Indoline (In) and aniline (An) donor-based visible light active unsymmetrical squaraine (SQ) dyes were synthesized for dye-sensitized solar cells (DSSCs), where the position of An and In units was changed with respect to the anchoring group (carboxylic acid) to have In-SQ-An-CO₂H and An-SQ-In-CO₂H sensitizers, AS1–AS5. Linear or branched alkyl groups were functionalized with the N atom of either In or An units to control the aggregation of the dyes on TiO₂. AS1–AS5 exhibit an isomeric π-framework where the squaric acid unit is placed in the middle, where AS2 and AS5 dyes possess the anchoring group connected with the An donor, and AS1, AS3, and AS4 dyes having the anchoring group connected with the In donor. Hence, the conjugation between the middle squaric acid acceptor unit and the anchoring −CO₂H group is short for AS2, AS5, and AK2 and longer for AS1, AS3, and AS4 dyes. AS dyes showed absorption between 501 and 535 nm with extinction coefficients of 1.46–1.61 × 10⁵ M^–1 cm^–1. Further, the isomeric π-framework of An-SQ-In-CO₂H and In-SQ-An-CO₂H exhibited by means of changing the position of In and An units a bathochromic shift in the absorption properties of AS2 and AS5 compared to the AS1, AS3, and AS4 dyes. The DSSC device fabricated with the dyes contains short acceptor-anchoring group distance (AS2 and AS5) showed high photovoltaic performances compared to the dyes having longer distance (AS1, AS3, and AS4) with the iodolyte (I^–/I₃^–) electrolyte. DSSC device efficiencies of 5.49, 6.34, 6.16, and 5.57% have been achieved for AS1, AS2, AS3, and AS4 dyes, respectively; without chenodeoxycholic acid (CDCA), small changes have been observed in the device performance of the AS dyes with CDCA. Significant changes have been noted in the DSSC parameters (open-circuit voltage V_OC, short-circuit current J_SC, fill factor ff, and efficiency η) for the AS5 dye while sensitized with CDCA and showed highest DSSC efficiency of 8.01% in the AS dye series. This study revealed the potential of shorter SQ acceptor-anchoring group distance over the longer one and the importance of alkyl groups on the overall DSSC device performance for the unsymmetrical squaraine dyes.

中文翻译：

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供体单元和烷基的位置对染料敏化太阳能电池器件性能的影响：基于二氢吲哚-苯胺供体的可见光活性不对称方酸菁染料

合成了基于二氢吲哚 (In) 和苯胺 (An) 供体的可见光活性不对称方酸菁 (SQ) 染料，用于染料敏化太阳能电池 (DSSC)，其中 An 和 In 单元相对于锚定基团的位置发生了变化。羧酸）以具有 In-SQ-An-CO ₂ H 和 An-SQ-In-CO ₂ H 敏化剂AS1–AS5。直链或支链烷基基团用In或An单元的N原子官能化以控制染料在TiO ₂上的聚集。AS1–AS5呈现异构 π 骨架，其中方酸单元位于中间，其中AS2和AS5染料具有与 An 供体连接的锚定基团，而AS1、AS3和AS4染料具有与 An 供体连接的锚定基团。在捐助者。因此，中间方酸受体单元和锚定-CO _{2 H基团之间的缀合对于}AS2、AS5和AK2来说较短，而对于AS1、AS3和AS4染料来说较长。 AS染料在501和535 nm之间有吸收，消光系数为1.46–1.61 × 10 ⁵ M ^–1 cm ^–1。此外，An-SQ-In-CO ₂ H和In-SQ-An-CO ₂ H的异构π骨架通过改变In和An单元的位置表现出AS2和AS5的吸收特性的红移。与AS1、AS3和AS4染料相比。与具有较长距离的染料（AS1、AS3和AS4）以及碘电解质（I ^- /I ₃ ^{- ）电解质相比，使用包含短受体锚定基团距离（} AS2和AS5 ）的染料制造的DSSC器件表现出较高的光伏性能。对于AS1、AS2、AS3和AS4染料，DSSC 装置效率分别达到 5.49%、6.34%、6.16% 和 5.57% ；在没有鹅去氧胆酸 (CDCA) 的情况下，在含有 CDCA 的AS染料的器件性能中观察到了微小的变化。 DSSC 参数（开路电压VOC _、短路电流J _{SC）发生了显着变化}使用 CDCA 敏化时AS5染料的 、填充因子 ff 和效率 η)，并在AS染料系列中显示出最高的 DSSC 效率 8.01%。这项研究揭示了较短的 SQ 受体锚定基团距离相对于较长的 SQ 受体锚定基团距离的潜力，以及烷基基团对不对称方酸菁染料的整体 DSSC 器件性能的重要性。