Theoretical Study On Intramolecular Charge Transfer About Two Type Of Organic Photo-electronic Material

Entering the 21 st century,contribution of the rapid development of science and technology gives mankind far beyond human expectations.However,human had to face to the problems hidden behind the side effects.The problems of deterioration of the environment and the energy crisis not only hinder the pace of progress of mankind,more importantly,they threat to human survival,and therefore we need a new type of energy toease the pressure of survival.Organic semiconductor materials,as an important representative of new energy materials,play an important role with their widely sources and molecular structure in the electronics industry.Although there is a lack of performance and efficiency,but it allowedto study the work of the organic semiconductor material more meaningful.Theoretical studies of organic semiconductor materials,to improve efficiency and enhance the properties of the material has important significance.The optoelectronic properties of organic semiconductor material are directly affected by the intramolecular excited charge-transfer states.Therefore the study in the microcosmic fields of molecular light induced charge transfer,compound structure and the situation of electronic transition and intramolecular interaction,which offers deep-seated theoretical principle for the study of the new material.This paper explores several kinds of molecular structures of organic semiconductor materials and the characteristicsof ground state and the excited state by Density Functional Theory of quantum chemistry methods.(1)The ground and excited states properties of the two hexazapentacene derivatives,TTHAP and OHHAO,were investigated theoretically with the quantum chemistry methods and they were investigated by using DFT with B3 LYP functional and 6-31G(d)basis set.There were two peaks of the absorption spectrum of TTHAP,556.68 nm and 381.14 nm,respectively,from the contribution by HOMO-1→LUMO and HOMO→LUMO+2.And then we used TD-DFT to calculate the Charge Density Difference and Transition Density.Finally,We discussed absorption with transition densities,charge transfer and provided information about the electron-hole coherence and delocalization by 2D site real space analysis and 3D cube real space analysis.(2)Similarly,we made analysis of the groundproperties,absorption spectra andexcited state properties of two derivatives of diphenylethene in the same way.And 3D cube including transition densities and charge transfer visualized the character of intramolecular charge transfer of the two molecular.Furthermore 2D cube representations were used to visualize the coherence of electron-hole.