Li Li, Zeng Yi, Chen Jinping, Yu Tianjun, Hu Rui, Yang Guoqiang, Li Yi
Key Laboratory of Photochemical Conversion and Optoelectronic Materials , Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190 , China.
University of Chinese Academy of Sciences , Beijing 100049 , China.
J Phys Chem Lett. 2019 Oct 17;10(20):6239-6245. doi: 10.1021/acs.jpclett.9b02393. Epub 2019 Oct 3.
Manipulating triplet states is technically intriguing for organic semiconductors and photochemical conversion. Sensitized photon upconversion that converts low-energy photons into higher-energy ones via triplet fusion holds great potential in augmentation of photovoltaic devices and photocatalysis. Conventional requirement of exothermic triplet-triplet energy transfer in sensitized upconversion constrains the development of upconversion donor-acceptor pairs. We demonstrate an upconversion system by utilizing a triplet energy-deficient donor within a triplet acceptor matrix, in which efficient thermally activated triplet-triplet energy transfer overcoming an energy barrier of up to 180 meV and an over 5% upconversion quantum yield in the solid state are achieved upon 635 nm irradiation at 195 mW/cm. The effective solid-state upconversion through thermally activated triplet-triplet energy transfer establishes a new pathway to extract triplet energy from low-lying sensitizers, transcending traditional restriction in matching components energy level.
对于有机半导体和光化学转换而言，操控三重态在技术上颇具吸引力。通过三重态融合将低能光子转换为高能光子的敏化光子上转换在增强光伏器件和光催化方面具有巨大潜力。敏化上转换中对放热三重态-三重态能量转移的传统要求限制了上转换供体-受体对的发展。我们展示了一种上转换系统，该系统在三重态受体基质中利用三重态能量不足的供体，在195 mW/cm的635 nm照射下，实现了克服高达180 meV能垒的高效热激活三重态-三重态能量转移以及超过5%的固态上转换量子产率。通过热激活三重态-三重态能量转移实现的有效固态上转换建立了一条从低位敏化剂提取三重态能量的新途径，超越了传统的匹配组分能级限制。
