of extra thiophene units (TQT2) induces a decrease in the optical gap. The comparison with the polymer PTQT further elucidates on the role of delocalization extension to the observed shift of the lower energy transitions to the near infrared (NIR) spectral range. All the materials were used as electron-donors in solution-processed bulk heterojunction solar cells (BHJ-OSCs) with PCBM as acceptor and TQT1
两个新分子TQT1和TQT2,以及一个聚合物
PTQT,其核心基于[1,2,5]
噻二唑并[3,4- g ]
喹喔啉(TQ),低聚醚取代的苯基作为受体和
噻吩(T )或
联苯噻吩(T2)作为供体进行合成,表征和用于光伏器件中。为了比较,还合成了类似的聚合物PQT,其中
喹喔啉单元(Q)代替了TQ。光学带隙按以下顺序减小:PQT(1.83 eV),TQT1(1.68 eV),TQT2(1.31 eV),
PTQT(0.78eV),这是针对共轭聚合物获得的最小光学带隙之一。密度泛函理论计算和溶剂变色研究表明,在TQT1中,
噻吩环带来的共轭扩展主要影响HOMO轨道,而LUMO则位于TQ单元中。因此,HOMO-LUMO激发具有从
噻吩端到TQ核的分子内电荷转移(ICT)特性,并且额外的
噻吩单元(TQT2)的加入会引起光学间隙的减小。与聚合物
PTQT的比较进一步阐明了离域扩展对观察到的较低能跃迁向近红外(NIR)光