Bessho Takeru, Yoneda Eiji, Yum Jun-Ho, Guglielmi Matteo, Tavernelli Ivano, Imai Hachiro, Rothlisberger Ursula, Nazeeruddin Mohammad K, Grätzel Michael
Laboratory for Photonics and Interfaces, Swiss Federal Institute of Technology, CH - 1015 Lausanne, Switzerland.
J Am Chem Soc. 2009 Apr 29;131(16):5930-4. doi: 10.1021/ja9002684.
A novel thiocyanate-free cyclometalleted ruthenium sensitizer for solar cells is designed and developed. Upon anchoring to nanocrystalline TiO(2) films, it exhibits a remarkable incident monochromatic photon-to-current conversion efficiency of 83%. The solar cell employing a liquid-based electrolyte exhibits a short circuit photocurrent density of 17 mA/cm(2), an open circuit voltage of 800 mV, and a fill factor of 0.74, corresponding to an overall conversion efficiency of 10.1% at standard AM 1.5 sunlight. To understand the structural, electronic, and optical properties of the cyclometalleted ruthenium sensitizer, we have investigated using density functional theory (DFT) and time-dependent DFT (TDDFT). Our results show the HOMO is located mostly on ruthenium and cyclometalated ligand, while the LUMO is on 4-carboxylic acid-4'-carboxylate-2,2'-bipyridine. Molecular orbitals analysis confirmed the experimental assignment of redox potentials, and TDDFT calculations allowed assignment of the visible absorption bands. The present findings provide new design criteria for the next generation of ruthenium sensitizers and help foster widespread interest in the engineering of new sensitizers that interact effectively with the I(-)/I(3)(-) redox couple.
设计并开发了一种用于太阳能电池的新型无硫氰酸根环金属化钌敏化剂。将其锚定在纳米晶TiO(2)薄膜上后，它展现出83%的显著单色入射光子-电流转换效率。采用基于液体电解质的太阳能电池具有17 mA/cm(2)的短路光电流密度、800 mV的开路电压和0.74的填充因子，在标准AM 1.5太阳光下对应的总转换效率为10.1%。为了解环金属化钌敏化剂的结构、电子和光学性质，我们使用密度泛函理论（DFT）和含时密度泛函理论（TDDFT）进行了研究。我们的结果表明，最高占据分子轨道（HOMO）主要位于钌和环金属化配体上，而最低未占据分子轨道（LUMO）位于4-羧酸-4'-羧酸盐-2,2'-联吡啶上。分子轨道分析证实了氧化还原电位的实验归属，并且TDDFT计算确定了可见吸收带。目前的研究结果为下一代钌敏化剂提供了新的设计标准，并有助于激发人们对与I(-)/I(3)(-)氧化还原对有效相互作用的新型敏化剂工程的广泛兴趣。
