Synthesis of sterically hindered phthalocyanines and their applications to dye-sensitized solar cells
Synthesis of sterically hindered phthalocyanines and their applications to dye-sensitized solar cells
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DOI：
10.1039/b803272f
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发表时间：
2008-10-28
影响因子：
4
通讯作者：
Imahori, Hiroshi
中科院分区：
文献类型：
--
作者：
Eu, Seunghun;Katoh, Takashi;Imahori, Hiroshi
具有高周边取代度且不受区域异构体潜在污染的酞菁已被合成并评估为染料敏化太阳能电池应用的光敏剂。每种位阻前体化合物都是通过与芳基氯和相应的硼酸进行铃木-宫浦交叉偶联反应来实现的。与 TiO2 的导带相比，无金属酞菁敏化太阳能电池由于其激发单线态 (LUMO) 较低，因此没有显示出光电流产生。锌金属化后，酞菁的 LUMO 能级被推高，这种变化为电子注入提供了放能自由能变化。锌酞菁敏化太阳能电池在近红外区域表现出0.57%的功率转换效率(eta)和4.9%的最大IPCE。更重要的是，在存在和不存在鹅去氧胆酸的情况下制备的电池显示出功率转换效率没有差异。这意味着众所周知的酞菁聚集趋势被认为可以增强酞菁激发单线态的自猝灭，而高取代度有效地抑制了该聚集趋势。电子注入的驱动力以及染料核与 TiO2 表面之间的距离对于设计高性能酞菁光敏剂也具有重要意义。
Phthalocynanies with high periphearl substitutions and free from potential contamination by regioisomers have been synthesized and evaluated as photosensitizers for dye-sensitized solar cell applications. Each of the sterically hindered precursor compounds was accomplished by Suzuki-Miyaura cross-coupling reactions with the arylchloride and corresponding boronic acids. Metal free phthalocyanine-sensitized solar cells showed no photocurrent generation due to its low excited singlet state (LUMO) compared with the conduction band of TiO2. Upon zinc metalation, the LUMO level of the phthalocyanine was pushed up, and this variation afforded an exergonic free energy change for electron injection. the zinc phthalocyanine-sensitized solar cell displayed 0.57% power conversion efficiency (eta) and 4.9% maximal IPCE in the near infrared region. More importantly, the cell prepared with and without the presence of chenodeoxycholic acid revealed no difference in the power conversion efficiency. This implies that the well-known aggregation tendency of phthalocyanines that is considered to enhance the self-quenching of the phthalocyanine excited singlet state is effectively suppressed by the high degree of substitutions. The significance of the driving force for electron injection and the distance between the dye core and the TiO2 surface is also highlighted for devising high performance phthalocyanine photosensitizers.