The Effect Of Vibrational Coherence Among The Excited Vibrational Levels On Electron Transfer Rate

With the aggravation of energy shortage and deterioration of environment, scientists are paying more and more attention to the utilization of solar energy. The dye-sensitizing semiconductor as a novel kind of energy material with the advantages of low price and exceptional performance stands out from the others. Therefore, study on dye-sensitizing semiconductor materials will further promote the practical application of solar energy. Through methods such as controlling the size of quantum dots and changing the bonds between the dye and the semiconductor and so on, we can assume a group of dyes and semiconductors matching each other, based on which it is reasonable to investigate the factors influencing the electronic transfer rate on the interface between the dye and the semiconductor from theoretical point.On foundation of the theory of pump-probe technology, this article studied electronic transfer mechanism on the interface between the dye and the semiconductor. Based on Schrodinger Equation,the electronic vibration wave functions of the dye/semiconductor system, and the Hamiltonian we got the probability amplitude changing with the time. The probability amplitude determines the probability that the electron takes place on the vibrational levels of excite state. Finally we got the time-dependent occupation of the excited molecule, which is agreement with the already existed theories formula. Moreover, this article firstly gives a empirical formula which is on the basis of the formula derivation and theory knowledge, This empirical formula is about the Franck-Condon factor of the wave functions, which lays a solid foundation for the further theory study on the electronic transfer between the dye and the semiconductor.First from the time-dependent occupation of the excited molecule and the empirical formula, this article got the curve which displays the time-dependent occupation of the excited molecule on the different conditions. Then by comparing with the existed theories of the curve, we observed that they have the same trend, which can reflect the rationality of the experience formula. Second, based on the curve and the experience formula, we made an amendment to the experience formula, further defined the parameters of the experience formula. Finally, on the basis of the verification of the experience formula, we simuated the situation of the electronic transfer taking place on the interface of perylene-TiO2, and the simulative results match with the experimental results very well. And eventually it is reasonable that the Franck-Condon factor is subject to a Posson distribution, which is the electronic vibrational overlap factor between the dye and the semiconductor's wave functions of electronic vibration.