New Ï-extended porphyrin dyes YD26âYD29 with long alkoxyl chains at the ortho positions of the meso-phenyls, and meta di-tert-butylphenyl-substituted porphyrins YD12âCN, and YD13âCN were synthesized for dye-sensitized solar cells, and their optical, electrochemical and photovoltaic properties were investigated and compared with those of YD12 and YD13. The absorption spectra of YD26âYD29 showed a slight red shift of Soret bands and blue shift of Q bands as compared to the meta-substituted porphyrins due to the electron-donating effects of dioctyloxy substituents at the ortho-positions of the meso-phenyl rings. Replacement of the carboxyl with a cyanoacrylic acid as the anchoring group results in significant broadening and red shifts of the absorptions, which is due to the strong electronic coupling between the pull unit and the porphyrin ring facilitated by the CC triple bond. The electrochemical studies and quantum-chemical calculations (DFT) indicated that the ortho alkoxy-substituted sensitizers exhibit lower oxidation potential, i.e. a higher HOMO energy level, and their HOMOâLUMO gaps are comparable to the meta-substituted analogues. The photovoltaic measurements confirmed that the ortho-octyloxy groups in the two meso-phenyls of YD26 and YD27 play a significant role in preventing dye aggregation thereby enhancing the corresponding short-circuit current density and open-circuit voltage. The power conversion efficiency (η) of YD26 is 8.04%, which is 11% higher than that of YD12, whereas the efficiency of YD27 is 6.03%, which is 135% higher than that of YD13. On the other hand, the poor performance of YD28 and YD29 is due to the floppy structural nature and limited molecular rigidity of the cyanoacrylic acid anchor.
合成了中
苯基正交位置具有长烷
氧基链的Ï-延伸
卟啉新
染料YD26âYD29和元二
叔丁基苯基取代
卟啉YD12âCN和YD13âCN,用于
染料敏化太阳能电池,研究了它们的光学、电
化学和光伏特性,并与YD12和YD13进行了比较。与元取代
卟啉相比,YD26âYD29 的吸收光谱显示出轻微的索雷特带红移和 Q 带蓝移,这是由于二辛基
氧基取代基在中位
苯基环的正交位置上具有电子捐赠效应。用
氰基
丙烯酸取代羧基作为锚定基团会导致吸收的显著拓宽和红移,这是由于 CC 三键促进了拉伸单元与
卟啉环之间的强电子耦合。电
化学研究和量子
化学计算(DFT)表明,正烷
氧基取代的敏化剂具有较低的
氧化电位,即较高的 HO
MO 能级,其 HO
MOâLU
MO 间隙与元取代的类似物相当。光电测量结果证实,YD26 和 YD27 的两个中
苯基中的
正辛氧基在防止
染料聚集方面发挥了重要作用,从而提高了相应的短路电流密度和开路电压。YD26 的功率转换效率(δ-)为 8.04%,比 YD12 高 11%,而 YD27 的效率为 6.03%,比 YD13 高 135%。另一方面,YD28 和 YD29 的性能较差是由于
氰基
丙烯酸锚的结构性质较软,分子刚性有限。