Global GET-Future Laboratory and Department of Advanced Materials Chemistry, Korea University, 2511 Sejong-ro, Jochiwon, Sejong 339-700 (Korea), Fax: (+82) 44-860-1739.
Chemistry. 2013 Nov 11;19(46):15545-55. doi: 10.1002/chem.201301658. Epub 2013 Sep 23.
The Y-shaped, low molecular mass, hole-conductor (HC), acidic coadsorbents 4-{3,7-bis[4-(2-ethylhexyloxy)phenyl]-10H-phenothiazin-10-yl}benzoic acid (PTZ1) and 4-{3,7-bis[4-(2-ethylhexyloxy)phenyl]-10H-phenothiazin-10-yl}biphenyl-4-carboxylic acid (PTZ2) were developed. Owing to their tuned and negative-shifted HOMO levels (vs. NHE), they were used as HC coadsorbents in dye-sensitized solar cells (DSSCs) to improve cell performance through desired cascade-type hole-transfer processes. Their detailed functions as HC coadsorbents in DSSCs were investigated to obtain evidence for the desired cascade-type hole-transfer processes. They have multiple functions, such as preventing π-π stacking of dye molecules, harvesting light of shorter wavelengths, and faster dye regeneration. By using PTZ2 as the tailor-made HC coadsorbent on the TiO2 surface with the organic dye NKX2677, an extremely high conversion efficiency of 8.95 % was achieved under 100 mW cm(-2) AM 1.5G simulated light (short-circuit current JSC =16.56 mA cm(-2) , open-circuit voltage VOC =740 mV, and fill factor of 73 %). Moreover, JSC was increased by 13 %, VOC by 27 % and power-conversion efficiency by 49 % in comparison to an NKX2677-based DSSC without an HC coadsorbent. This is due to the HC coadsorbent having a HOMO energy level well matched to that of the NKX-2677 dye to induce the desired cascade-type hole-transfer processes, which are associated with a slower charge recombination, fast dye regeneration, effective screening of liquid electrolytes, and an induced negative shift of the quasi-Fermi level of the electrode. Thus, this new class of Y-shaped, low molecular weight, organic, HC coadsorbents based on phenothiazine carboxylic acid derivatives hold promise for highly efficient organic DSSCs.
开发了 Y 形低分子量空穴传输（HC）酸性共吸附剂 4-{3,7-双[4-(2-乙基己氧基)苯基]-10H-吩噻嗪-10-基}苯甲酸（PTZ1）和 4-{3,7-双[4-(2-乙基己氧基)苯基]-10H-吩噻嗪-10-基}联苯-4-羧酸（PTZ2）。由于其调整后的和负位移的 HOMO 能级（相对于 NHE），它们被用作染料敏化太阳能电池（DSSC）中的 HC 共吸附剂，通过所需的级联型空穴转移过程来提高电池性能。研究了它们作为 DSSC 中 HC 共吸附剂的详细功能，以获得所需级联型空穴转移过程的证据。它们具有多种功能，例如防止染料分子的 π-π 堆积、收集较短波长的光以及更快的染料再生。通过使用 PTZ2 作为 TiO2 表面的定制 HC 共吸附剂与有机染料 NKX2677 一起使用，在 100 mW cm(-2) AM 1.5G 模拟光下（短路电流 JSC =16.56 mA cm(-2) ，开路电压 VOC =740 mV，填充因子为 73%），实现了 8.95%的极高转换效率。此外，与没有 HC 共吸附剂的基于 NKX2677 的 DSSC 相比，JSC 增加了 13%，VOC 增加了 27%，功率转换效率增加了 49%。这是由于 HC 共吸附剂的 HOMO 能级与 NKX-2677 染料非常匹配，从而诱导所需的级联型空穴转移过程，这与较慢的电荷复合、快速的染料再生、有效屏蔽液体电解质以及电极准费米能级的诱导负位移有关。因此，基于吩噻嗪羧酸衍生物的这种新型 Y 形低分子量有机 HC 共吸附剂有望用于高效有机 DSSC。
