Upconversion laser emission from Yb^3+-sensitized Tm^3+ in BaY_2F_8

Thrash, Robert J.; Johnson, L. F.

doi:10.1364/josab.11.000881

Cited by 117 publications

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“…This means that the cross-relaxation rate of the 1 G 4 level in a nearest-neighbor pair is 1/0.16 ms, 6603 faster than radiative decay. Such fast cross-relaxation rates explain why in upconversion experiments only low Tm 31 concentrations of no higher than 1% yield bright blue upconversion emission [44][45][46] .…”

Section: Resultsmentioning

confidence: 98%

“…At low Tm 31 29,44 , which would lead to similar downconversion schemes, except that the 3 H 5 level is directly populated in the first step of the sequence of cross-relaxation steps. Because we experimentally observe 3 H 5 emission only at the highest concentrations, the dominant first cross-relaxation process is probably ( 1 G 4 , 3 H 6 ) R ( 3 F 2,3 , 3 F 4 ).…”

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: 98%

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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“…Er 3+ , Tm 3+ , Nd 3+ , and Ho 3+ are the most frequently used activator ions for upconversion processes. [6][7][8][9] Very often, Yb 3+ is used as a sensitizer. This ion plays a very special part among the lanthanides because of its (4f) 13 electron configuration.…”

Section: Introductionmentioning

confidence: 99%

Exchange-Induced Upconversion in Rb₂MnCl₄:Yb³⁺

2002

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Crystals of Yb 3+ doped Rb 2 MnCl 4 exhibit very intense yellow-orange Mn 2+ 4 T 1g f 6 A 1g upconversion luminescence under near-infrared 2 F 7/2 f 2 F 5/2 Yb 3+ excitation around 1 µm at 15 K. Excitation with 10 ns pulses indicates that the upconversion process consists of a sequence of ground-state and excited-state absorption steps. The upconversion mechanism is cooperative, involving both Yb 3+ and Mn 2+ ions in the crystal, and we postulate an exchange mechanism between adjacent Yb 3+ and Mn 2+ ions to account for the unusually high efficiency of the process. The efficiency of the upconversion process is dependent on the nature of the Yb 3+ -Mn 2+ connectivity. The upconversion in Rb 2 MnCl 4 :Yb 3+ , with a linear Yb 3+ -Cl --Mn 2+ arrangement, is 3 orders of magnitude more efficient than in the Yb 3+ -(Br -) 3 -Mn 2+ arrangement of face-sharing octahedra in CsMnBr 3 :Yb 3+ .

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“…In particular, they have lower phonon energies than oxides leading to the possibility of both mid-infrared (mid-IR) [1] and upconversion [2] lasers. Incorporating the fluoride host in an optical waveguide geometry can also offer low thresholds and high efficiencies, increasing the potential for continuous wave (CW) operation at room temperature and at relatively high power levels.…”

Section: Introductionmentioning

confidence: 99%

Low phonon energy, Nd:LaF/sub 3/ channel waveguide lasers fabricated by molecular beam epitaxy

Bhutta

Chardon

Shepherd

et al. 2001

IEEE J. Quantum Electron.

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Abstract-We report the first fabrication and laser operation of channel waveguides based on LaF 3 planar thin films grown by molecular beam epitaxy. To our knowledge, this is the lowest phonon energy dielectric material to have shown guided-wave laser operation to date. A full characterization, in terms of spectroscopy, laser results, and propagation losses, is given for the planar thin films upon which the channel waveguides are based. Two channel-fabrication methods are then described, the first involves ion milling and the second takes the novel approach of using a photo-definable polymer overlay. Laser operation in Nd-doped samples is demonstrated at 1.06, 1.05, and 1.3 m, and the potential for mid-infrared laser sources based on such guides is discussed.

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Upconversion laser emission from Yb^3+-sensitized Tm^3+ in BaY_2F_8

Cited by 117 publications

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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

Exchange-Induced Upconversion in Rb₂MnCl₄:Yb³⁺

Low phonon energy, Nd:LaF/sub 3/ channel waveguide lasers fabricated by molecular beam epitaxy

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Upconversion laser emission from Yb^3+-sensitized Tm^3+ in BaY_2F_8

Cited by 117 publications

References 0 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

Exchange-Induced Upconversion in Rb2MnCl4:Yb3+

Low phonon energy, Nd:LaF/sub 3/ channel waveguide lasers fabricated by molecular beam epitaxy

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Exchange-Induced Upconversion in Rb₂MnCl₄:Yb³⁺