Engineering of efficient panchromatic sensitizers for nanocrystalline TiO2-based solar cells
Engineering of efficient panchromatic sensitizers for nanocrystalline TiO2-based solar cells
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DOI：
10.1021/ja003299u
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发表时间：
2001-02-28
影响因子：
15
通讯作者：
Grätzel, M
中科院分区：
文献类型：
--
作者：
Nazeeruddin, MK;Péchy, P;Grätzel, M
本文报道了一系列由三硫氰基钌（II）的羧基三联吡啶配合物衍生的全色钌（II）敏化剂。含有不同质子化程度的黑色染料{（C2 H5）（3）NH}[Ru（H（3）tcterpy）（NCS）（3）] 1，{（C4 H9）（4）N}（2）[Ru（H（2）tcterpy）（NCS）（3）] 2，{（C4 H9）（4）N}（3）[Ru（H（2）tcterpy）（NCS）合成了[（Htcterpy）（NCS）（3）] 3和{（C4 H9）（4）N}（4）[Ru（tcterpy）（NCS）（3）] 4（tcterpy = 4，4 '，4“-tricarboxy-2，2'：6 '，2“-terpyridine），并通过紫外-可见光谱、发射光谱、红外光谱、拉曼光谱、核磁共振谱、循环伏安法和X-射线衍射对其进行了表征。配合物2的晶体结构证实了存在的Ru（II）N6中心核心来自三联吡啶配体和三个N-键合的硫氰酸酯。相邻三联吡啶上的羧酸酯之间的分子间氢键产生2-D氢键阵列。的黑色染料的吸收和发射的最大值示出了红移与pH值的降低，并表现出pH值依赖的激发态寿命。发射最大值的红移是由于酸形式的更好的π受体性质，其降低了CT激发态的能量。由于硫氰酸根配体的存在，低能金属-配体电荷转移吸收带显示出明显的溶剂化变色。黑色染料的Ru（II）/（III）氧化电位和基于配体的还原电位随着质子数的减少而阴极移动，并且表现出更可逆的特性。配合物3在透明TiO 2薄膜上的吸附符合Langmuir等温线，吸附平衡常数K-ads为（1.0 +/- 0.3）× 10（5）M-1。在单层饱和时吸附的染料的量为（n（alpha）= 6.9 +/- 0.3）× 10（-8）mol/mg TiO 2，这比顺式-二（硫氰酸根合）双（2，2 '-联吡啶-4，4'-二羧酸酯）-钌（II）络合物的量少约30%。黑色染料，当锚定到纳米晶体;二氧化钛。薄膜在整个可见光范围内实现了非常有效的敏化，延伸到近红外区域高达920 nm，产生超过80%的入射光子电流效率（IPCE）。通过光伏校准实验室（NREL，U.S.A.）以确定它们在标准AM 1.5阳光下的太阳能-电力转换效率。得到的短路光电流密度为20.5mA/cm（2），开路电压为0.72V，对应于10.4%的总转换效率。
A new series of panchromatic ruthenium(II) sensitizers derived from carboxylated terpyridyl complexes of tris-thiocyanato Ru(II) have been developed. Black dye containing different degrees of protonation {(C2H5)(3)NH}[Ru(H(3)tcterpy)(NCS)(3)] 1, {(C4H9)(4)N}(2)[Ru(H(2)tcterpy)(NCS)(3)] 2, {(C4H9)(4)N}(3)[RU(Htcterpy)(NCS)(3)] 3, and {(C4H9)(4)N}(4)[Ru(tcterpy)(NCS)(3)] 4 (tcterpy = 4,4',4 " -tricarboxy-2,2':6',2 " -terpyridine) have been synthesized and fully characterized by UV-vis, emission, IR, Raman, NMR, cyclic voltammetry, and X-ray diffraction studies. The crystal structure of complex 2 confirms the presence of a Ru(II)N6 central core derived from the terpyridine ligand and three N-bonded thiocyanates. Intermolecular H-bonding between carboxylates on neighboring terpyridines gives rise to 2-D H-bonded arrays. The absorption and emission maxima of the black dye show a bathochromic shift with decreasing pH and exhibit pH-dependent excited-state lifetimes. The red-shift of the emission maxima is due to better pi -acceptor properties of the acid form that lowers the energy of the CT excited state. The low-energy metal-to-ligand charge-transfer absorption band showed marked solvatochromism due to the presence of thiocyanate ligands. The Ru(II)/(III) oxidation potential of the black dye and the ligand-based reduction potential shifted cathodically with decreasing number of protons and showed more reversible character. The adsorption of complex 3 from methoxyacetonitrile solution onto transparent TiO2 films was interpreted by a Langmuir isotherm yielding an adsorption equilibrium constant, K-ads, of (1.0 +/- 0.3) x 10(5) M-1. The amount of dye adsorbed at monolayer saturation was (n(alpha) = 6.9 +/- 0.3) x 10(-8) mol/mg of TiO2, which is around 30% less than that of the cis-di(thiocyanato)bis(2,2'-bipyridyl-4,4'-dicarboxylate)-ruthenium(II) complex. The black dye, when anchored to nanocrystalline;TiO2. films achieves very efficient sensitization over the whole visible range extending into the near-IR region up to 920 nm, yielding over 80% incident photon to-current efficiencies (IPCE). solar cells containing the black dye were subjected to analysis by a photovoltaic calibration laboratory (NREL, U.S.A.) to determine their solar-to-electric conversion efficiency under standard AM 1.5 sunlight. A short circuit photocurrent density obtained was 20.5 mA/cm(2), and the open circuit voltage was 0.72 V corresponding to an overall conversion efficiency of 10.4%.