Insights into the energy transfer mechanism in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mrow><mml:mi>Ce</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:mo>−</mml:mo><mml:msup><mml:mrow><mml:mi>Yb</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn><mml:mo>+</mml:mo></mml:mrow></mml:msup></mml:math>codoped YAG phosphors

Yu, Dechao; Rabouw, Freddy T.; Boon, W. Q.; Kieboom, T.; Ye, Shi; Zhang, Q. Y.; Meijerink, Andries

doi:10.1103/physrevb.90.165126

Cited by 86 publications

(70 citation statements)

References 42 publications

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“…Fast non-radiative 3 Figure 1c shows that for increasing Tm 31 concentration, the decay of the 3 H 4 level rapidly becomes faster, consistent with crossrelaxation (pathway III in Figure 1b). We fit the decay curve for 0.1% Tm 31 to a single exponential, assuming no cross-relaxation, and obtain an intrinsic lifetime of the 3 H 4 level of t 0 5 255 ms. Next we assume that at higher Tm 31 concentrations, cross-relaxation can take place via dipole-dipole coupling in pairs of Tm 31 ions, yielding a cross-relaxation rate C xr for a single pair proportional to the inverse sixth power of the separation r between the ions 17,22,39,40 :…”

Section: Resultsmentioning

confidence: 99%

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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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Section: Resultsmentioning

confidence: 99%

“…We fit the decay curve for 1% Tm 31 to an analytical model that assumes a random substitution of Tm 31 for Gd 31 in the Gd 2 O 2 S crystal 39,40 :…”

Section: Resultsmentioning

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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“…In a more sophisticated model one could add a thermal dependency of the energy transfer due to spectral broadening. Furthermore it would be possible to do a Monte Carlo Modelling of the energy transfer to incorporate the statistical distribution of the two inequivalent Eu 2+ ions and calculate out of the distribution of the distances an inhomogeneous energy-transfer function [17]. …”

Section: Kinetic Modelmentioning

confidence: 99%

Thermal and concentration dependent energy transfer of Eu^2+ in SrAl_2O_4

Bierwagen

Yoon

Gartmann³

et al. 2016

Opt. Mater. Express

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SrAl 2 O 4 doped with europium and dysprosium is a powerful and widely used afterglow material. Within this material strontium is found in two crystallographic different sites. Due to the similar ion radii and same charge, Eu 2+ -ions can occupy both sites, resulting in two different Eu 2+ -ions, one emitting in the blue and one in the green spectral range. The blue emission is thermally quenched at room temperature. In this paper we investigate the energy transfer between different Eu ions depending on the concentration and temperature using two different approaches: lifetime measurements and integrated intensity. We find an activation energy for the thermal quenching of the blue emission of 0.195 ± 0.023 eV and a critical radius for the energy transfer of 3.0 ± 0.5 nm. These results can help in designing better afterglow materials due to the fact that with energy transfer parts of the lost emission in the blue region at room temperature can be converted to the green site.

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“…Notice that the variation of integrated emission intensity differs from that of YAG:Ce 3+ ,Yb 3+ where although the Ce 3+ intensity also decreases with temperature, the Yb 3+ emission intensity increases up to ~150 K and then decreases. 9 The decrease was attributed to excitation migration to killer sites 9 attributed to Yb 2+ -Yb 3+ pairs. 8 In Figure 11 …”

Section: Temperature-dependence Of Emission Lifetime and Emissionmentioning

confidence: 97%

Spectral Properties and Energy Transfer between Ce³⁺ and Yb³⁺ in the Ca₃Sc₂Si₃O₁₂ Host: Is It an Electron Transfer Mechanism?

et al. 2016

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The downshifting from Ce(3+) blue emission to Yb(3+) near-infrared emission has been studied in the garnet host Ca2.8-2xCe0.1YbxNa0.1+xSc2Si3O12 (x = 0-0.36). The downshifting does not involve quantum cutting, but one incident blue photon is transferred from Ce(3+) to Yb(3+) with an energy transfer efficiency up to 90% when x = 0.36 for the Yb(3+) dopant ion. For x ≤ 0.15, a multiphonon-assisted electric dipole-electric quadrupole mechanism of energy transfer dominates, while for the highest concentration of Yb(3+) employed, the electron transfer mechanism is confirmed. A temperature-dependent increase of the Ce(3+) → Yb(3+) energy transfer rate does not exclusively indicate the electron transfer mechanism. The application of the material to solar energy conversion is indicated.

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Insights into the energy transfer mechanism inCe3+−Yb3+codoped YAG phosphors

Cited by 86 publications

References 42 publications

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

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

Thermal and concentration dependent energy transfer of Eu^2+ in SrAl_2O_4

Spectral Properties and Energy Transfer between Ce³⁺ and Yb³⁺ in the Ca₃Sc₂Si₃O₁₂ Host: Is It an Electron Transfer Mechanism?

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Insights into the energy transfer mechanism inCe3+−Yb3+codoped YAG phosphors

Cited by 86 publications

References 42 publications

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

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

Thermal and concentration dependent energy transfer of Eu^2+ in SrAl_2O_4

Spectral Properties and Energy Transfer between Ce3+ and Yb3+ in the Ca3Sc2Si3O12 Host: Is It an Electron Transfer Mechanism?

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Spectral Properties and Energy Transfer between Ce³⁺ and Yb³⁺ in the Ca₃Sc₂Si₃O₁₂ Host: Is It an Electron Transfer Mechanism?