Strategies to approach high performance in Cr3+-doped phosphors for high-power NIR-LED light sources

Light Science & Applications, Journal Year: 2020, Volume and Issue: 9(1)

Published: May 15, 2020

Abstract Broadband near-infrared (NIR)-emitting phosphors are key for next-generation smart NIR light sources based on blue LEDs. To achieve excellent phosphors, we propose a strategy of enhancing the crystallinity, modifying micromorphology, and maintaining valence state Cr 3+ in Ca 3 Sc 2 Si O 12 garnet (CSSG). By adding fluxes sintering reducing atmosphere, internal quantum efficiency (IQE) is greatly enhanced to 92.3%. The optimized CSSG:6%Cr exhibits thermal stability. At 150 °C, 97.4% emission at room temperature can be maintained. fabricated NIR-LED device emits high optical power 109.9 mW 520 mA. performances both achieved phosphor almost best results until now. mechanism optimization investigated. An application source demonstrated.

Language: Английский

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Enhancing Near-Infrared Photoluminescence Intensity and Spectral Properties in Yb³⁺ Codoped LiScP₂O₇:Cr³⁺

Chemistry of Materials, Journal Year: 2020, Volume and Issue: 32(6), P. 2430 - 2439

Published: Feb. 27, 2020

Near-infrared (NIR) phosphors have received increasing attention for designing novel solid-state light sources with broadband NIR output. In this work, a phosphor LiScP2O7:Cr3+ (LSP:Cr3+) is developed the emissions (750–1100 nm) completely in spectral range. Under 470 nm excitation, LSP:0.06Cr3+ shows peaking at ∼880 nm, full width half maximum (FWHM) of ∼170 and an internal quantum yield (IQY) ∼38%. Moreover, photoluminescence (PL) improvements LSP:Cr3+ are achieved by Yb3+ codoping, leading to broadened FWHM (up ∼210 nm), increased IQY (ηmax = ∼74%), reduced thermal quenching. The energy transformation processes LSP:Cr3+,Yb3+ quantitatively analyzed on basis PL lifetime QY measurements, revealing that codoping principally originate from transfer Cr3+ more efficient thermally stable emitters. Finally, phosphor-converted light-emitting diodes (pc-LEDs) fabricated combining blue LED chips, giving output power ∼36 mW photoelectric efficiency ∼12% 100 mA drive current. results suggest investigated would be promising luminescent converters pc-LED applications.

Language: Английский

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Broadband Near‐Infrared Garnet Phosphors with Near‐Unity Internal Quantum Efficiency

Advanced Optical Materials, Journal Year: 2020, Volume and Issue: 8(12)

Published: April 20, 2020

Abstract Compact near‐infrared (NIR) light sources with broad emission band are essential to enable NIR spectroscopy compatible portable devices, and phosphor‐converted emitting diodes (pc‐LEDs) efficient, low‐cost, compact sources. However, it is more challenging develop highly efficient thermally stable broadband phosphors than conventional for white LEDs. Here, a series of solid solution designed by cationic substitution in Cr 3+ activated garnet Gd 3 Sc 2 Ga O 12 reported. The internal quantum efficiency can be significantly improved nearly 100% via the ScO 6 smaller AlO octahedrons, which attributed reduction antisite defects. Moreover, phosphor optimized composition shows emission, renders as‐fabricated pc‐LED high‐power (750.8 mW) covering wavelength range 700–1000 nm. results could advance development pc‐LEDs as high‐performance miniature spectrometers.

Language: Английский

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Simultaneous Broadening and Enhancement of Cr³⁺Photoluminescence in LiIn₂SbO₆by Chemical Unit Cosubstitution: Night‐Vision and Near‐Infrared Spectroscopy Detection Applications

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(26), P. 14644 - 14649

Published: April 6, 2021

Abstract Near‐infrared (NIR)‐emitting phosphor materials have been extensively developed for optoelectronic and biomedical applications. Although Cr 3+ ‐activated phosphors widely reported, it is challenging to achieve ultra‐broad tunable NIR emission. Here, a new ultra‐broadband NIR‐emitting LiIn 2 SbO 6 :Cr with emission peak at 965 nm full‐width half maximum of 217 reported. Controllable tuning from 892 achieved by chemical unit cosubstitution [Zn 2+ –Zn ] [Li + –In ], which can be ascribed the upshift 4 T 2g energy level due strengthened crystal field. Moreover, greatly enhanced, FWHM reaches 235 nm. The as‐prepared luminescent demonstrated potential in night‐vision spectroscopy techniques. This work proves feasibility strategy ‐doped phosphors, stimulate further studies on emission‐tunable materials.

Language: Английский

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Mn²⁺‐Doped Metal Halide Perovskites: Structure, Photoluminescence, and Application

Laser & Photonics Review, Journal Year: 2020, Volume and Issue: 15(1)

Published: Nov. 30, 2020

Abstract Doping impurity ions into semiconductor luminescent materials offers a unique pathway for inducing new emission centers and enabling photoluminescence (PL) tuning. Among various luminescence materials, doping Mn 2+ metal halide perovskites becomes hot topic since demonstrate an energy transfer route from host to dopants, resulting in interesting photophysical properties. This review aims discuss the PL properties of nanocrystals or bulk crystals with different structural dimensions local environments (MnX 4 2– tetrahedron, MnX 6 octahedron, shortest Mn─Mn distance). In this regard, effects on their modifications are summarized. Variable ion exchange dynamics, increased intensity, enhanced stability induced by analyzed. These results also provide beneficial insights applications doped perovskites. Finally, present challenges ‐doped elaborated.

Language: Английский

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Near‐Infrared Light‐Emitting Diodes utilizing a Europium‐Activated Calcium Oxide Phosphor with External Quantum Efficiency of up to 54.7%

Advanced Materials, Journal Year: 2022, Volume and Issue: 34(26)

Published: April 15, 2022

Near-infrared (NIR) luminescence materials with broadband emissions are necessary for the development of light-emitting diodes (LEDs) based light sources. However, most known NIR-emitting limited by their low external quantum efficiency. This work demonstrates how photoluminescence efficiency europium-activated calcium oxide (CaO:Eu) NIR phosphor can be significantly improved and stabilized at operating temperatures LEDs. A carbon paper wrapping technology is innovatively developed used during solid-state sintering to promote reduction Eu3+ into Eu2+ . In parallel, oxygen vacancies in CaO lattice repaired utilizing GeO2 decomposition. Through this process, a record-high 54.7% 740 nm obtained thermal stability greatly from 57% 90% 125 °C. The as-fabricated NIR-LEDs reach record photoelectric (100 [email protected]%) output power mA @ 319.5 mW). discovery high-performance phosphors will open new research avenues LED sources variety photonics applications.

Language: Английский

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Cr³⁺‐Doped Sc‐Based Fluoride Enabling Highly Efficient Near Infrared Luminescence: A Case Study of K₂NaScF₆:Cr³⁺

Laser & Photonics Review, Journal Year: 2020, Volume and Issue: 15(2)

Published: Dec. 23, 2020

Abstract The development of highly efficient and thermally stable broadband near‐infrared (NIR) luminescence materials is a great challenge to advance the next‐generation smart NIR light source. Benefitting from low phonon energy relatively weak electron coupling effect fluoride, K 2 NaScF 6 :Cr 3+ phosphor designed obtained, which demonstrates full width at half maximum 100 nm peaking ≈765 nm. Upon blue excitation, exhibits high quantum efficiency 74% its emission intensity 150 °C can keep 89.6% initial value 25 °C. An output power 159.72 mW (input electric power, 1094 mW) with photoelectric conversion ≈14.60%, light‐emitting diode (LED) device presented based on this phosphor. Furthermore, applying high‐power phosphor‐converted LED as lighting source, clear quick veins imaging recognition in fingers, palm, wrist, arm human hand are first realized, suggesting has promise practical applications.

Language: Английский

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Penetrating Biological Tissue Using Light-Emitting Diodes with a Highly Efficient Near-Infrared ScBO₃:Cr³⁺ Phosphor

Chemistry of Materials, Journal Year: 2020, Volume and Issue: 32(5), P. 2166 - 2171

Published: Feb. 5, 2020

Recently, infrared (IR) light-emitting diodes (LEDs) have attracted considerable interest in the research field worldwide. IR phosphors, basic materials utilized LEDs, become a hotspot as well. Here, we introduce high-quantum-efficiency ScBO3:Cr3+ phosphor, which provides spectral range of emission from 700 to 1000 nm with peak maximum at 800 nm. Electron paramagnetic resonance spectroscopy, high element selectivity, was used elucidate unusual small photoluminescence spectrum. Phonon structure and electron–lattice interaction were well observed discussed via temperature-dependent measurements. Moreover, quantum efficiency 72.8% achieved. To evaluate their potential practical application, phosphor-converted LED packages designed, revealed stability output power 39.11 mW. Furthermore, fabricated demonstrated remarkable ability penetrate biological tissues. This study insights into luminescent properties applications LEDs.

Language: Английский

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Chromium Ion Pair Luminescence: A Strategy in Broadband Near-Infrared Light-Emitting Diode Design

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(45), P. 19058 - 19066

Published: Nov. 4, 2021

Portable near-infrared (NIR) light sources are in high demand for applications spectroscopy, night vision, bioimaging, and many others. Typical phosphor designs feature isolated Cr3+ ion centers, it is challenging to design broadband NIR phosphors based on Cr3+–Cr3+ pairs. Here, we explore the solid-solution series SrAl11.88–xGaxO19:0.12Cr3+ (x = 0, 2, 4, 6, 8, 10, 12) as featuring pairs evaluate structure–property relations within series. We establish incorporation of Ga magentoplumbite-type structure at five distinct crystallographic sites effect this pair proximity. Electron paramagnetic measurements reveal presence both pairs, resulting luminescence approximately 650–1050 nm. Unexpectedly, origin with a peak range 740–820 nm related pair. demonstrate application SrAl5.88Ga6O19:0.12Cr3+ phosphor, which possesses an internal quantum efficiency ∼85%, radiant flux ∼95 mW, zero thermal quenching up 500 K. This work provides further understanding spectral shifts solid solutions particular magentoplumbites promising next-generation host systems.

Language: Английский

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Two-site Cr³⁺ occupation in the MgTa₂O₆:Cr³⁺ phosphor toward broad-band near-infrared emission for vessel visualization

Journal of Materials Chemistry C, Journal Year: 2020, Volume and Issue: 8(27), P. 9322 - 9328

Published: Jan. 1, 2020

Cr³⁺ ions in MgTa₂O₆ located the two six-coordinated crystallographic sites of Mg²⁺ and Ta⁵⁺ enable broad-band near-infrared emission.

Language: Английский

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