Theoretical Investigation into Electronic Structures and Charge Transfer Properties of π-Conjugated System with Different Combinations of Thiophene and Vinyl/Butadiene

• Published in: Chinese journal of chemistry Vol. 30; no. 10; pp. 2501 - 2508
• Main Author: 赵春梅 李春荣 马妍 赵蔡斌 王文亮
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.10.2012; WILEY‐VCH Verlag
• Subjects: butadiene; charge transfer; electronic structure; LUMO能级; TDDFT; thiophene; vinyl; 丁二烯; 乙烯基; 传输性质; 共轭体系; 噻吩; 电子结构; 电荷转移
• ISSN: 1001-604X; 1614-7065
• DOI: 10.1002/cjoc.201200444

A series of combinations of thiophene and vinyl/butadiene were investigated by ab initio and DFT methods to explore their electronic structures and charge transfer properties. The results show that increasing thiophene ring and vinyl number is a rational strategy to raise the HOMO energy levels and lower the LUMO energy levels. Mov- ing the vinyl from the periphery to the core has the slight effect on the HOMO and LUMO energy levels. Further- more, replacing the middle vinyl and end-capped vinyl of 3b （T5V4） with the butadiene can lower LUMO energy levels and then facilitate the electron injection. Above all, the close hole and electron reorganization energies （2h and λ-e） are observed from these compounds. However, the λes are smaller than their respective λhs in some com- pounds, which is relatively rare in organic materials. Especially, the promising ambipolar material 3c （T5B4） is recommended theoretically for possessing the equivalent minimum Ah （0.24 eV） and 2e （0.24 eV）. The absorption wavelengths exhibit red shifts with the increasing of the thiophene ring and the vinyl number under the same con- figuration, which correspond to the reverse order of AEH_L and Eg. The linear relationships are found between experimental lowest singlet excited energies （Eexp） with theoretical values AEH-L and Eg.