给、吸电子取代基对2,1,3-苯并噻二唑衍生物电子、光谱、电荷传输性质以及稳定性影响的理论研究

Theoretical Study on the Electronic,Optical,Charge Transport Properties,and Stability of Electron-Donating/-withdrawing Groups Substituted BTD-based Derivatives

本文采用量子化学方法研究了给、吸电子取代基[-CH3,-NH2,-CN,-NO2]对2,1,3-苯并噻二唑衍生物的电子性质、光谱性质、电荷传输性质以及稳定性的影响.研究结果表明,与母体分子相比,-CH3、-NH2取代升高了最高占据轨道和最低空轨道的能量,-CN、-NO2取代降低了最高占据轨道和最低空轨道的能量.由于最高占据轨道和最低空轨道的能量升高或降低的程度相当,与母体分子相比,能隙变化都很小.因为能隙变化很小,给、吸电子取代基取代没有使母体分子的吸收和发射光谱发生明显的变化.与母体分子相比,-CN、-NO2取代有利于空穴和电子传输性能的提高.所有取代衍生物具有较小的空穴重组能,可以作为有机发光二极管的空穴传输材料.-CN、-NO2取代衍生物的稳定性高于母体分子.

In this study our aim is to explore the variation in the electronic, optical, charge transport properties and stability upon the electmn-donating/-withdrawing substitutions [ - CH3, - NH2, - CN, - NO2 ] based on the 2, 1,3- benzothiadiazole derivative by quantum-chemical calculations. Our resuhs show that, in comparison with those of the pristine molecule, - CH3 and - NH2 substitutions increase both the energies of the highest occupied molecular orbital and thelowest unoccupied orbital, while - CN and - NO2 substitutions decrease both the energies of the highest occupied molecular orbital and the lowest unoccupied orbital. The energy gaps are almost the same as the pristine molecule. Compared to those of the pristine molecule, the absorption and emission spectra of electron-donating and -withdrawing substituted derivatives exhibit small shifts. The hole reorganization energies of electron-donating and -withdrawing substituted derivatives are small to be used as hole transportation materials in organic light-emitting diodes （OLEDs）. Finally, the stabilities of - CN and - NO2 substituted derivatives are higher than that of the pristine molecule.