More concerns to iridium complexes are recently put on light-harvesting applications due to its fast spin-orbital coupling and long triplet lifetimes. The strategies and rules on how to tune the emission energy and improve emission efficiency of the iridium complexes are well established after active investigations in the past two decades. However, the knowledge on how to extend the absorption response of the iridium complexes toward lower energy of the visible region, and improve quantum yields and lifetimes of the excited triplet state by rational molecular design are still deficiency for scientists. Meanwhile, these parameters are crucial important for iridium complexes to be efficient photosensitizer. In this review, the general photophysical process of the iridium complex, the developed strategies/rules for tuning the absorption properties,triplet lifetimes and quantum yield of the iridium complexes are discussed. The relationships between the molecular structure of the iridium complexes and their photophyscial characteristics related to photosensitization behavior are elucidated. Also the recent development of the dye-sensitized solar cells, triplet-triplet annihilation energy upconversion, and photoinduced hydrogen production using iridium complexes as photosensitizer are reviewed.
Contents
1 Introduction
2 The photophysical characteristics of the iridium complexes and their regulation
2.1 The photophysics of the iridium complexes
2.2 The basic rules for improving absorption capacity of the iridium complexes in visible-light region
2.3 The management of triplet lifetime of the iridium complex
3 Applications of the iridium complex
3.1 Dye-sensitized solar cells
3.2 Triplet-triplet annihilation energy upconversion
3.3 Photoinduced hydrogen production
4 Conclusion