Upconversion Dynamics in Er3+‐Doped Gd2O2S: Influence of Excitation Power, Er3+ Concentration, and Defects

Martín-Rodríguez, Rosa; Rabouw, Freddy T.; Trevisani, Mattia; Bettinelli, Marco; Meijerink, Andries

doi:10.1002/adom.201400588

Cited by 70 publications

(54 citation statements)

References 29 publications

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“…As other work reported before, the rising edge is proved to be another evidence of CR as theoretical transients [39, 41]. Combined with the luminescence spectra, CR process of 4 F 3/2 + 4 I 15/2 → 4 F 9/2 + 4 I 13/2 makes large contribution to the population of the 4 F 9/2 state due to the higher and higher concentration of Er 3+ in the shell, which also can be obtained from the calculated results of the lifetimes (Fig.…”

Section: Resultssupporting

confidence: 72%

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Enhance the Er3+ Upconversion Luminescence by Constructing NaGdF4:Er3+@NaGdF4:Er3+ Active-Core/Active-Shell Nanocrystals

Wang

Meng

et al. 2017

Nanoscale Res Lett

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NaGdF4:12%Er3+@NaGdF4:x%Er3+ (x = 0, 6, 8, 10, and 12) active-core/active-shell nanoparticles (NPs) were peculiarly synthesized via a delayed nucleation pathway with procedures. The phase, shape, and size of the resulting core–shell NPs are confirmed by transmission electron microscopy and X-ray diffraction. Coated with a NaGdF4:10%Er3+ active shell around the NaGdF4:12%Er3+ core NPs, a maximum luminescent enhancement of about 336 times higher than the NaGdF4:12%Er3+ core-only NPs was observed under the 1540 nm excitation. The intensity ratio of green to red was adjusted through the construction of the core–shell structure and the change of Er3+ concentration in the shell. By analyzing the lifetimes of emission bands and exploring the energy transition mechanism, the giant luminescence enhancement is mainly attributed to the significant increase in the near-infrared absorption at 1540 nm and efficient energy migration from the shell to core.

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Section: Resultssupporting

confidence: 72%

“…6, the profile of NaGdF 4 :12%Er 3+ @NaGdF 4 :10%Er 3+ NPs at 660 nm presents a typical slow rising edge. This phenomenon is a direct evidence of an energy transfer upconversion process of state 4 F 9/2 [39]. As depicted in Fig.…”

Section: Resultsmentioning

confidence: 92%

Enhance the Er3+ Upconversion Luminescence by Constructing NaGdF4:Er3+@NaGdF4:Er3+ Active-Core/Active-Shell Nanocrystals

Wang

Meng

et al. 2017

Nanoscale Res Lett

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“…As can be seen, the UC emission intensity from Yb 3+ increases first and then decreases with an increase in Yb 3+ concentration. Considering the efficient ET process from Yb 3+ to Er 3+ , Er 3+ → Yb 3+ → Er 3+ ETU process should be an important mechanism for the UC luminescence of Er 3+ when excited at 1550 nm 11,33,34 . Therefore, the UC luminescence mechanism of Er 3+ can be described by the following processes.…”

Section: Resultsmentioning

confidence: 99%

Up-conversion luminescence, temperature sensing properties and laser-induced heating effect of Er3+/Yb3+ co-doped YNbO4 phosphors under 1550 nm excitation

Wang

Zhong

et al. 2018

Sci Rep

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YNbO4 phosphors with various Er3+ and Yb3+ concentrations were synthesized via a traditional high-temperature solid-state reaction method. Their crystal structure was investigated by means of X-ray diffraction (XRD) and Rietveld refinements, and it was confirmed that the obtained samples exist in monoclinic phase. The Er3+ and Yb3+ concentration-dependent up-conversion (UC) luminescence was studied under 1550 nm excitation. By inspecting the dependence of UC intensity on the laser working current, it was found that four-photon and three-photon population processes were co-existent for generating the green UC emissions in the samples with higher Yb3+ concentrations. In addition, it was observed that the temperature sensing properties of YNbO4: Er3+/Yb3+ phosphors were sensitive to both Er3+ and Yb3+ doping concentrations. Furthermore, based on the obtained temperature response of the UC luminescence phosphors, 1550 nm laser-irradiation-induced thermal effect was studied, and it was discovered that the sample temperature was very sensitive to the doping concentrations of Er3+ and Yb3+ and the excitation power.

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“…The effect of concentration quenching in a crystal doped with luminescent ions depends on the material quality 52 . .…”

Section: Discussionmentioning

confidence: 99%

Multi-photon quantum cutting in Gd2O2S:Tm3+ to enhance the photo-response of solar cells

Martín-Rodríguez

Zhang

et al. 2015

Light Sci Appl

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Conventional photoluminescence (PL) yields at most one emitted photon for each absorption event. Downconversion (or quantum cutting) materials can yield more than one photon by virtue of energy transfer processes between luminescent centers. In this work, we introduce Gd 2 O 2 S:Tm 31 as a multi-photon quantum cutter. It can convert near-infrared, visible, or ultraviolet photons into two, three, or four infrared photons of ,1800 nm, respectively. The cross-relaxation steps between Tm 31 ions that lead to quantum cutting are identified from (time-resolved) PL as a function of the Tm 31 concentration in the crystal. A model is presented that reproduces the way in which the Tm 31 concentration affects both the relative intensities of the various emission lines and the excited state dynamics and providing insight in the quantum cutting efficiency. Finally, we discuss the potential application of Gd 2 O 2 S:Tm 31 for spectral conversion to improve the efficiency of next-generation photovoltaics. Keywords: downconversion; infrared emission; quantum cutting; solar cells; spectral conversions INTRODUCTION Over the last decade, advanced luminescent materials exhibiting downconversion, also known as quantum cutting or quantum splitting, have been developed 1,2 . In this process, a high-energy photon is converted into two or more lower-energy photons, with a quantum efficiency of potentially well over 100% 3 . If the downconverted photons are in the visible range, this concept is of interest for color conversion layers in conventional lighting applications 1,2,4-6 . New exciting possibilities of downconversion to infrared (IR) photons lie in next-generation photovoltaics, aiming at minimizing the spectral mismatch losses in solar cells [7][8][9][10][11] .Spectral mismatch is the result of the broad width of the spectrum emitted by the sun. Semiconductor absorber materials absorb only photons with an energy hn higher than the band gap E g 7 . To absorb many photons and produce a large electrical current, absorber materials must therefore have a small bandgap. However, because excited charge carriers rapidly thermalize to the edges of a semiconductor's conduction and valence bands, a high voltage output requires an absorber with a large band gap. Hence, materials with low transmission losses (leading to a large current) have high thermalization losses (leading to a low voltage) and vice versa 12,13 . These spectral mismatch losses constitute the major factor defining the relatively low ShockleyQueisser limit 14 , the maximum light-to-electricity conversion efficiency of 33% in a single-junction solar cell, obtained for a band gap of approximately 1.1 eV (1100 nm) 13 .Efficiencies higher than 33% can be reached with multi-junction solar cells, where a stack of multiple absorber materials are each optimized to efficiently convert different parts of the solar spectrum to

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Upconversion Dynamics in Er³⁺‐Doped Gd₂O₂S: Influence of Excitation Power, Er³⁺ Concentration, and Defects

Cited by 70 publications

References 29 publications

Enhance the Er3+ Upconversion Luminescence by Constructing NaGdF4:Er3+@NaGdF4:Er3+ Active-Core/Active-Shell Nanocrystals

Enhance the Er3+ Upconversion Luminescence by Constructing NaGdF4:Er3+@NaGdF4:Er3+ Active-Core/Active-Shell Nanocrystals

Up-conversion luminescence, temperature sensing properties and laser-induced heating effect of Er3+/Yb3+ co-doped YNbO4 phosphors under 1550 nm excitation

Multi-photon quantum cutting in Gd2O2S:Tm3+ to enhance the photo-response of solar cells

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