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Systematic study using quantum chemical method the following three systems: (1) benzo [1,2-b :4,5-b '] dithiophene-conjugated polymer; (2) styrene-containing conjugated polythiophene derivatives branched; (3) indolocarbazole - acceptor alternating conjugated copolymer First, using the density functional theory (DFT) B3LYP method, poly 4,8 - double dodecyloxy benzo [1,2-b :4,5-b '] dithiophene (PBDT), polyethylene 4,8 - bis 22 alkoxy-benzo [1,2-b :4,5-b'] dithiophene alternately (2,5) the thiophene (PBDTT) and poly 4,8 - bis 22 alkoxy benzo [1,2-b :4,5-b '] dithiophene are alternately (2,9) thiophene and [3, 4-b] pyrazine (PBDTTPZ) geometry optimization calculations. Optimized based on the use of time-dependent density functional theory (TD-DFT) calculation of the optical properties, has been the lowest excited can (Eg), absorption wavelength and electronic properties. The HOMO and LUMO energy gap equal to the difference in energy between the LUMO and HOMO. The calculated results with the experimental results very well, the calculation results for the regulation of the conjugate bandgap of the polymer and the absorption band provides a useful reference. Second, using the density functional theory (DFT) method and the method of time-dependent density functional theory (TD-DFT) were calculated poly [3 - (styrene) thiophene] (P3PVT) Series: (PEHPVT) n (PT1) n and (PT4) n structure and electronic properties. Polymer HOMO-LUMO energy gap (△ HL), and the minimum excitation energy (Eg) is obtained by extrapolation. The results show that: the conjugated polymer side chain to be able to adjust the absorption peak and the HOMO-LUMO energy gap. Finally, the method of density functional theory (DFT) B3LYP study of three kinds the indolocarbazole - receptor alternating conjugated copolymer: poly [2,8 - (5,11 - two (2 - ethyl hexyl) indole indole [3,2-b] and carbazole) - alternately -5,7 - (2,3 - didodecyl thiophene [3,4-b] pyrazinyl)] (P281C-TP12), poly [ 2,8 - (5,11 - bis (2 - ethyl hexyl) indole [3,2-b] and carbazole) - alternate -5,7 - (2,3 - bis (4 - (2 - B yl-hexyloxy) phenyl) - thiophene [3,4-b] pyrazine) (P281C-TPO), 4,7 - poly [2,8 - (5,11 - di (2 - ethyl hexyl) indole-[3,2-b] carbazole) - alternately - (2,1,3 - benzothiopyrano oxadiazol) (P281C-BT). Neutral and anionic state and the cationic state geometry optimization. In the optimization based on the application of the TD-DFT calculated polymer ΔH-L, the absorption wavelength of the excitation energy and the lowest. Fully optimized using B3LYP/6-31G * polymer cation and anion to calculate ionization potential (IP) and electron affinity can (Ea). In this thesis, theory systematically on a series of conjugated polymer solar cell material structure and photovoltaic performance parameters of the research and analysis. The results show that the combination of density functional theory TDDFT able to study the conjugated polymer solar cell materials, according to the geometrical structure and electronic properties of new polymer solar cell materials can be designed.
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