近日，英国剑桥大学的Richard H. Friend&Neil C. Greenham及其研究小组与英国斯旺西大学的Emrys W. Evans等人合作并取得一项新进展。经过不懈努力，他们提出具有自旋双重激子发射的高效近红外有机发光二极管。相关研究成果已于2024年6月19日在国际知名学术期刊《自然—光子学》上发表。

该研究团队提出了一个主客体设计的有机发光二极管，利用能量转移机制，在800nm的发射波长下，成功实现了高达9.6%的外量子效率。三(2,4,6-三氯苯基)甲基-三苯基胺自由基客体在带电荷的蒽衍生物宿主中与三重态能量匹配。研究人员从光谱学和量子化学模型中表明，可逆的主-客体三重态-双重态能量转移允许有效地收集主三重态激子。

据悉，发光有机自由基的发展使材料具有优异的近红外发射光学性能。光产生的应用范围从生物成像到监测。虽然自由基的不成对电子排列使有机发光二极管的双自旋流形内的有效辐射跃迁成为可能，但它们的性能受到电致发光中引入的非辐射路径的限制。

附：英文原文

Title: Efficient near-infrared organic light-emitting diodes with emission from spin doublet excitons

Author: Cho, Hwan-Hee, Gorgon, Sebastian, Londi, Giacomo, Giannini, Samuele, Cho, Changsoon, Ghosh, Pratyush, Tonnel, Claire, Casanova, David, Olivier, Yoann, Baikie, Tomi K., Li, Feng, Beljonne, David, Greenham, Neil C., Friend, Richard H., Evans, Emrys W.

Issue&Volume: 2024-06-19

Abstract: The development of luminescent organic radicals has resulted in materials with excellent optical properties for near-infrared emission. Applications of light generation in this range span from bioimaging to surveillance. Although the unpaired electron arrangements of radicals enable efficient radiative transitions within the doublet-spin manifold in organic light-emitting diodes, their performance is limited by non-radiative pathways introduced in electroluminescence. Here we present a host–guest design for organic light-emitting diodes that exploits energy transfer with up to 9.6% external quantum efficiency for 800nm emission. The tris(2,4,6-trichlorophenyl)methyl-triphenyl-amine radical guest is energy-matched to the triplet state in a charge-transporting anthracene-derivative host. We show from optical spectroscopy and quantum-chemical modelling that reversible host–guest triplet–doublet energy transfer allows efficient harvesting of host triplet excitons.

DOI: 10.1038/s41566-024-01458-3

Source: https://www.nature.com/articles/s41566-024-01458-3