Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto 615-8510, Japan.
ChemSusChem. 2011 Jun 20;4(6):797-805. doi: 10.1002/cssc.201100029. Epub 2011 May 17.
5,10,15,20-Tetrakis(2,4,6-trimethylphenyl)-6'-carboxylquinoxalino[2,3-b]quinoxalino[12,13-b']porphyrinatozinc(II) (ZnPBQ) is synthesized to evaluate the effects of π elongation of quinoxaline-fused porphyrins on the optical, electrochemical, and photovoltaic properties. ZnPBQ showed an intensified Soret band as well as red-shifted Soret and Q bands relative to 5,10,15,20-tetrakis(2,4,6-trimethylphenyl)-6'-carboxylquinoxalino[2,3-b]porphyrinatozinc(II) (ZnPQ), demonstrating the improved light-harvesting property of ZnPBQ. The optical and electrochemical HOMO-LUMO gaps were consistent with those estimated by DFT calculations. The photovoltaic properties were compared under optimized conditions, in which a sealed device structure with TiCl(4) -treated, TiO(2) double layers was used. The ZnPBQ cell exhibited a relatively high power conversion efficiency (η) of 4.7%, which was smaller than that of the ZnPQ cell (η=6.3%). The weaker electronic coupling between the LUMO of ZnPBQ and conduction band (CB) of TiO(2) or more tilted geometry of ZnPBQ on the TiO(2) surface may result in the low electron injection/charge collection efficiency as well as the low incident photon-to-current efficiency (IPCE) for the ZnPBQ cell (maximum IPCE=56%) relative to the ZnPQ cell (maximum IPCE=75%), leading to the lower η value of the ZnPBQ cell than that of the ZnPQ cell. In addition, the open-circuit potential of the ZnPBQ cell also slightly decreased with the effect of charge recombination from the electrons injected into the CB of TiO(2) to I(3)(-).
5,10,15,20-四(2,4,6-三甲苯基)-6'-羧基喹喔啉[2,3-b]喹喔啉[12,13-b']卟啉锌(II)（ZnPBQ）被合成以评估喹喔啉稠合卟啉的π 伸长对光学、电化学和光伏性能的影响。与 5,10,15,20-四(2,4,6-三甲苯基)-6'-羧基喹喔啉[2,3-b]卟啉锌(II)（ZnPQ）相比，ZnPBQ 显示出增强的 Soret 带以及红移的 Soret 和 Q 带，表明 ZnPBQ 具有改善的光捕获性能。光学和电化学 HOMO-LUMO 能隙与通过 DFT 计算估计的值一致。在优化条件下比较了光伏性能，其中使用了用 TiCl(4)处理的 TiO(2)双层的密封器件结构。ZnPBQ 电池表现出相对较高的功率转换效率（η）为 4.7%，小于 ZnPQ 电池（η=6.3%）。ZnPBQ 上的 LUMO 与 TiO(2)的导带（CB）之间较弱的电子耦合或更倾斜的 ZnPBQ 几何形状可能导致电子注入/电荷收集效率较低以及入射光子电流效率（IPCE）较低 ZnPBQ 电池（最大 IPCE=56%）相对于 ZnPQ 电池（最大 IPCE=75%），导致 ZnPBQ 电池的 η 值低于 ZnPQ 电池。此外，ZnPBQ 电池的开路电位也略有降低，这是由于电子注入 TiO(2)的 CB 到 I(3)(-)的电荷复合的影响。
