Wide-Range Near-Infrared Sensitizing 1H-Benzo[c,d]indol-2-ylidene-Based Squaraine Dyes for Dye-Sensitized Solar Cells
Wide-Range Near-Infrared Sensitizing 1H-Benzo[c,d]indol-2-ylidene-Based Squaraine Dyes for Dye-Sensitized Solar Cells
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DOI：
10.1021/acs.joc.8b00070
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发表时间：
2018-04-20
影响因子：
3.6
通讯作者：
Matsui, Masaki
中科院分区：
文献类型：
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作者：
Haishima, Yuki;Kubota, Yasuhiro;Matsui, Masaki
设计了以1h -苯并[c，d]吲哚-2-吡啶为供体部分的近红外吸收方碱染料SQ1-SQ7，用于DSSCs。苯环环成3h -吲哚基锚基团导致TiO2薄膜上的吸收带红移和变宽，这反映在与非苯融合衍生物SQ1 （4.39 mA cm(-2)）相比，SQ2的短路电流密度提高了6.22 mA cm（-2）。虽然在h -苯并[c，d]吲哚-2-吡啶基供体部分上引入丁氧基（SQ4: 806 nm）或二氨基基（SQ5-SQ7: 815-820 nm）导致乙醇中吸收最大值红移，但与非取代衍生物SQ2 （784 nm）相比，SQ4- sq7的HOMO能级与I-/I-3（-）的氧化还原电位产生了不理想的近似。因此，丁基（SQ4: 0.56）和二氨基（SQ5-SQ7: 0.25-0.30）衍生物的转化效率相对较低。由于2-乙基己基衍生物SQ3表现出红移吸收（λ (max): 796 nm），合适的HOMO和LUMO能级，以及相对有效的电荷重组限制，该染料实现了最高的转换效率（1.31%），在640 - 860 nm的宽范围内具有超过20%的高IPCE响应，并在1000 nm处发生IPCE。
NIR absorbing squaraine dyes SQ1-SQ7 having 1H-benzo[c,d]indol-2-ylidene as a donor moiety were designed for application in DSSCs. Annulation of the benzene ring to an 3H-indolium-based anchor moiety led to a red-shifted and broadened absorption band on TiO2 film, which were reflected in the improved short-circuit current density of SQ2 (6.22 mA cm(-2)) compared to the nonbenzene fused derivative SQ1 (4.39 mA cm(-2)). Although the introduction of a butoxy (SQ4: 806 nm) or dialkylamino group (SQ5-SQ7: 815-820 nm) to the 1H-benzo[c,d]indol-2-ylidene-based donor moiety resulted in red-shifted absorption maxima in ethanol compared to the nonsubstituted derivative SQ2 (784 nm), the HOMO energy level of SQ4-SQ7 gave rise to an undesirable approximation to the redox potential of I-/I-3(-). Thus, the butoxy (SQ4: 0.56) and dialkylamino (SQ5-SQ7: 0.25-0.30) derivatives had relatively lower conversion efficiencies. Since the 2-ethylhexyl derivative SQ3 exhibited red-shifted absorption (lambda(max): 796 nm), suitable HOMO and LUMO energy levels, and relatively efficient restriction of charge recombination, this dye achieved the highest conversion efficiency (1.31%), along with a high IPCE response of over 20% over a wide range from 640 to 860 nm and an onset of IPCE at 1000 nm.