Influence of Surface-Attachment Functionality on the Aggregation, Persistence, and Electron-Transfer Reactivity of Chalcogenorhodamine Dyes on TiO2
Influence of Surface-Attachment Functionality on the Aggregation, Persistence, and Electron-Transfer Reactivity of Chalcogenorhodamine Dyes on TiO2
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DOI：
10.1021/la300668k
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发表时间：
2012-05-01
期刊：
影响因子：
3.9
通讯作者：
Detty, Michael R.
中科院分区：
文献类型：
--
作者：
Mulhern, Kacie R.;Orchard, Alexandra;Detty, Michael R.
将含有膦酸和羧酸的硫属罗丹明染料作为纳米晶 TiO2 敏化剂在染料敏化太阳能电池 (DSSC) 中进行比较。这些染料围绕 3,6-双（二甲氨基）硫属氧杂蒽鎓核心构建，并具有 9 个取代基：染料 1-E（E = O，Se）中的 5-羧基噻吩-2-基，染料 2-E（E = O，S）中的 4-羧基苯基，染料 3-E（E = O，Se）中的 5-膦酰基噻吩-2-基，以及 染料 4-E (E = O, Se) 中的 4-膦酰基苯基。所有染料均以 H 聚集体和单体的混合物形式吸附在 TiO2 上，相对于纯非晶单层的吸收光谱表现出更宽的吸收光谱。染料的表面覆盖率和 H 聚集程度随表面附着功能、9-芳基结构和硫族杂原子的性质变化最小，羧酸功能化染料 1-E 和 2-E 快速且完全地从 TiO2 解吸到酸化 CH3CN，但膦酸功能化染料 3-E 和 4-E 在 TiO2 上持续存在 天。 DSSCs的短路光电流作用光谱与染料功能化薄膜的吸收光谱密切对应；因此，H聚集不会降低电子注入产率或电荷收集效率。 DSSC 的最大单色入射光子电流效率 (IPCE) 范围为 53% 至 95%，并且羧酸功能化染料 1-E 和 2-E 的最高单色入射光子电流效率 (IPCE) 略高。白光照明下 DSSC 的功率转换效率较低（
Chalcogenorhodamine dyes bearing phosphonic acids and carboxylic acids were compared as sensitizers of nanocrystalline TiO2 in dye-sensitized solar cells (DSSCs). The dyes were constructed around a 3,6-bis(dimethylamino)chalcogenoxanthylium core and varied in the 9 substituent: 5-carboxythien-2-yl in dyes 1-E (E = O, Se), 4-carboxyphenyl in dyes 2-E (E = O, S), 5-phosphonothien-2-yl in dyes 3-E (E = O, Se), and 4-phosphonophenyl in dyes 4-E (E = O, Se). All dyes adsorbed to TiO2 as mixtures of H aggregates and monomers, which exhibited broadened absorption spectra relative to those of purely amorphous monolayers. Surface coverages of dyes and the extent of H aggregation varied minimally with the surface-attachment functionality, the structure of the 9-aryl group, and the identity of the chalcogen heteroatom, Carboxylic acid-functionalized dyes 1-E and 2-E desorbed rapidly and completely from TiO2 into acidified CH3CN, but phosphonic acid-functionalized dyes 3-E and 4-E persisted on TiO2 for days. Short-circuit photocurrent action spectra of DSSCs corresponded Closely to the absorptance spectra of dye-functionalized films; thus, H aggregation did not decrease the electron-injection yield or charge-collection efficiency. Maximum monochromatic incident photon-to-current efficiencies (IPCEs) of DSSCs ranged from 53 to 95% and were slightly higher for carboxylic acid-functionalized dyes 1-E and 2-E. Power-conversion efficiencies of DSSCs under white-light illumination were low (