minimal model including the electronic ground state, the excited state of dye and ionized state formed after charge injection, the ultrafast heterogeneous electron transfer from perelyene to TiO2 is studied. It is found that with the weak electron transfer coupling, there is a clear separation of the excited state population and the electron injection into the conduction band. The strong electron transfer coupling results in a direct charge injection by the exciting pulse without intermediate excited state population. Taking the vibrational ground state in the electronic excited state as the target state, the ultrafast heterogeneous electron transfer process in different injection position are studied using the optimal control theory. It is found that the high yield of target state can be realized only if the energy of electronic excited state of dye is degenerated with the bottom of conduction band.