Heteroleptic Ru(II) cyclometalated complexes derived from benzimidazole-phenyl carbene ligands for dye-sensitized solar cells: an experimental and theoretical approach
Heteroleptic Ru(II) cyclometalated complexes derived from benzimidazole-phenyl carbene ligands for dye-sensitized solar cells: an experimental and theoretical approach
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DOI：
10.1039/c6qm00264a
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发表时间：
2017-05-01
影响因子：
7
通讯作者：
Guptae, Ravindra Kumar
中科院分区：
文献类型：
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作者：
Jella, Tejaswi;Srikanth, Malladi;Guptae, Ravindra Kumar
我们设计并合成了两个新的基于N-杂配体/苯基卡宾（NH-苯基C）的配体，1-苄基-2-（3，5-双（三氟甲基）苯基）-1H-苯并[d]咪唑（L1）和3-（1-苄基-1H-苯并-2-基）-10-己基-10-H-吩噻嗪（L2），用作染料敏化太阳能电池的杂配体Ru（II）配合物的辅助配体。N719敏化剂的两个NCS基团被L1（TC-1）和L2（TC-3）取代以获得环化的Ru（II）配合物，并且4，4 '-二羧基-2，2'-联吡啶（dcbpy）中的一个被L1取代以获得混配Ru（II）配合物（TC-2）。两个三氟甲基基团的L1配体的存在下稳定的钌（II）络合物的HOMO水平和吩噻嗪部分的L2配体的存在下改变的TC-3络合物的吸收特性。通过元素分析、ESI-MS、H-1 NMR、吸收和发射光谱以及电化学方法对配体和混配Ru（II）配合物进行了表征。与标准N719敏化剂相比，TC-1和TC-3的吸收光谱发生蓝移。这些新设计的环化和混配钌（II）配合物的评估显示，TC-2表现出的效率为7.63%，而TC-1的效率为6.39%，使用I-/I-3（-）氧化还原对。DFT和纳秒瞬态吸收动力学研究已被用来了解TC-3复合物的低效率。
We have designed and synthesized two new ligands based on N-heteroleptic/phenyl carbene (NH-phenyl C) i.e., 1-benzyl-2-(3,5-bis(trifluoromethyl)phenyl)-1H-benzo[d]imidazole (L1) and 3-(1-benzyl-1H-benzol-2-yl)-10-hexyl-10-H-phenothiazene (L2), used as ancillary ligands to heteroleptic Ru(II) complexes for dyesensitized solar cells. Both NCS groups of the N719 sensitizer are replaced with L1 (TC-1) and L2 (TC-3) to obtain cyclometalated Ru(II) complexes and one of 4,4'-dicarboxylato-2,2'-bipyridine (dcbpy) with L1 to obtain a heteroleptic Ru(II) complex (TC-2). The presence of two trifluoromethyl groups of the L1 ligand stabilizes the HOMO level of Ru(II) complexes and the presence of a phenothiazine moiety of the L2 ligand alters the absorption properties of the TC-3 complex. Both the ligands and the heteroleptic Ru(II) complexes are characterized by elemental analyses, ESI-MS, H-1 NMR, absorption and emission spectroscopy as well as electrochemical methods. The absorption spectra of TC-1 and TC-3 are blue shifted, when compared to the standard N719 sensitizer. The assessment of these newly designed cyclometalated and heteroleptic Ru(II) complexes has revealed that TC-2 exhibits an efficiency of 7.63%, whereas TC-1 has an efficiency of 6.39% using an I-/I-3(-) redox couple. DFT and nanosecond transient absorption kinetic studies have been adopted to understand the low efficiency of the TC-3 complex.