Theoretical Study on Fluorescence Quantum Yield of Thiophene Derivatives

• 1、 School of Marterial and Energy, Southwest University, Chongqing, 400715

Abstract：In the field of organic small molecule fluorescent materials, although oligothiophenes have low fluorescence quantum yield, due to their strong stability and convenient modification, high-performance organic small molecule fluorescent materials derived from oligothiophenes can be obtained through appropriate modification methods. There are many modification methods for oligothiophenes, which can be roughly divided into three categories: introducing end groups, introducing functional groups, and changing polymer lengths. However, the effects of ring fusion and heteroatom substitution on the optical and electronic properties of oligothiophenes are still unclear. In this study, based on pentathiophene, eight molecules (TTTTT, T-TTT-T, TT-T-TT, OOOOO, SOOOS, SOSOS, OSOSO, SSOSS) were systematically designed according to the two types of modification methods, Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TDDFT) were used to systematically calculate the optical and electronic properties of these molecules. Based on this, this paper discusses the mechanism of how different modification methods affect the fluorescence quantum yield of oligothiophenes in detail, then recommend the best modification method for different property requirements, providing reliable modification ideas for the subsequent researchers.

Keywords： Material Physics and Chemistry Oligothiophene DFT/TDDFT Fusion ring Furan substitution Fluorescence quantum yield