A novel ladderlike fused-ring donor, dithienocyclopentacarbazole (DTCC) derivative, is used to design and synthesize three novel donor-acceptor-π-acceptor-type organic dyes (C1-C3) via facile direct arylation reactions, in which the DTCC derivative substituted by four p-octyloxyphenyl groups is served as the electron donor and the carboxylic acid group is used as the electron acceptor or anchoring group. To fine-tune the optical, electrochemical, and photovoltaic properties of the three dyes, various auxiliary acceptors, including benzo[2,1,3]thiadiazole (BT), 5,6-difluorobenzo[2,1,3]thiadiazole (DFBT), and pyridal[2,1,3]thiadiazole (PT), are incorporated into the dye backbones. The results indicate that all of the three dyes exhibit strong light-capturing ability in the visible region and obtain relatively high molar extinction coefficients (>31 000 M-1 cm-1) due to their strong charge transfer (CT) from donor to acceptor. Moreover, theoretical model calculations demonstrate fully separated highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels for the three dyes, which is helpful for efficient charge separation and electron injection. Using the three dyes as sensitizers, conventional dye-sensitized solar cells (DSSCs) based on liquid iodide/triiodide redox electrolytes are fabricated. Our results indicate that the BT-containing dye C1 affords the highest power conversion efficiency of up to 6.75%, much higher than that of the DFBT-containing dye C2 (5.40%) and the PT-containing dye C3 (1.85%). To our knowledge, this is the first example reported in the literature where the DTCC unit has been used to develop novel organic dyes for DSSC applications. Our work unambiguously demonstrates that the ladderlike DTCC derivatives are the superb electron-donating blocks for the development of high-performance organic dyes.

中文翻译：

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新型DA-π-A型有机染料，包含梯形二硫杂环戊环咔唑供体，可用于有效的染料敏化太阳能电池。

一种新颖的梯状稠环供体二噻吩并环戊咔唑（DTCC）衍生物用于通过容易的直接芳基化反应设计和合成三种新颖的供体-受体-π-受体型有机染料（C1-C3），其中DTCC衍生物被取代四个对-辛基氧基苯基基团用作电子给体，而羧酸基团用作电子受体或锚定基团。要微调这三种染料的光学，电化学和光电性质，可以使用各种辅助受体，包括苯并[2,1,3]噻二唑（BT），5,6-二氟苯并[2,1,3]噻二唑（DFBT） ）和吡啶并[2,1,3]噻二唑（PT）被并入染料骨架。结果表明，这三种染料均在可见光区具有很强的捕获光的能力，并具有较高的摩尔消光系数（> 31 000 M-1 cm-1），因为它们从施主到受主的强电荷转移（CT）。此外，理论模型计算表明三种染料完全分离的最高占据分子轨道和最低未占据分子轨道能级，这有助于有效的电荷分离和电子注入。使用这三种染料作为敏化剂，可以制备基于液态碘化物/三碘化物氧化还原电解质的常规染料敏化太阳能电池（DSSC）。我们的结果表明，含BT的染料C1提供高达6.75％的最高功率转换效率，远高于含DFBT的染料C2（5.40％）和含PT的染料C3（1.85％）。据我们所知，这是文献中报道的第一个例子，其中DTCC单元已被用于开发用于DSSC应用的新型有机染料。