Power-dependent upconversion luminescence intensity in NaYF
 4
 ,Yb
 3+
 ,Er
 3+
 nanoparticles

Li, Ai‐Hua; Lü, Qiang

doi:10.1209/0295-5075/96/18001

Cited by 14 publications

(10 citation statements)

References 34 publications

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“…For red emission, the 4 F 9/2 level must be populated either by further multiphonon relaxations from the 2 H 11/2 and 4 S 3/2 levels or through energy transfer from the ytterbium ion. The high sensitivity of the green 2 H 11/2 and 4 S 3/2 → 4 I 15/2 transitions in the NaYF 4 :Yb,Er system has been used to good effect in temperature sensors. − Because of the close proximity of these energy levels and the dependence of their differences on k B T , where k B is Boltzmann’s constant and T is the absolute temperature (K), the relative peak intensities can be used to predict the lattice temperature of NaYF 4 .…”

Section: Introductionmentioning

confidence: 99%

Iron Oxide-Induced Thermal Effects on Solid-State Upconversion Emissions in NaYF₄:Yb,Er Nanocrystals

Challenor

Gong

Lorenser

et al. 2013

ACS Appl. Mater. Interfaces

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Multifunctional materials exhibiting photon upconversion show promising applications for biological imaging and sensing. In this study, we examine the solid-state upconversion emission of NaYF4:Yb,Er nanoparticles in the presence of iron oxide nanoparticles. Fe3O4 nanoparticles (6 nm) were mixed with NaYF4:Yb,Er nanoparticles (either 10 or 50 nm) in varying proportions by drying chloroform solutions of nanoparticles onto glass slides. Upconversion spectra were acquired, and a laser power-dependent emission was observed and correlated with the iron oxide content in the mixture. Changes in the lattice temperature of the upconverting particles were monitored by careful observation of the relative intensities of the (2)H11/2 and (4)S3/2 →( 4)I15/2 transitions. The emission characteristics observed are consistent with an iron oxide-induced thermal effect that is dependent on both the laser power and the proportion of iron oxide. The results highlight that the thermal effects of mixed nanoparticle systems should be considered in the design of luminescent upconverting hybrid materials.

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Section: Introductionmentioning

confidence: 99%

Iron Oxide-Induced Thermal Effects on Solid-State Upconversion Emissions in NaYF₄:Yb,Er Nanocrystals

Challenor

Gong

Lorenser

et al. 2013

ACS Appl. Mater. Interfaces

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“…And the strength of corresponding nanosized phosphor (<20 nm) is only one of tenth of the bulk 7 8 . Second, because of the presence of the local thermal effect and saturation effect, the UCL intensity will saturate and even quench at relatively high excitation power density, which vitally influences the brightness of UCL 9 . Third, the temperature quenching phenomenon usually happens at high temperature, and the concentration quenching occurs as the concentration of activators is too high 9 10 .…”

mentioning

confidence: 99%

“…Second, because of the presence of the local thermal effect and saturation effect, the UCL intensity will saturate and even quench at relatively high excitation power density, which vitally influences the brightness of UCL 9 . Third, the temperature quenching phenomenon usually happens at high temperature, and the concentration quenching occurs as the concentration of activators is too high 9 10 . In addition, for most of RE activated UCPs based on 4 f -4 f transitions, the excitation band is relatively narrow, which is difficult to satisfy the requirement of various optical devices, especially the requirement of solar spectrum conversion 11 .…”

mentioning

confidence: 99%

Ag-SiO2-Er2O3 Nanocomposites: Highly Effective Upconversion Luminescence at High Power Excitation and High Temperature

Min

et al. 2014

Sci Rep

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Rare Earth (RE) activated upconversion phosphors (UCPs), have demonstrated significant application potentials in some front fields, including solar energy conversion and bio-application. However, some bottleneck problems should be overcame, such as the lower upconversion efficiency, narrower excitation band, concentration-quenching and temperature-quenching. To solve these problems, the Ag-SiO2-Er2O3 nanocomposites were fabricated, in which the upconversion luminescence (UCL) of Er2O3 was white broadband. Through the interaction of Er2O3 with surface plasmon (SP) of silver nanoparticles (SNPs), the threshold power for generating broadbands was suppressed largely in contrast to the Er2O3 nanoparticles (NPs), while the UCL brightness was enhanced remarkably, ranging from several to 104 times, which strongly depended on the power density of excitation light. At excitation power density of 1.50 W/mm2 of 980 nm light, the UCL intensity of Ag-SiO2-Er2O3 is 40-folds than the well-known NaYF4:Yb3+,Er3+ commercial powders. And more, it is also interesting to observe that the composites demonstrate two excitation bands extending of 780–980 nm, highly improved UCL with elevated temperature and excitation power density. The UCL mechanism related to UCL enhancement was carefully studied.

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“…The emission bands centered at 521 nm (G1) and 539 nm (G2) can be referred to as the 2 H 11/2 → 4 I 15/2 and 4 S 3/2 → 4 I 15/2 transitions (sum of both: G full ), respectively . The emission band centered at 653 nm (R) is assigned to the 4 F 9/2 → 4 I 15/2 transition of the Er 3+ ion. ,,− The influence of Gd 3+ on the spectral intensity distribution was different for the Y 3+ lattice versus Sc 3+ lattice. While for the Y 3+ lattice, only a small effect upon increasing the Gd 3+ content on the spectral intensity distribution was observed (strongest for the G2 band, but none for G1 and R bands); for the Sc 3+ -based UCNPs, all bands (G1, G2, R) showed a distinct alteration due to the increase in Gd 3+ content.…”

Section: Resultsmentioning

confidence: 99%

“…In eq , n is the number of NIR photons absorbed per visible photon emitted. ,− ,− The value of n at relatively low pump powers is approximately equal to the number of pump photons involved in the excitation process. , If the pump power is very high, a saturation of UCL intensity may be observed. ,,, Figure a shows the UCL intensities of NaSc:7.5 in dependence of power density for pulsed excitation, and Figure b shows the slope of log( I ) versus log( P ) for green and red emission intensities. The logarithmic intensities of all transitions for all samples show linearity, as expected at a low power density range (1.6–14.2 W/cm 2 ); hence, no saturation effects were observed. , Furthermore, the population of green-emitting and red-emitting energy levels exhibits a quasi-quadratic relationship with pump power at low Er 3+ and Yb 3+ concentrations .…”

Section: Resultsmentioning

confidence: 99%

Looking at Sc(III) and Y(III) Lattices for Upconversion Nanoparticles Complemented by Eu(III) Down-Shifting Luminescence

Nacak,

Kumke

2023

J. Phys. Chem. C

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Upconversion nanoparticles (UCNPs) are valuable materials mostly used in medicine, anticounterfeiting, optical imaging, and solar cells. NaYF 4 is mostly used as a host lattice for lanthanides. As an alternative, Na x ScF 3+x is worth investigating because it can also provide a host lattice with low phonon energy. The crystal structure and subsequently the phonon energy can be altered when Gd 3+ is introduced into the host lattice, which has been frequently shown for NaYF 4 . Subsequently, the upconversion luminescence properties change. Here, NaYF 4 :Yb 3+ :Er 3+ and Na x ScF 3+x :Yb 3+ :Er 3+ upconversion nanoparticles with various amounts of Gd 3+ were synthesized using a standard thermal decomposition approach, which has not been optimized for the specific composition of the UCNP. In addition, the UCNPs were doped with Eu 3+ as an optical probe to be used in downshifting luminescence measurements. Time-resolved and power-dependent as well as temperature-dependent upconversion luminescence measurements were carried out to collect a standard parameter set for each UCNP. The data showed that Gd 3+ addition differently altered the upconversion luminescence properties in both lattices. Distinct changes were especially observed for the samples with the Na x ScF 3+x lattice. Upconversion luminescence lifetimes of Er 3+ increased for Na x ScF 3+x samples upon adding Gd 3+ , while they decreased for samples based on NaYF 4 . Temperature-dependent measurements revealed that the samples of the NaYF 4 host lattice showed a slightly larger variation in S R and ΔE values with a change in the Gd 3+ content. On the other hand, for the Na x ScF 3+x lattice, Gd 3+ addition had only a minor influence on these parameters. The number of IR photons required for the generation of an upconversion luminescence photon was determined as 2 for the red emission (indicating a reduced back energy transfer) and green emission of Er 3+ in both lattices. Due to the unique optical properties of Eu 3+, complementary information on minute changes occurring in the two host crystal lattices upon Gd 3+ addition was obtained. The samples have been doped with 0.5 mol % Eu 3+ , and a detailed analysis of the Eu 3+ luminescence (at room temperature as well as under site-selective excitation conditions at T = ∼4K) was carried out to track the changes in the crystal structure of the host materials using the method parallel factor analysis (PARAFAC) to process spectral as well as kinetic data. Two Eu 3+ species for samples in the NaYF 4 host lattice and three Eu 3+ species for samples in the Na x ScF 3+x lattice were found based on PARAFAC analysis.

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Power-dependent upconversion luminescence intensity in NaYF ₄ ,Yb ³⁺ ,Er ³⁺ nanoparticles

Cited by 14 publications

References 34 publications

Iron Oxide-Induced Thermal Effects on Solid-State Upconversion Emissions in NaYF₄:Yb,Er Nanocrystals

Iron Oxide-Induced Thermal Effects on Solid-State Upconversion Emissions in NaYF₄:Yb,Er Nanocrystals

Ag-SiO2-Er2O3 Nanocomposites: Highly Effective Upconversion Luminescence at High Power Excitation and High Temperature

Looking at Sc(III) and Y(III) Lattices for Upconversion Nanoparticles Complemented by Eu(III) Down-Shifting Luminescence

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Power-dependent upconversion luminescence intensity in NaYF 4 ,Yb 3+ ,Er 3+ nanoparticles

Cited by 14 publications

References 34 publications

Iron Oxide-Induced Thermal Effects on Solid-State Upconversion Emissions in NaYF4:Yb,Er Nanocrystals

Iron Oxide-Induced Thermal Effects on Solid-State Upconversion Emissions in NaYF4:Yb,Er Nanocrystals

Ag-SiO2-Er2O3 Nanocomposites: Highly Effective Upconversion Luminescence at High Power Excitation and High Temperature

Looking at Sc(III) and Y(III) Lattices for Upconversion Nanoparticles Complemented by Eu(III) Down-Shifting Luminescence

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Product

Resources

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Power-dependent upconversion luminescence intensity in NaYF ₄ ,Yb ³⁺ ,Er ³⁺ nanoparticles

Iron Oxide-Induced Thermal Effects on Solid-State Upconversion Emissions in NaYF₄:Yb,Er Nanocrystals

Iron Oxide-Induced Thermal Effects on Solid-State Upconversion Emissions in NaYF₄:Yb,Er Nanocrystals