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本文分别以三苯胺、N-苯基咔唑和吲哚[3,2,1-jk]咔唑为给体,选择3,6-和2,7-位连接的咔唑为π-桥与氰基乙酸受体键连合成了两个系列共6个D-π-A型染料分子,研究了以它们为光敏剂的染料敏化太阳能电池器件的光伏性能.通过对比发现,给体单元相同的染料分子,以2,7-位连接的咔唑为π-桥时其共轭骨架的π-电子离域比3,6-位连接更好,因而其分子内电荷转移吸收明显变宽并增强,表现出更好的分子捕光能力,相应电池器件的短路电流密度(J_(sc))更大,展示了更高的光电转换效率;当π-桥相同时,给体单元由三苯胺依次变换为N-苯基咔唑和吲哚[3,2,1-jk]咔唑后,伴随苯环之间的直接键连其分子共平面性增强,氮原子上孤对电子参与共轭的程度增大,这虽有利于给体单元共轭骨架的π-电子离域,但会导致氮原子孤对电子参与的分子内推拉电子效应减弱,影响体系对太阳光的吸收利用,同时刚性共平面骨架加剧了分子间π-π堆积,引起染料聚集而加速载流子复合,从而影响其电池器件的开路电压(V_(oc))和J_(sc),不利于光伏性能的提升.
In this paper, the triphenylcarbazole, N-phenylcarbazole and indole [3,2,1-jk] carbazole as donors, respectively, 3,6,6- and 2,7- Cyanoacetic acid acceptor bond into two series of a total of 6 D-π-A dye molecules to study them as a photosensitizer dye-sensitized solar cell devices photovoltaic performance by comparison found that the same donor unit Of the dye molecules, the 2,7-linked carbazole π-bridge its π-electron delocalization of the conjugated backbone better than the 3,6-position, so that the intramolecular charge transfer absorption was significantly wider and (J_ (sc)) of the corresponding battery device is larger, which shows a higher photoelectric conversion efficiency; when the π-bridge is the same, the donor unit consists of triphenylamine Followed by conversion to N-phenylcarbazole and indole [3,2,1-jk] carbazole, with the direct bond between the benzene ring its molecule coplanarity enhancement, the nitrogen atom on the lone pair of electrons involved in conjugation , Which increases the π-electron delocalization of the conjugated skeleton of the donor unit, but leads to a decrease in the intramolecular push-pull electronic effect of the nitrogen atom alone, which affects the system’s absorption and utilization of sunlight, The rigid coplanar framework aggravates the π-π stacking of the molecules and causes the aggregation of the dyes to accelerate the carrier recombination, which affects the open circuit voltage (V oc) and J sc of the battery device, which is not conducive to the improvement of photovoltaic performance .