Multicolor Tunable Upconversion Luminescence from Sensitized Seed-Mediated Grown LiGdF<sub>4</sub>:Yb,Tm-Based Core/Triple-Shell Nanophosphors for Transparent Displays

Shin, Jungcheol; Kyhm, Jihoon; Hong, A-Ra; Song, Jin Dong; Lee, Kwangyeol; Ko, Hyungduk; Jang, Ho Seong

doi:10.1021/acs.chemmater.8b02497

Cited by 72 publications

(47 citation statements)

References 51 publications

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“…Moreover, the lattice mismatch between an undoped LiYF4 shell and the doped LiYF4 core particle is low which reduces the risk of forming defect states at the core-shell interface. Other shell materials were nevertheless also investigated such as LiGdF4 [65,69], LiLuF4 [71], LiYbF4 [73], SiO2 [63,80], doped LiYF4 [76,77] as well as more complicated particle architectures involving multiple shells [69,74].…”

Section: Introductionmentioning

confidence: 99%

LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with luminescence decay times similar to YLF laser crystals and the upconversion quantum yield of the Yb,Er doped nanocrystals

et al. 2020

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We developed a procedure to prepare luminescent LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with a size of approximately 40 nm revealing luminescence decay times of the dopant ions that approach those of high-quality laser crystals of LiYF4:Yb (Yb:YLF) and LiYF4:Yb,Er (Yb,Er:YLF) with identical doping concentrations. As the luminescence decay times of Yb3+ and Er3+ are known to be very sensitive to the presence of quenchers, the long decay times of the core/shell nanocrystals indicate a very low number of defects in the core particles and at the core/shell interfaces. This improvement in the performance was achieved by introducing two important modifications in the commonly used oleic acid based synthesis. First, the shell was prepared via a newly developed method characterized by a very low nucleation rate for particles of pure LiYF4 shell material. Second, anhydrous acetates were used as precursors and additional drying steps were applied to reduce the incorporation of OH− in the crystal lattice, known to quench the emission of Yb3+ ions. Excitation power density (P)-dependent absolute measurements of the upconversion luminescence quantum yield (ΦUC) of LiYF4:Yb,Er/LiYF4 core/shell particles reveal a maximum value of 1.25% at P of 180 Wcm−2. Although lower than the values reported for NaYF4:18%Yb,2%Er core/shell nanocrystals with comparable sizes, these ΦUC values are the highest reported so far for LiYF4:18%Yb,2%Er/LiYF4 nanocrystals without additional dopants. Further improvements may nevertheless be possible by optimizing the dopant concentrations in the LiYF4 nanocrystals.

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Section: Introductionmentioning

confidence: 99%

LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with luminescence decay times similar to YLF laser crystals and the upconversion quantum yield of the Yb,Er doped nanocrystals

et al. 2020

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“…Subsequently, fluoride anions engage in fluorination and cleave Gd-OOCCF 3 bonds to promote nucleation, and the thus obtained crystal nuclei agglomerate to form larger particles as the reaction progresses. With the increase of temperature, the growth rate of these nuclei crystal nucleus increases and eventually forms nanocrystals [45][46][47][48].…”

Section: Resultsmentioning

confidence: 99%

Facile Synthesis of Yb³⁺- and Er³⁺-Codoped LiGdF₄ Colloidal Nanocrystals with High-Quality Upconversion Luminescence

Zhang

2019

Journal of Nanomaterials

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Herein, we synthesized high-quality colloidal nanocrystals of Yb3+/Er3+-codoped LiGdF4 with intense green emission by using a facile route and turning the associated reaction parameters. Moreover, we probed the effects of reaction conditions on nanocrystal properties (crystal structure, morphology, and luminescence) and gained valuable mechanistic insights into nucleation and growth processes. Sample purity was found to depend on LiOH·H2O concentration, reaction temperature, and time, which allowed us to manipulate sample purity and thus obtain species ranging from mixtures of LiGdF4:Yb3+/Er3+ with GdF3 to pure tetragonal-phase LiGdF4:Yb3+/Er3+. Investigation of upconversion luminescence properties and the luminescence lifetime of as-prepared samples revealed that LiGdF4 is a promising host material for realizing the desired upconversion luminescence.

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“…It is worth noting that the gadolinium network‐mediated energy migration strategy to tune the UC characteristics of CSX structures relies on a five‐photon process whose efficiency as a function of the excitation power density has rarely been reported through the measurement of the corresponding absolute UCQY. As far as it is known, only recently Shin et al have reported the absolute UCQY for LiYF 4 :Yb/LiGdF 4 :Yb:Tm/LiGdF 4 :Tb:Eu/LiYF 4 (tetragonal phase) ranging from 1.1% to 2.5% at 106 W cm −2 …”

Section: Core–shell Upconverting Architecturesmentioning

confidence: 99%

Structure–Property Relationships in Lanthanide‐Doped Upconverting Nanocrystals: Recent Advances in Understanding Core–Shell Structures

et al. 2019

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The production of upconverting nanostructures with tailored optical properties is of major technological interest, and rapid progress toward the realization of such production has been made in recent years. Ultimately, accurate understanding of nanostructure organization will lead to design rules for accurately tailoring optical properties. Here, the context of open questions still of general importance to the upconversion and nanocrystal communities is presented, with a particular emphasis on the structure–property relationships of core–shell upconverting nanocrystals. Although the optical properties of the latter have been thoroughly investigated, little is known regarding their atomic‐scale organization. Indeed, solving the atomic‐scale structure of such nanomaterials is challenging because of their intrinsic nonperiodic nature. Familiar concepts of crystallography are no longer appropriate; chemical and structural modulation waves must be introduced. To reveal the exact core–shell structures, innovative characterization techniques need to be applied and developed, as discussed herein. The continued development and application of structural characterization techniques will be vital to consolidate the currently incomplete link between atomic‐scale structure and upconversion properties. This will ultimately provide a valuable contribution to the emerging detailed guidelines on how to better design upconverting nanostructures to achieve given optical properties in terms of efficiency, absorption, spectral emission, and dynamics.

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Multicolor Tunable Upconversion Luminescence from Sensitized Seed-Mediated Grown LiGdF₄:Yb,Tm-Based Core/Triple-Shell Nanophosphors for Transparent Displays

Cited by 72 publications

References 51 publications

LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with luminescence decay times similar to YLF laser crystals and the upconversion quantum yield of the Yb,Er doped nanocrystals

LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with luminescence decay times similar to YLF laser crystals and the upconversion quantum yield of the Yb,Er doped nanocrystals

Facile Synthesis of Yb³⁺- and Er³⁺-Codoped LiGdF₄ Colloidal Nanocrystals with High-Quality Upconversion Luminescence

Structure–Property Relationships in Lanthanide‐Doped Upconverting Nanocrystals: Recent Advances in Understanding Core–Shell Structures

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Multicolor Tunable Upconversion Luminescence from Sensitized Seed-Mediated Grown LiGdF4:Yb,Tm-Based Core/Triple-Shell Nanophosphors for Transparent Displays

Cited by 72 publications

References 51 publications

LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with luminescence decay times similar to YLF laser crystals and the upconversion quantum yield of the Yb,Er doped nanocrystals

LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with luminescence decay times similar to YLF laser crystals and the upconversion quantum yield of the Yb,Er doped nanocrystals

Facile Synthesis of Yb3+- and Er3+-Codoped LiGdF4 Colloidal Nanocrystals with High-Quality Upconversion Luminescence

Structure–Property Relationships in Lanthanide‐Doped Upconverting Nanocrystals: Recent Advances in Understanding Core–Shell Structures

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Multicolor Tunable Upconversion Luminescence from Sensitized Seed-Mediated Grown LiGdF₄:Yb,Tm-Based Core/Triple-Shell Nanophosphors for Transparent Displays

Facile Synthesis of Yb³⁺- and Er³⁺-Codoped LiGdF₄ Colloidal Nanocrystals with High-Quality Upconversion Luminescence