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High Quantum Yield Single‐Band Green Upconversion in La 2 O 3 :Yb 3+ , Ho 3+ Microcrystals for Anticounterfeiting and Plastic Recycling
Author(s) -
Gao Guojun,
Busko Dmitry,
Joseph Reetu,
Turshatov Andrey,
Howard Ian A.,
Richards Bryce S.
Publication year - 2019
Publication title -
particle and particle systems characterization
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.877
H-Index - 56
eISSN - 1521-4117
pISSN - 0934-0866
DOI - 10.1002/ppsc.201800462
Subject(s) - photon upconversion , quantum yield , yield (engineering) , materials science , nanotechnology , optoelectronics , analytical chemistry (journal) , chemistry , optics , physics , metallurgy , doping , fluorescence , chromatography
Single‐band green upconversion (UC) with high green purity and color stability is urgently required for plastic recycling and anticounterfeiting. However, it is very difficult to obtain single‐band green emission for benchmark Yb 3+ /Er 3+ activated UC materials (such as NaYF 4 :Yb 3+ ,Er 3+ ) due to the strong accompanying red UC. Herein, highly efficient and stable single‐band green UC is reported in La 2 O 3 :Yb 3+ /Ho 3+ (LYH) microcrystals with record high absolute UC quantum yield (UCQY) of 2.6% for single‐band green UC. LYH yields pure green UC with large and stable intensity ratio, I Green / I Red ≈ 18. LYH presents not only higher UCQY for a single‐band green UC but also much more pure and stable green UC than the benchmark UC materials such as NaYF 4 :Yb 3+ ,Er 3+ and Gd 2 O 2 S:Yb 3+ ,Er 3+ . These results suggest that the newly developed LYH can, in principle, be promising for anticounterfeiting and plastic recycling. Its proof‐of‐concept is demonstrated as a security label based on a transparent institute logo.