Li Y, Jiang L, Liu W, Xu S, Li TY, Fries F, Zeika O, Zou Y, Ramanan C, Lenk S, Scholz R, Andrienko D, Feng X, Leo K, Reineke S (2021)
Publication Type: Journal article
Publication year: 2021
Book Volume: 33
Article Number: 2101844
Journal Issue: 39
Persistent luminescence from triplet excitons in organic molecules is rare, as fast non-radiative deactivation typically dominates over radiative transitions. This work demonstrates that the substitution of a hydrogen atom in a derivative of phenanthroimidazole with an N-phenyl ring can substantially stabilize the excited state. This stabilization converts an organic material without phosphorescence emission into a molecular system exhibiting efficient and ultralong afterglow phosphorescence at room temperature. Results from systematic photophysical investigations, kinetic modeling, excited-state dynamic modeling, and single-crystal structure analysis identify that the long-lived triplets originate from a reduction of intrinsic non-radiative molecular relaxations. Further modification of the N-phenyl ring with halogen atoms affects the afterglow lifetime and quantum yield. As a proof-of-concept, an anticounterfeiting device is demonstrated with a time-dependent Morse code feature for data encryption based on these emitters. A fundamental design principle is outlined to achieve long-lived and emissive triplet states by suppressing intrinsic non-radiative relaxations in the form of molecular vibrations or rotations.
APA:
Li, Y., Jiang, L., Liu, W., Xu, S., Li, T.-Y., Fries, F.,... Reineke, S. (2021). Reduced Intrinsic Non-Radiative Losses Allow Room-Temperature Triplet Emission from Purely Organic Emitters. Advanced Materials, 33(39). https://doi.org/10.1002/adma.202101844
MLA:
Li, Yungui, et al. "Reduced Intrinsic Non-Radiative Losses Allow Room-Temperature Triplet Emission from Purely Organic Emitters." Advanced Materials 33.39 (2021).
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