Visible and ultraviolet upconversion and near infrared downconversion luminescence from lanthanide doped La2Zr2O7 nanoparticles

Gupta, Santosh K.; Garcia, Mitzy A. Penilla; Zuniga, Jose P.; Abdou, Maya; Mao, Yuanbing

doi:10.1016/j.jlumin.2019.116591

Cited by 33 publications

(28 citation statements)

References 64 publications

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“…Sharp and intense diffraction profiles were indexed to a cubic pyrochlore type structure and well-matched with JCPDS No. :78-1292 61 . No additional impurity/dopant peaks were identified indicating that dopant Tb 3+ ions were effectively substituted in the LZO sites.…”

Section: Resultsmentioning

confidence: 99%

One material, many possibilities via enrichment of luminescence in La2Zr2O7:Tb3+ nanophosphors for forensic stimuli aided applications

Lavanya

Darshan

Malleshappa

et al. 2022

Sci Rep

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Engineering a single material with multidirectional applications is crucial for improving productivity, low cost, flexibility, least power consumption, etc. To achieve these requirements, novel design structures and high-performance materials are in urgent need. Lanthanide-doped nanophosphors have the greatest strengths and ability in order to tune their applications in various dimensions. However, applications of nanophosphor in latent fingerprints visualization, anti-counterfeiting, and luminescent gels/films are still in their infancy. This study demonstrated a simple strategy to enhance the luminescence of Tb3+ (1–11 mol %) doped La2Zr2O7 nanophosphors by conjugating various fluxes via a simple solution combustion route. The photoluminescence emission spectra reveal intense peaks at ~ 491, 546, 587, and 622 nm, which arises from 5D4 → 7FJ (J = 6, 5, 4, 3) transitions of Tb3+ ions, respectively. The highest emission intensity was achieved in the NH4Cl flux assisted nanophosphor as compared to NaBr and NH4F assisted samples. The colorimetric images of fingerprints visualized using the optimized nanophosphor on forensic related surfaces exhibit level –III ridge details, including sweat pores, the width of the ridges, bifurcation angle, and the successive distance between sweat pores, etc. These results are decisive parameters that clearly support the statement “no two persons have ever been found to have the same fingerprints”. The anti-counterfeiting security ink was formulated using optimized nanophosphor and various patterns were designed by simple screen printing and dip pen technologies. The encoded information was decrypted only under ultraviolet 254 nm light. All the designed patterns are exhibit not just what it looks/feel like and how better it works. As a synergetic contribution of enhanced luminescence of the prepared nanophosphor, the green-emissive films were fabricated, which display excellent flexibility, uniformity, and transparency in the normal and ultraviolet 254 nm light illumination. The aforementioned results revealed that the prepared NH4Cl flux-assisted La2Zr2O7: Tb3+(7 mol %) NPs are considered to be the best candidate for multi-dimensional applications.

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Section: Resultsmentioning

confidence: 99%

One material, many possibilities via enrichment of luminescence in La2Zr2O7:Tb3+ nanophosphors for forensic stimuli aided applications

Lavanya

Darshan

Malleshappa

et al. 2022

Sci Rep

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“…We also calculated the phonon frequencies using and the phonon dispersion along the high-symmetry K-path of the Brillouin zone of both LF and LOF using the DFT and PBE methods, respectively . The phonon dispersion plots (Supporting Information S7, Figure c,d) calculated using the PBE method showed a greater number of imaginary modes for LF than LOF.…”

Section: Theoretical Calculationsmentioning

confidence: 99%

“…Along with UV and visible UC emissions, Er 3+ shows multiple DC emissions in the NIR and MIR ranges, namely, 4 I 13/2 → 4 I 15/2 and 4 I 11/2 → 4 I 13/2 transitions. In terms of UC luminescence, Er 3+ offers multiple radiative energy-level transitions in the visible range, including yellow-green 2 H 11/2 , 4 S 3/2 → 4 I 15/2 , and red 4 F 9/2 → 4 I 15/2 transitions. , However, the forbidden nature of the Er 3+ f–f transitions gives a low absorption coefficient, resulting in low UC and DC efficiencies . Ytterbium (Yb), by contrast, has only a single energy transition of 2 F 7/2 → 2 F 5/2 , which corresponds to 980 nm .…”

Section: Introductionmentioning

confidence: 99%

Up- and Down-Convertible LaF₃:Yb,Er Nanocrystals with a Broad Emission Window from 350 nm to 2.8 μm: Implications for Lighting Applications

Pokhrel

Gupta

Perez

et al. 2021

ACS Appl. Nano Mater.

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In this study, emissions between 350 nm and 2.8 μm are produced from molten-salt-synthesized LaF3:Yb3+,Er3+ (LFYE) nanocrystals (NCs) under 980 nm excitation. In fact, such wide spectral emissions from a single phosphor would be highly favorable in lighting applications ranging from light-emitting diodes, optical fibers, and telecommunications. Upconversion luminescence (UCL) spectra show intense red emission compared to the green band below 6 mW, wherein a strong green emission is achieved compared to a red emission when the laser power is increased beyond 85 mW. To further enhance their UCL and downconversion luminescence (DCL), the LFYE NCs are annealed at 400 °C for 30, 60, 90, and 120 min. Their UCL and DCL intensities are improved with up to 90 min of annealing but drastically reduced after annealing for 120 min. The latter is caused by both phase transition and shape changes, that is, from the cubic LFYE NCs to tetragonal LaOF:Yb3+,Er3+ (LOFYE) NCs with a square pyramidal shape. Density functional theory calculations show that the LOFYE NCs are more thermodynamically favorable to form due to their lower defect formation energy than the LFYE NCs. Moreover, LaF3 is dynamically more unstable in comparison to LaOF, as indicated by a greater number of imaginary modes for LaF3 in the phonon dispersion plot. Interestingly, the highest phonon energy for LaF3 is found to be 439 cm–1 while that of LaOF is 527 cm–1, which is expected to play a role in the different emission behaviors between LaF3 and LaOF. Our work shows exemplary potential of the LFYE NCs with near-ultraviolet to mid-infrared emissions as UCL and DCL for laser power-induced color tunability for a wide range of applications.

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“…3 Among various light-emitting materials, upconversion (UC) nanoparticles (NPs), which convert low energy photons into high energy photons, have been attracting increasing attention in the scientific community because of their applications in various areas of science and technology. 4 UCNPs have been exploited in several applications, which are directly associated with daily life such as optoelectronic devices, 5 anticounterfeiting, 6 photodynamic therapy, 7 bioimaging, 3 renewable energy, 8 and thermochromic phosphors for switching devices. 9 The design of high quality and efficient UCNPs requires judicious choice of host lattices and dopant ions.…”

Section: Introductionmentioning

confidence: 99%

Single red emission from upconverting ZnGa₂O₄:Yb,Er nanoparticles co-doped by Cr³⁺

2020

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Visible and ultraviolet upconversion and near infrared downconversion luminescence from lanthanide doped La2Zr2O7 nanoparticles

Cited by 33 publications

References 64 publications

One material, many possibilities via enrichment of luminescence in La2Zr2O7:Tb3+ nanophosphors for forensic stimuli aided applications

One material, many possibilities via enrichment of luminescence in La2Zr2O7:Tb3+ nanophosphors for forensic stimuli aided applications

Up- and Down-Convertible LaF₃:Yb,Er Nanocrystals with a Broad Emission Window from 350 nm to 2.8 μm: Implications for Lighting Applications

Single red emission from upconverting ZnGa₂O₄:Yb,Er nanoparticles co-doped by Cr³⁺

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Visible and ultraviolet upconversion and near infrared downconversion luminescence from lanthanide doped La2Zr2O7 nanoparticles

Cited by 33 publications

References 64 publications

One material, many possibilities via enrichment of luminescence in La2Zr2O7:Tb3+ nanophosphors for forensic stimuli aided applications

One material, many possibilities via enrichment of luminescence in La2Zr2O7:Tb3+ nanophosphors for forensic stimuli aided applications

Up- and Down-Convertible LaF3:Yb,Er Nanocrystals with a Broad Emission Window from 350 nm to 2.8 μm: Implications for Lighting Applications

Single red emission from upconverting ZnGa2O4:Yb,Er nanoparticles co-doped by Cr3+

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Up- and Down-Convertible LaF₃:Yb,Er Nanocrystals with a Broad Emission Window from 350 nm to 2.8 μm: Implications for Lighting Applications

Single red emission from upconverting ZnGa₂O₄:Yb,Er nanoparticles co-doped by Cr³⁺