Ruthenium and Osmium Complexes That Bear Functional Azolate Chelates for Dye-Sensitized Solar Cells

• Published in: Chemistry, an Asian journal Vol. 10; no. 5; pp. 1098 - 1115
• Main Authors: Chi, Yun, Wu, Kuan-Lin, Wei, Tzu-Chien
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.05.2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: chelates; Chemistry; Diodes; osmium; R&D; Research & development; ruthenium; sensitizers; solar cells; Solar energy; chelates; ruthenium; osmium; solar cells; sensitizers
• ISSN: 1861-4728; 1861-471X
• DOI: 10.1002/asia.201403261

The preparation of sensitizers for dye‐sensitized solar cells (DSSCs) represents an active area of research for both sustainability and renewable energy. Both RuII and OsII metal sensitizers offer unique photophysical and electrochemical properties that arise from the intrinsic electronic properties, that is, the higher propensity to form the lower‐energy metal‐to‐ligand charge‐transfer (MLCT) transition, and their capability to support chelates with multiple carboxy groups, which serve as a bridge to the metal oxide and enable efficient injection of the photoelectron. Here we present an overview of the synthesis and testing of these metal sensitizers that bear functional azolate chelates (both pyrazolate and triazolate), which are capable of modifying the metal sensitizers in a systematic and beneficial manner. Basic principles of the molecular designs, the structural relationship to the photophysical and electrochemical properties, and performances of the as‐fabricated DSSCs are highlighted. The success in the breakthrough of the synthetic protocols and potential applications might provide strong stimulus for the future development of technologies such as DSSCs, organic light‐emitting diodes, solar water splitting, and so forth. Swell cells: The majority of RuII metal‐based dye‐sensitized solar cells (DSSCs) contain at least one thiocyanate ligand. In this review, we report on the preparation of a new family of RuII and OsII sensitizers with various azolate‐containing chelates as the replacement (see figure). Their molecular designs, structural relationship, and performance characteristics are reviewed in light of the future development of organic materials.