Perovskite light-emitting diodes

Nature Electronics, Journal Year: 2022, Volume and Issue: 5(4), P. 203 - 216

Published: April 21, 2022

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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Blue LED-pumped intense short-wave infrared luminescence based on Cr3+-Yb3+-co-doped phosphors

Light Science & Applications, Journal Year: 2022, Volume and Issue: 11(1)

Published: May 13, 2022

Abstract The growing demand for spectroscopy applications in the areas of agriculture, retail and healthcare has led to extensive research on infrared light sources. ability phosphors absorb blue from commercial LED convert excitation energy into long-wavelength luminescence is crucial design cost-effective high-performance phosphor-converted LEDs. However, lack ideal blue-pumped short-wave (SWIR) with an emission peak longer than 900 nm greatly limits development SWIR LEDs using converter technology. Here we have developed a series SWIR-emitting materials high efficiency excellent thermal stability by co-doping Cr 3+ -Yb ion pairs Lu 0.2 Sc 0.8 BO 3 host materials. Benefitting strong absorption waveband very efficient →Yb transfer, as-synthesized :Cr ,Yb phosphor emits intense 900–1200 Yb under at ~460 nm. optimized presents internal quantum yield 73.6% intensity 100 °C can still keep 88.4% starting value 25 °C. prototype device based exhibits exceptional performance, delivering radiant power 18.4 mW 9.3% blue-to-SWIR conversion 5.0% electricity-to-SWIR 120 mA driving current. Moreover, illumination high-power LED, covert information identification night vision lighting been realized, demonstrating bright prospect practical applications.

Language: Английский

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Polyatomic molecules with emission quantum yields >20% enable efficient organic light-emitting diodes in the NIR(II) window

Nature Photonics, Journal Year: 2022, Volume and Issue: 16(12), P. 843 - 850

Published: Oct. 10, 2022

Language: Английский

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Achieving High Quantum Efficiency Broadband NIR Mg₄Ta₂O₉:Cr³⁺ Phosphor Through Lithium‐Ion Compensation

Advanced Materials, Journal Year: 2023, Volume and Issue: 35(22)

Published: March 3, 2023

Ultra-efficient broadband near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) are urgently needed to improve the detection sensitivity and spatial resolution of current smart NIR spectroscopy-based techniques. Nonetheless, performance pc-LED has severely limited owing external quantum efficiency (EQE) bottleneck materials. Herein, a blue LED excitable Cr3+ -doped tetramagnesium ditantalate (Mg4 Ta2 O9 , MT) phosphor is advantageously modified through lithium ion as key efficient emitter achieve high optical output power light source. The emission spectrum encompasses 700-1300 nm electromagnetic first biological window (λmax = 842 nm) with full-width at half-maximum (FWHM) ≈2280 cm-1 (≈167 nm), achieves record EQE 61.25% detected 450 excitation Li-ion compensation. A prototype fabricated MT:Cr3+ Li+ evaluate its potential practical application, which reveals an 53.22 mW driving 100 mA, photoelectric conversion 25.09% 10 mA. This work provides ultra-efficient luminescent material, shows great promise in applications presents novel option for next-generation high-power compact sources.

Language: Английский

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Double boron-embedded multiresonant thermally activated delayed fluorescent materials for organic light-emitting diodes

Communications Chemistry, Journal Year: 2022, Volume and Issue: 5(1)

Published: Nov. 10, 2022

The subclass of multi resonant thermally activated delayed fluorescent emitters (MR-TADF) containing boron atoms has garnered significant attention in the field organic light emitting diode (OLED) research. Among boron-based MR-TADF emitters, double boron-embedded (DB-MR-TADF) show excellent electroluminescence performances with high photoluminescence quantum yields, narrow band emission, and beneficially small singlet-triplet energy levels all full-color gamut regions. This article reviews recent progress DB-MR-TADF particular to molecular design concepts, synthetic routes, optoelectronic properties, OLED performance, giving future prospects for real-world applications.

Language: Английский

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Laser-driven broadband near-infrared light source with watt-level output

Nature Photonics, Journal Year: 2024, Volume and Issue: 18(6), P. 562 - 568

Published: March 1, 2024

Language: Английский

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A Multifunctional Additive Strategy Enables Efficient Pure‐Blue Perovskite Light‐Emitting Diodes

Advanced Materials, Journal Year: 2023, Volume and Issue: 35(35)

Published: May 11, 2023

Lead halide perovskites have shown exceptional performance in light-emitting devices (PeLEDs), particularly producing significant electroluminescence sky-blue to near-infrared wavelengths. However, PeLEDs emitting pure-blue light at 465-475 nm are still not satisfactory. Herein, efficient and stable reported by controlling phase distribution, passivation of defects, as well surface modifications using multifunctional phenylethylammonium trifluoroacetate (PEATFA) reduced-dimensional p-F-PEA2 Csn-1 Pbn (Br0.55 Cl0.45 )3n+1 polycrystalline perovskite films. Compared with 4-fluorophenylethylammonium (p-F-PEA+ ) the pristine films, (PEA+ has lower adsorption energy while interacting perovskites, resulting large-n low-dimensional which can greatly facilitate charge transport within The interaction between CO group (TFA- significantly reduces defects Additionally, electron-giving CF3 TFA- uplifts potential smooth electronic injection devices. additive strategy leads elevated radiative recombination carrier films As a result, exhibit maximum external quantum efficiency (EQE) 11.87% 468 spectral output, highest date for PeLEDs. Thus, this study extends way high-efficiency LED polycrystal

Language: Английский

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Broadband Short-Wave Infrared-Emitting MgGa₂O₄:Cr³⁺, Ni²⁺ Phosphor with Near-Unity Internal Quantum Efficiency and High Thermal Stability for Light-Emitting Diode Applications

ACS Applied Materials & Interfaces, Journal Year: 2023, Volume and Issue: 15(27), P. 32580 - 32588

Published: June 29, 2023

Blue InGaN chip-pumped short-wave infrared (SWIR) emitters have aroused tremendous attention and shown emerging applications in diverse fields such as healthcare, retail, agriculture. However, discovering blue light-emitting diode (LED)-pumped SWIR phosphors with a central emission wavelength over 1000 nm remains significant challenge. Herein, we demonstrate the efficient broadband luminescence of Ni2+ by simultaneously incorporating Cr3+ ions into MgGa2O4 lattice, sensitizer emitter. Because strong light absorption high energy transfer efficiency to Ni2+, obtained MgGa2O4:Cr3+, show intense peak at 1260 full width half maximum (FWHM) 222 under excitation light. The optimized phosphor presents an ultra-high photoluminescence quantum 96.5% outstanding thermal stability (67.9%@150 °C). A source has been fabricated through combination prepared commercial 450 LED chip, delivering radiant power 14.9 mW 150 mA input current. This work not only demonstrates feasibility developing high-power using converter technology but also new insights importance technology.

Language: Английский

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Single‐Site Occupancy of Eu²⁺ in Multiple Cations Enables Efficient Ultra‐Broadband Visible to Near‐Infrared Luminescence

Laser & Photonics Review, Journal Year: 2023, Volume and Issue: 17(5)

Published: Jan. 29, 2023

Abstract An important challenge in the research and development of compact near‐infrared (NIR) light sources is discovery new efficient ultra‐broadband NIR luminescent materials to replace conventional Cr 3+ ‐doped compounds. Herein, this work reports a divalent europium‐doped Ba 3 GeO 4 Br 2 phosphor that exhibits high photoluminescence quantum yield 48.8% an ultra‐broad emission band ranging continuously from 500 1100 nm (full width at half maximum = 202 nm) under near‐ultraviolet or blue excitation. A strategy embedding alumina crucible purity graphite devised deployed during solid‐state sintering facilitate conversion Eu into 2+ . Theoretical calculations, structural refinement, spectral analysis demonstrate visible :Eu originates ions occupying distorted Ba3O polyhedra lattice. The as‐prepared phosphor‐converted light‐emitting diode device achieves optical output power 30.1 mW@100 mA (520–1100 photoelectric efficiency 22%@100 (350–1100 nm). Experiments on tissue penetration imaging illustrate its application detection food quality testing appears promising.

Language: Английский

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