Optimizing the photocurrent efficiency of dye-sensitized solar cells through the controlled aggregation of chalcogenoxanthylium dyes on nanocrystalline titania films
Optimizing the photocurrent efficiency of dye-sensitized solar cells through the controlled aggregation of chalcogenoxanthylium dyes on nanocrystalline titania films
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DOI：
10.1021/jp803990b
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发表时间：
2008-08-28
影响因子：
3.7
通讯作者：
Watson, David F.
中科院分区：
文献类型：
--
作者：
Mann, Jonathan R.;Gannon, Michael K.;Watson, David F.
在染料敏化太阳能电池（DSSCs）中，硫原黄杂蒽染料作为纳米晶二氧化钛的敏化剂进行了表征。表征了4个系列染料：2,7-二（二甲氨基）-9-（2-噻基-5-羧基）硫基染料（I-E，其中E = 0， S, Se）；2,7-二（二甲氨基）-9-（3-噻吩-2-羧基）硫基黄嘌呤染料（2-E，其中E = S, Se）；2,7-二（二甲氨基）-9-（2-噻吩基）硒黄嘌呤染料（3-Se）；4-Se， 1-Se的约束模拟。染料的取向和聚集状态是通过改变表面附着基团相对于原核的位置来控制的。系列1染料和4-Se在二氧化钛表面发生h聚集，而系列2染料在无定形单分子层上吸附。（3-Se没有明显地吸附到二氧化钛薄膜上，这是由于缺乏系聚基团。）与吸附在非晶态单分子膜上的染料相比，h聚集染料具有更宽的吸收带、更高的光收集效率和更好的光电化学性能。系列1染料的最大入射光子电流效率（ipce）范围为70% ~ 84%，而2-S和2-Se的最大入射光子电流效率分别为11%和20%。研究结果表明，通过系统地改变染料的结构及其在表面的取向和聚集状态，可以优化含有有机染料的DSSCs的光收集效率、IPCE和吸收光子电流效率（APCE）。
Chalcogenoxanthylium dyes were characterized as sensitizers of nanocrystalline titania in dye-sensitized solar cells (DSSCs). Four series of dyes were characterized: 2,7-bis(dimethylamino)-9-(2-thienyl-5-carboxy)chalcogenoxanthylium dyes (I-E, where E = 0, S, Se); 2,7-bis(dimethylamino)-9-(3-thienyl-2-carboxy)chalcogenoxanthylium dyes (2-E, where E = S, Se); a 2,7-bis(dimethylamino)-9-(2-thienyl)selenoxanthylium dye (3-Se); 4-Se, a constrained analog of 1-Se. The orientation and aggregation state of the dyes were controlled by varying the position of the surface-attachment group relative to the xanthylium core. Series 1 dyes and 4-Se underwent H-aggregation on titania surfaces, whereas series 2 dyes adsorbed in amorphous monolayers. (3-Se did not adsorb appreciably to titania films, due to the lack of a tethering group.) The H-aggregated dyes exhibited broader absorption bands, increased light-harvesting efficiencies, and improved photoelectrochemical performance compared to the dyes which adsorbed in amorphous monolayers. The maximum incident photon-to-current efficiencies (IPCEs) of series I dyes ranged from 70% to 84%, whereas those of 2-S and 2-Se were 11% and 20%. Our findings reveal that the light-harvesting efficiency, IPCE, and absorbed photon-to-current efficiency (APCE) of DSSCs with organic dyes can be optimized by systematically varying the structure of the dyes and their orientation and aggregation state on the surface.