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Updated: Mar 26, 2026

Integrating a Triplet-triplet Annihilation Up-conversion System to Enhance Dye-sensitized Solar Cell Response to Sub-bandgap Light
Published on: September 12, 2014
Photon upconversion: from two-photon absorption (TPA) to triplet-triplet annihilation (TTA)
Changqing Ye1, Liwei Zhou1, Xiaomei Wang1
1Jiangsu Key Laboratory for Environmental Functional Materials, Research Center for Green Printing Nanophotonic Materials, Institute of Chemistry, Biology and Materials Engineering, Suzhou University of Science and Technology, Suzhou, 215009, China. wangxiaomei@mail.usts.edu.cn.
Abstract:
Organic upconversion is a unique process in which low-energy light (usually NIR light) is converted to high-energy light through either the two-photon absorption (TPA) mechanism or the triplet-triplet annihilation (TTA) mechanism. Both TPA upconversion (TPA-UC) and TTA upconversion (TTA-UC) have been actively investigated in recent years due to their intriguing applications in optics, biophotonics, and solar energy utilization. Although they show some similarity (i.e., belonging to the nonlinear two-quantum process and needing focused excitation light), TPA-UC and TTA-UC are very different, such as in mechanism, characteristics involved, molecular design and potential applications. Here, we collectively reviewed these two kinds of upconversion processes and compared their respective characteristics and merits. We also present recent advances made in the areas of TPA- and TTA-UC, the remaining challenges and opportunities, with particular emphasis on molecular engineering of these two active upconversion materials.
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