基于3,4-二烷氧基噻吩的D-A-D型有机共轭分子的合成及其光学和电化学性能

基于Wittig反应合成了新型D-A-D型有机半导体材料——双(2-乙烯基-3,4-二烷氧基噻吩)-对-2,5-二苯基-1,3,4-噁二唑(3,4DAOTV)2-OXD],用核磁共振氢谱(1HNMR)、傅里叶变换红外(FTIR)光谱、高效液相色谱(HPLC)和元素分析法(EA)对化合物的结构进行分析和表征.用紫外-可见(UV-Vis)光谱、荧光(PL)光谱及电化学分析研究其光学和电化学性能.在氯仿溶液中,各化合物的紫外最大吸收波长(λmabasx)在382-383nm之间,光学带能隙在2.92-2.97eV之间,荧光最大发射波长在448-452nm之间,发出明亮的青色光,荧光量子产率可达36.8%-37.6%;在固体薄膜状态下,各化合物于513-516nm处发射出亮蓝绿色光.循环伏安法研究显示:三种大π共轭分子在正、负向区域均表现出明显的氧化、还原现象.其中,5.65-5.70eV的电离势(Ip),与噻吩类有机半导体材料的空穴传输特征相符;电子亲和势(Ia)在2.74-2.88eV之间,与有机电子传输材料的特性相近,这利于电子从阴极的注入和传输.理论计算结果表明,该D-A-D型共轭分子共平面性好和电荷离域程度高,对光电功能材料的分子界面组装、载流子的有效传输和器件量子效率的提高十分有利.

Synthesis, Optical and Electrochemical Properties of Novel 3,4-Dialkyloxythiophene-Based D-A-D Organic Conjugated Molecules

Novel 3,4-dialkyloxythiophene-based D-A-D organic conjugated molecules di(2-vinyl-3,4- dialkyloxythiophene)-p-2,5-bisphenyl-1,3,4-oxadiazole (3,4DAOTV)₂-OXD] were obtained using the Wittig reaction. The structure was effectively characterized using hydrogen nuclear magnetic resonance (¹H NMR), Fourier transform infrared (FTIR) spectroscopy, high pressure liquid chromatography (HPLC) and elemental analysis (EA). The optical and electrochemical properties were studied by UV-Vis, fluorescence spectroscopy, and cyclic voltammetry. The UV-Vis maximum absorption of the three studied compounds ranged between 382-383 nm and their optical bandgaps ranged from 2.92 to 2.97 eV. Their emission maxima ranged from 448 to 452 nm with a bright cyan light and their luminescence quantum yields ranged from 36.8%-37.6% in CHCl₃. As solid films, these compounds emit glaucous light at 513-516 nm. The (3, 4DAOTV)₂-OXDs show oxidation and reduction processes in their cyclic voltammograms. Their ionization potentials of 5.65-5.70 eV coincide with the hole transport ability of thiophenes and their electron affinity values of 2.74-2.88 eV are close to the required properties of an electron transport material. These properties will facilitate electron injection and transfer from the cathode. Theoretical calculations indicate that the D-A-D organic conjugation molecule has high coplanarity and that electrons are delocalized along its backbone, which might result in interfacial molecular self-assembly and efficient charge carrier transport as well as efficient quantum yields of devices.