Australian Research Council Centre of Excellence in Exciton Science, School of Chemistry, The University of New South Wales, Sydney, New South Wales, Australia; email:
Annu Rev Phys Chem. 2023 Apr 24;74:145-168. doi: 10.1146/annurev-physchem-092722-104952. Epub 2023 Jan 25.
Photochemical upconversion is a process whereby two lower-energy photons are converted into a higher-energy photon by sensitized triplet-triplet annihilation. While recent interest in this process has been motivated by improving the efficiencies of solar cells, many applications are being explored. In this review, we address the underlying physicochemical phenomena that are responsible for photochemical upconversion. We review their kinetics, and the requirements for annihilators and sensitizers to design efficient upconversion systems. We discuss the spin physics of the bi-excitonic interactions and how the spin character of the triplet pairs can fundamentally limit the upconversion efficiency and give rise to the magnetic field effect on delayed photoluminescence. Finally, we address light-matter coupling phenomena that could be employed to enhance photochemical upconversion.
光化学上转换是一种通过敏化三重态-三重态湮灭将两个低能量光子转换为高能量光子的过程。尽管最近人们对这一过程的兴趣在于提高太阳能电池的效率，但许多应用正在被探索。在这篇综述中，我们讨论了负责光化学上转换的基础物理化学现象。我们回顾了它们的动力学，以及为了设计高效上转换系统对湮灭剂和敏化剂的要求。我们讨论了双激子相互作用的自旋物理，以及三重态对的自旋特性如何从根本上限制上转换效率，并导致磁场对延迟光致发光的影响。最后，我们讨论了可以用来增强光化学上转换的光物质耦合现象。
