Infrared luminescent properties of Na5Lu9F32 single crystals co-doped Er3+/Yb3+ grown by Bridgman method

Crystal Research and Technology

Zhang

et al. 2018

Self Cite

Tb3+/Yb3+ co‐doped Na5Lu9F32 single crystals with ≈1.0 mol% Tb3+ concentrations and various Yb3+ are prepared by Bridgman method. Several visible up‐conversion (UC) luminescence are observed following the excitation of 980 nm laser diode (LD) as well as its pump power dependence on UC emission of the crystals. The quadratic dependence of pump power on UC emission reveals that two‐photon UC processes are mainly responsible for the 486 nm and 543 nm emissions of Tb3+/Yb3+ co‐doped system in Na5Lu9F32 single crystals. It is proposed that cooperative energy transfer (CET) from two excited Yb3+ ions to the ground state of Tb3+ ions is in charge of the ≈486 nm, ≈543 nm and ≈620 nm, which are attributing to 5D4 → 7F6, 5D4 → 7F4 and 5D4 → 7F3, respectively, are obtained in Tb3+/Yb3+ doped Na5Lu9F32 single crystals. Furthermore, a favorable yellowish green light performance can be achieved with certain Yb3+ concentrations and 1.0 mol% Tb3+ co‐doped samples, and its external quantum efficiency approached to 1.25% under 5.5 W cm−2 980 nm excitation which makes further research valuable in developing processable UC materials for electro‐optical devices.

Section: Resultssupporting

confidence: 60%

Efficiently Cooperative Energy Transfer Up‐Conversion Luminescence in Tb³⁺ /Yb³⁺ Co‐Doped Cubic Na₅Lu₉F₃₂ Single Crystals by Vertical Bridgman Method

Crystal Research and Technology

Zhang

et al. 2018

Self Cite

“…Moreover, the DC energy transfer mechanism remains unknown for Tb 3+ /Yb 3+ couples in single crystal hosts. In this paper, Na 5 Lu 9 F 32 single crystal with low phonon energy (maximum phonon energy ∼440 cm –1 ) is selected to accommodate Tb 3+ and Yb 3+ ions to investigate the optical properties and DC energy transfer mechanism under visible light . Results show the current Tb 3+ /Yb 3+ doped Na 5 Lu 9 F 32 single crystal is a potential candidate to enhance the c-Si solar cell performance by the modification of solar spectrum.…”

Section: Introductionmentioning

confidence: 99%

NIR Downconversion and Energy Transfer Mechanisms in Tb³⁺/Yb³⁺ Codoped Na₅Lu₉F₃₂ Single Crystals

Zhang

et al. 2018

Inorg. Chem.

Self Cite

Tb/Yb codoped NaLuF single crystals with near-infrared (NIR) emission are achieved by an improved Bridgman approach. Energy transfer from Tb to Yb ions is affirmed by the photoluminescence (PL) emission spectra and decay curves characterization. On the basis of the analysis of energy transfer rate dependence on the Yb concentration, the interaction between Tb and Yb ions in NaLuF single crystals is confirmed through the one-to-one energy transfer process. Results demonstrate that the prepared NaLuF single crystals might be promising candidates to convert sunlight to improve the performance of the silicon solar cells.

“…Very recently, Na 5 Lu 9 F 32 fluoride single crystal was investigated as the potential up‐conversion and laser material when rare earth ions were doped in the crystal to take advantage of its chemical stability, efficient fluorescence and long lifetime for the excited states. Na 5 Lu 9 F 32 single crystal exhibiting low maximum phonon energy (≈441 cm −1 ) was grown successfully in our laboratory . The advantageous properties make Na 5 Lu 9 F 32 fluoride single crystal a favorable host material for transition metal ions.…”

Section: Introductionmentioning

confidence: 99%

Spectral Characteristics of Mn²⁺ Doped Na₅Lu₉F₃₂ Single Crystals

Physica Status Solidi (b)

et al. 2018

Self Cite

Mn 2þ ion doped Na 5 Lu 9 F 32 single crystals are grown by an improved Bridgman method. The absorption and fluorescence spectrum of single crystals in the range of 300-800 nm are measured to investigate the spectral properties. Fluorescent band centered at 550 nm was observed in the fluorescence spectrum of the crystals corresponding to the 4 T 1 ( 4 G) ! 6 A 1 ( 6 S) transition of the Mn 2þ ion. An excitation peak of 400 nm is observed in the excitation spectrum due to the charge transfer transition of electrons from the ground state to the conduction band. The calculated values for the crystal field (Dq) and Racah parameters indicate that a stable cubic crystal structure of Mn 2þ ion surrounded by eight F À ligands can be formed with the introduction of Mn 2þ ion into Na 5 Lu 9 F 32 single crystals.