Size/morphology induced tunable luminescence in upconversion crystals: ultra-strong single-band emission and underlying mechanisms

Wang, Zhaofeng; Zeng, Songshan; Yu, Jingfang; Ji, Xiaoli; Zeng, Huidan; Xin, Shuangyu; Wang, Yuhua; Sun, Luyi

doi:10.1039/c5nr01008j

Cited by 15 publications

(5 citation statements)

References 34 publications

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“…The UCL intensity depending on the power of the near-infrared (NIR) laser in Figure S5 demonstrates that the UCL of Er 3+ and Tm 3+ in LiNbO 3 could be attributed to the two-photon and three-photon processes, respectively. 24,25 The UCL of Tm 3+ doped in LiNbO 3 can only be observed after codoping Yb 3+ , suggesting that the UCL mechanism of Tm 3+ is associated with the energy transfer process from Yb 3+ to Tm 3+ . 24 The corresponding UCL mechanisms of LiNbO 3 :Er 3+ and LiNbO 3 :Tm 3+ , Yb 3+ are illustrated in Figure S6.…”

Section: Resultsmentioning

confidence: 99%

Multilevel Static–Dynamic Anticounterfeiting Based on Stimuli-Responsive Luminescence in a Niobate Structure

Sang

Zhou

Zhang

et al. 2019

ACS Appl. Mater. Interfaces

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Anticounterfeiting is a highly required technique to protect the product and the consumer rights in the modern society. The conventional luminescent anticounterfeiting is based on downconversion luminescence excited by an ultraviolet light, which is easy to be faked. In this work, we realized six luminescent modes in a niobate-based structure (LiNbO3:RE3+, RE3+ = Pr3+, Tm3+, Er3+, Yb3+), in which photostimulated luminescence of LiNbO3:Pr3+, and upconversion luminescence color evolution of LiNbO3:Er3+ were first presented. Based on the above luminescent modes of LiNbO3:RE3+, multilevel anticounterfeiting devices were developed. By employing mechanoluminescence and persistent luminescence, we achieved dual-mode anticounterfeiting that could display the luminescent patterns without any direct irradiation. In addition, another dual-mode anticounterfeiting based on photostimulated luminescence and upconversion luminescence excited by a near-infrared light was realized, which could display the anticounterfeiting patterns in both static and dynamic states. To obtain an even higher anticounterfeiting level, downconversion luminescence, thermoluminescence, photostimulated luminescence, and upconversion luminescence were simultaneously applied in a food trademark. This four-mode anticounterfeiting trademark could not only show a static–dynamic luminescence that is hard to be faked but also allow consumers to distinguish the food freshness. The presented multilevel anticounterfeiting strategies could be employed to resolve the counterfeit issues in various fields.

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Section: Resultsmentioning

confidence: 99%

Multilevel Static–Dynamic Anticounterfeiting Based on Stimuli-Responsive Luminescence in a Niobate Structure

Sang

Zhou

Zhang

et al. 2019

ACS Appl. Mater. Interfaces

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“…In general, optical absorption spectra depend on the shape, size, strain and vacancies present in the sample. Wang et al [35] observed blue shift for nanoparticles and nanorod, which is due to quantum confinement effect. Calculation of optical energy gap of compounds from the absorbance spectra using Woods and Tauc's function [36] is given as where α is the linear absorption co-efficient of the materials, hν is the energy of the photon, 'A' is proportionality constant of characteristic material, and n equals either ½ for indirect transition or 2 for direct transitions (Fig.…”

Section: Uv-vis-nir Spectra Studiesmentioning

confidence: 97%

Optical and magnetic properties of pure and Er, Yb-doped β-NaYF4 hexagonal plates for biomedical applications

Namagal

Jaya

Muralidharan

et al. 2020

J Mater Sci: Mater Electron

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The effects of Yb, Er on structural, optical, magnetic and biocompatibility of β-NaYF 4 compounds were examined. The pure and Yb, Er-doped β-NaYF 4 compounds were synthesized via simple hydrothermal method. X-ray diffraction analysis revealed the hexagonal crystal structure. The functional group present in the sample was identified by FT-IR analysis. The vibrational bands were analysed by Raman spectroscopy. Electron Microscope images exhibit the hexagonal plate-like morphology. The characteristic absorbance peaks of Yb, Er and host were obtained in UV-VIS-NIR absorbance spectra. The interesting green and enhanced red emission through Photoluminescence spectra of the prepared compounds might be useful for bio-imaging. Pure β-NaYF 4 possessed diamagnetic property and Yb, Er-doped β-NaYF 4 exhibited paramagnetic property at room temperature. Yb, Er-doped β-NaYF 4 was incubated with HeLa cells and assessed cytotoxicity using MTT assay. Hence, Yb, Er-doped β-NaYF 4 materials have promising application in cell imaging and bio-separation applications.

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“…This effect underpins the well-documented size dependence of the observed UC luminescence lifetimes 46 . There is limited literature on specific effect of defects in nanoparticles due to characterization challenges 86,87 . We were first to analyze the X-ray diffraction data in UCNPs to obtain information on defect densities 46 .The XRD peak position is sensitive to the variation of the lattice constant due to defect induced strain, which provides a measure of the overall defect density.…”

Section: Nonradiative Relaxationmentioning

confidence: 99%

Lanthanide upconversion luminescence at the nanoscale: fundamentals and optical properties

2016

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Upconversion photoluminescence is a nonlinear effect where multiple lower energy excitation photons produce higher energy emission photons. This fundamentally interesting process has many applications in biomedical imaging, light source and display technology, and solar energy harvesting. In this review we discuss the underlying physical principles and their modelling using rate equations. We discuss how the understanding of photophysical processes enabled strategic influence over the optical properties of upconversion especially in rationally designed materials. We subsequently present an overview of recent experimental strategies to control and optimize the optical properties of upconversion nanoparticles, focussing on their emission spectral properties and brightness. TOC

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Size/morphology induced tunable luminescence in upconversion crystals: ultra-strong single-band emission and underlying mechanisms

Cited by 15 publications

References 34 publications

Multilevel Static–Dynamic Anticounterfeiting Based on Stimuli-Responsive Luminescence in a Niobate Structure

Multilevel Static–Dynamic Anticounterfeiting Based on Stimuli-Responsive Luminescence in a Niobate Structure

Optical and magnetic properties of pure and Er, Yb-doped β-NaYF4 hexagonal plates for biomedical applications

Lanthanide upconversion luminescence at the nanoscale: fundamentals and optical properties

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