Four new copolymers P1–P4 containing the same backbone of bithiazole acceptor unit and benzodithiophene donor unit but different side chain pattern were synthesized by Pd-catalyzed Stille coupling. The effect of the side chains on backbone conformation, solubility, absorption spectra, energy levels, charge transport, blend film morphology, and photovoltaicproperties of the polymers were experimentally
通过Pd催化的Stille偶联合成了四种新的共聚物P1 – P4,它们具有相同的噻唑受体单元主链和苯并二噻吩供体单元主链,但侧链模式不同。侧链对主链构象,溶解度,吸收光谱,能级,电荷传输,混合膜形态和聚合物的光伏性能的影响进行了实验和理论上的研究。主链的平面增大的顺序P3 < P4 < P1 ≈ P2。随着主链平面度的增加,聚合物在膜中的最大吸收峰出现红移,从448 nm移至544 nm,HOMO从-6.0向上移至-6.0 eV,LUMO从-2.6向下移至-2.9 eV,并增加空穴迁移率从4.7×10 –4到0.06 cm 2 V –1 s –1。当增加聚合物主链的平面度时,聚合物:PC 71 BM共混物中的相分离尺寸增加。基于P4:PC 71 BM(1:1,w / w)的聚合物太阳能电池在AM 1.5、100 mW cm –2下显示出2.54%的最高功率转换效率归因于宽吸收,高迁移率和合