Study On Intramolecular Charge Transfer About Two Material Cules Of Solar Cells Mole

Energy is the material basis of human social activities. With the rapiddevelopment of the global economy, the demand of energy for human has beengrowing. But petroleum and coal-based mineral resources are becoming depleted.So it has tremendous significance for the promotion of social progress, economicdevelopment, and improve human life to develop the use of non-polluting new energy.Solar energy is a clean, natural energy with its long-term, renewable, non-pollutingand many other advantages.Because of those advantages,solar energy has beenapproved by people of all ages. One of the most effective way to make use of solarenergy is the solar cell technology.The bulk heterojunction (BHJ) solar cell is one kind of polymer solar cells,where an active light-absorbing layer consists of a mixture of a p-type material(generally a semiconducting polymer) and an n-type material (generally fullerenederivatives). When the sunlight shines on the light-absorbing layer, exciton(electron-hole pairs) has been produced. Exciton spread to the contact interface of donor–acceptor and then separated into free electrons and holes. With the drive of built-inelectric field, free electrons travel through the receptor material channel to the anodeand holes travel through the donor material passage to the cathode. Thus photocurrenthas been produced, the photoelectric conversion completed.In this paper, we studied two organic molecules DTS-TPD and DTG-TPD as ourresearch object. We used the quantum chemistry methods in the theoretical study.Researched the property of their excited state, transition energy and oscillator strengthwith parameter of TD-DFT B3LYP6-31G（d）of Time Dependent-Density FunctionalTheory.Analysis and explore the absorption spectra and intramolecular chargetransfer of the two molecules. The absorption spectrum of DTS-TPD has two mainvisible bands at635.76nm and470.09nm which were mainly attributed to theelectronic transition from HOMOâ†'LUMO and HOMO-1â†'LUMO+1.And theabsorption spectrum of DTG-TPD has two main visible bands at633.55nm and 467.86nm which were also mainly attributed to the electronic transition fromHOMOâ†'LUMO and HOMO-1â†'LUMO+1.3D cube representations including charge difference density visualized thecharacter of intramolecular charge transfer of two molecules. Furthermore, we use2Dcube representations to analysis the coherence of electron-hole. Finally, we examineDTS-TPD molecules with the increase in the value of n.