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

Light Science & Applications, Год журнала: 2020, Номер 9(1)

Опубликована: Май 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.

Язык: Английский

---

Divalent europium-doped near-infrared-emitting phosphor for light-emitting diodes

Nature Communications, Год журнала: 2019, Номер 10(1)

Опубликована: Ноя. 20, 2019

Abstract Near-infrared luminescent materials exhibit unique photophysical properties that make them crucial components in photonic, optoelectronic and biological applications. As broadband near infrared phosphors activated by transition metal elements are already widely reported, there is a challenge for next-generation discovery introducing rare earth activators with 4 f -5 d transition. Here, we report an unprecedented phosphor K 3 LuSi 2 O 7 :Eu 2+ gives emission band centered at 740 nm full-width half maximum of 160 upon 460 blue light excitation. Combined structural spectral characterizations reveal selective site occupation divalent europium LuO 6 K2O polyhedrons small coordination numbers, leading to the unexpected emission. The fabricated phosphor-converted light-emitting diodes have great potential as non-visible source. Our work provides design principle europium-doped inorganic solid-state could inspire future studies further explore near-infrared diodes.

Язык: Английский

---

Two-Site Occupation for Exploring Ultra-Broadband Near-Infrared Phosphor—Double-Perovskite La₂MgZrO₆:Cr³⁺

Chemistry of Materials, Год журнала: 2019, Номер 31(14), С. 5245 - 5253

Опубликована: Июнь 28, 2019

The near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) have great potential in food industry and medical fields. For applications based on NIR spectroscopy, the next generation of pc-LEDs is a high demand spectrum with much broader full width at half-maximum (fwhm), which triggers discovery novel broadband phosphors. In this work, Cr3+-doped La2MgZrO6 (LMZ) was successfully synthesized by conventional solid-state method reducing atmosphere, double-perovskite oxide LMZ two distorted octahedral sites finally led to an ultra-broadband Cr3+ emission centered 825 nm extremely large fwhm 210 internal quantum efficiency ∼58%. experimental data theoretical calculation confirmed that available different crystal field environments contributed emission. parameters, decay time, temperature-dependent photoluminescence properties were investigated discussed further understand luminescence LMZ:Cr. suitability title phosphor multifunctional demonstrated pumping it blue, green, and/or red LED chips.

Язык: Английский

---

Super Broadband Near-Infrared Phosphors with High Radiant Flux as Future Light Sources for Spectroscopy Applications

ACS Energy Letters, Год журнала: 2018, Номер 3(11), С. 2679 - 2684

Опубликована: Окт. 8, 2018

The near-infrared (NIR) light source is desirable for real-time nondestructive examination applications, which include the analysis of foodstuffs, health monitoring, iris recognition, and infrared cameras. emission spectra such an should also be as broad possible effective performance, in view fact that absorption reflection by organic elements present foodstuffs human fall blue NIR regions electromagnetic spectrum, respectively. In this letter, a light-emitting diode (LED) excitable super broadband phosphor developed with high fwhm 330 nm radiant flux 18.2 mW first time. observation super-broad-band luminescence from two distinct centers studied evidenced electron paramagnetic resonance, X-ray near-edge structure, steady-state luminescence, time-resolved at ambient high-pressure environments. Finally, mechanism discussed relevant configurational coordinate diagrams.

Язык: Английский

---

Cr³⁺‐Doped Broadband NIR Garnet Phosphor with Enhanced Luminescence and its Application in NIR Spectroscopy

Advanced Optical Materials, Год журнала: 2019, Номер 7(12)

Опубликована: Апрель 16, 2019

Abstract Broadband near‐infrared (NIR) phosphor‐converted light emitting diode (pc‐LED) is demanded for wearable biosensing devices, but it suffers from low efficiency and radiance. This study reports a broadband NIR Ca 3‐ x Lu Hf 2 Al 2+ Si 1− O 12 :Cr 3+ garnet phosphor with emission intensity enhanced by 81.5 times. Chemical unit co‐substitution of [Lu −Al ] [Ca −Si 4+ responsible the luminescence enhancement further alters crystal structure electronic properties garnet. Using optimized phosphor, pc‐LED photoelectric efficiencies 21.28%@10 mA, 15.75%@100 mA output powers 46.09 mW@100 54.29 mW@130 fabricated. The high power observed to penetrate upper arms (≈8 cm). For application in spectroscopy, used as source measure transmission spectra water, alcohol, bovine hemoglobin solution. These results indicate be promising candidate pc‐LED.

Язык: Английский

---

Highly efficient and thermally stable Cr3+-activated silicate phosphors for broadband near-infrared LED applications

Chemical Engineering Journal, Год журнала: 2019, Номер 383, С. 123108 - 123108

Опубликована: Окт. 9, 2019

Язык: Английский

---

Advances in Chromium‐Activated Phosphors for Near‐Infrared Light Sources

Laser & Photonics Review, Год журнала: 2022, Номер 16(11)

Опубликована: Авг. 7, 2022

Abstract Cr 3+ /Cr 4+ ‐activated near‐infrared (NIR) luminescent materials have attracted extensive attention owing to their tunable emission wavelength and widespread applications in plant growth, food analysis, biomedical imaging, night vision, so on. Plenty of excellent NIR are developed by introducing ion various inorganic hosts. Herein, the effect crystal field on luminescence combining Tanabe–Sugano energy level diagram configuration coordinate model is discussed. Research progress ‐doped materials, including phosphors designed from structural models with octahedral, tetrahedral, other coordination types, then outlined. The properties more than 200 kinds summarized. In particular, several strategies for tuning wavelength, broadening band, enhancing efficiency, improving thermal stability, listed. Finally, current challenges future prospects research presented. This review will contribute a deeper understanding not only mechanism but also chromium‐doped as develop better performance explore applications.

Язык: Английский

---

Double perovskite Cs₂AgInCl₆:Cr³⁺: broadband and near-infrared luminescent materials

Inorganic Chemistry Frontiers, Год журнала: 2019, Номер 6(12), С. 3621 - 3628

Опубликована: Янв. 1, 2019

A Cr³⁺-doped halide double perovskite Cs₂AgInCl₆:Cr³⁺ is first reported which exhibits a broad near-infrared emission ranging from 850 to 1350 nm centered at 1010 with FWHM of 180 nm.

Язык: Английский

---

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

Chemistry of Materials, Год журнала: 2020, Номер 32(6), С. 2430 - 2439

Опубликована: Фев. 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.

Язык: Английский

---

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

Advanced Optical Materials, Год журнала: 2020, Номер 8(12)

Опубликована: Апрель 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.

Язык: Английский

---