Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 46
·16280-16287
·
IF 6.4
Zhenzhen Yu,Zhenyang Liu,Mingjun Chen,Jinxing Zhao,Chaoqi Hao,You Zhang,Fenghe Wang,Guoyi Dong,Li Guan,Xu Li
It is challenging to pursue brighter and more efficient light-emitting diodes (LEDs) based on carbon dot (CD) emitting layers. In this study, we present a novel approach to successfully push the boundaries of CD-based LEDs forward remarkably. Firstly, by utilizing a modified method, we successfully synthesized CDs. Then the charge balance of this device was effectively optimized by blending the renowned hole transport material, 4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP) with CDs as an emitting layer. The fusion of these materials resulted in hybrid CDs exhibiting a pronounced P-type conductivity, leading to a significant surge in hole carrier density. This enhancement in conductivity is pivotal as it amplifies the efficiency of hole injection, a critical factor in LED brightness. To further refine our design, we doped a ZnMgO electron transport layer with polyvinyl pyrrolidone, achieving a meticulous moderation in the carrier transport rate. This intricate balance ensures optimal interaction between hole and electron injections. As a result of our comprehensive research and innovative interventions, the optimized LED device radiated with an extraordinary brightness of 505 cd m−2, combined with a low turn-on voltage of 2.5 eV. This development undeniably marks a significant milestone in the evolution of all solution CD devices.
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2022
·
IF 4.132
Yuhang Wu,Guocong Ma,Anying Zhang,Weiwen Gu,Jianfei Wei,Rui Wang
Environmentally friendly polyethylene terephthalate-based carbon dots (PET-CDs) with ultrahigh fluorescence quantum yield were prepared with waste PET textiles as raw materials. First, oligomers were prepared from the reaction of waste PET textile and ethylene glycol by the microwave method. Then, the mixture without isolation and purification as well as pyromellitic acid and urea were adopted as precursors for the preparation of PET-CDs by the hydrothermal method. It was found that the as-prepared PET-CDs had a spherical structure with an average particle size of 2.8 nm. The carbon core of PET-CDs was a graphene-like structure doped with nitrogen atoms in the form of pyrrole nitrogen and the surface contained −NH2, which is convenient for modification and functionalization with various materials in the form of chemical bonds. The as-prepared PET-CDs exhibit excitation-independent emission properties in the range from 340 to 440 nm, and the best excitation and emission wavelengths of PET-CDs are 406 and 485 nm, respectively, while the fluorescence quantum yield is 97.3%. In terms of the application, the as-prepared PET-CDs could be adopted as a fluorescence probe for the detection of Fe3+, and the limit of detection is as low as 0.2 μmol/L. The mechanism of PET-CDs by Fe3+ was found to be the static quenching mechanism. In addition, PET-CDs can be used in LEDs and fluorescent anticounterfeiting.
研究领域:
材料科学
·
环境科学
·
纳米技术
·
分析化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Science Advances
·
2025
·Vol. 11
·期 7
·
IF 12.5
Ligang Wang,Zher Ying Ooi,Feng-Yan Jia,Yuqi Sun,Yun Liu,Linjie Dai,Junzhi Ye,Jincan Zhang,Hio-Ieng Un,Yu-Hsien Chiang,Sanyang Han,Alessandro James Mirabelli,Miguel Anaya,Zhilong Zhang,Yang Lu,Chen Zou,Baodan Zhao,Dawei Di,Xiaodong Yang,Dengyang Guo,Yu Tan,Hao Dong,Shaocheng Liu,Tianjun Liu,Huanping Zhou,Samuel D. Stranks,Ling-Dong Sun,Chun-Hua Yan,Richard H. Friend
Colloidal quantum dots (QDs) have illuminated computer monitors and television screens due to their fascinating color-tunable properties depending on the size. Here, the electroluminescence (EL) wavelength of perovskite LEDs was tuned via the atomic layer number (ALN) of nanoplates (NPs) instead of the “size” in conventional QDs. We demonstrated efficient LEDs with controllably tailored emission from n = 3, 4, 5, and ≥7 ALN perovskite NPs with specific and discrete major peaks at 607, 638, 669, and 728 nanometers. These LEDs demonstrated peak external quantum efficiency (EQE) of 26.8% and high wavelength reproducibility with less than 1 to 2 nm difference between batches. High color stability without observable EL spectral change and operating stability with the best T50 of 267 minutes at 1.0 milliampere per square centimeter was also achieved. This work demonstrates a concept of tailoring specific ALN emission with fixed wavelengths, shedding light on efficient, emission-discrete, and color-stable LEDs for next-generation display.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Lanjiao Li,Ying Chen,Rongfei Wei,Siyu Guo,Xiangling Tian,Fangfang Hu,Hai Guo
Near-infrared phosphor-converted light-emitting diodes (NIR pc-LEDs) are playing an increasingly important role in the spectroscopy technology fields. Developing high-performance NIR-emitting phosphors is of immense significance for advancing NIR pc-LEDs. Herein, the approach of cationic substitution of Ca 2+ by Mg 2+ was designed in Ca 4 ZrGe 3 O 12 :Cr 3+ . Remarkably enhanced NIR emission and strikingly improved thermal stability are realized. The luminescence intensity at 423 K compared with that of room temperature ascends from 45.67 % to 72.81 %. Moreover, the representative sample was assembled to a NIR pc-LED with favorable output power and photoelectric conversion efficiency by combining a commercial 470 nm blue chip. The packaged LED demonstrates the feasibility of practical applications in night vision, biological imaging, and fruit detection. The above findings verify the potential prospect of Ca 4- x Mg x ZrGe 3 O 12 :Cr 3+ phosphor for the utilizations in NIR light sources.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
ChemPhotoChem
·
2024
·
IF 3
Lulu Wei,Shubing Tian,Mingze Sun,Ruili Song,Yunhu Wang,Mingming Zhang,Lei Wang,Zhanhua Wei,Jun Xing
Graphical The influence of perovskite components, preparation conditions, and device structures on the spectral stability of mixed-halide perovskite blue LED is investigated systematically. Among these factors, A-site cations, annealing temperature and the content of the passivator affect the spectral stability significantly. After optimization, a spectra-stable and efficient mixed-halide perovskite blue LED is successfully fabricated. Metal mixed-halide perovskite has demonstrated considerable potential in the development of solution-treated blue light-emitting diodes (LEDs) with high external quantum efficiency, excellent color purity, and tunable wavelength. However, the severe phase segregation of mixed-halide perovskite under bias voltage would lead to the spectral instability of LEDs. Therefore, suppressing phase segregation of Br/Cl perovskite towards spectrally stable blue perovskite LEDs (PeLEDs) is a big challenge. In this work, we systematically explore the influence of perovskite component, preparation conditions, and device structures on the spectral stability of PeLEDs. We have observed that the stable spectra increased the proportion of Cs in the A-site cations, passivator, and the annealing temperature of perovskite films. Finally, we achieve a spectra-stable and high-performance blue PeLED under optimized conditions. Our findings provide important guidance for preparing spectrally stable PeLEDs.
研究领域:
材料科学
·
光电工程
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2020
·
IF 1.943
Xiangjia Meng,Shuai Huang,Mengmeng Shang
Red-emitting phosphors have attracted considerable interest for their applications in warm white light-emitting diodes (LEDs). A series of novel red emitting Eu 3+ -doped Ba 2 GdVO 6 phosphors were prepared by a solid-state reaction annealed at 1300 °C for 6 h. Under the excitation of blue light (465 nm), Ba 2 GdVO 6 :Eu 3+ phosphors emit pure red light. The critical distance at which concentration occurs is determined to be 8.7 Å when the doping concentration reached up to 20 mol%. More importantly, the as-prepared Ba 2 GdVO 6 :20%Eu 3+ phosphor exhibit good thermal stability. The PL intensity at 150 °C remains 72% of its initial intensity at room temperature. The preliminary studies show that the Ba 2 GdVO 6 :Eu 3+ might be a promising red material for application in blue light converted warm white LED.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
KEY ENGINEERING MATERIALS
·
2016
·
IF 0
D.C. Huang,You Fu Zhou,Chao Quan,Wen Tao Xu
New luminescent oxynitridosilicates doped with Eu2+ and Ce3+ have been synthesized by solid state reaction method at 1450oC. The host has the general formula La1-ySr1-xSiO3N: (yCe3+, xEu2+), which presents greenish-yellow or orange photoluminescence under UV/blue excitation. Remarkable long wavelength emissions centered above 565 nm were observed for the Ce3+ activated oxynitridosilicates, with compositions LaSrSiO3N:0.02Ce3+, and LaSrSiO3N:(0.02Ce3+, 0.02Eu2+) for 598 nm due to a significant amount of energy transfer from Ce3+ ions to Eu2+ ions. By combining the title LaSrSiO3N:(Ce3+, Eu2+) phosphors with the 450 nm InGaN chip, a broad range of white light with correlated color temperatures of ~3500 K and color-rendering index of 92 can be generated, demonstrating their promising practical applicability to the warm-white light-emitting diodes.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
Inorganic Chemistry Frontiers
·
2020
·Vol. 7
·期 18
·3371-3378
·
IF 5.958
Yang Zhou,Xiaoming Wang,Cuiping Wang,Tian Zhang,Yonggang Wang,Fan Dou,Huan Jiao
A novel red fluoride phosphor BaNbF7:Mn4+ was synthesized via the conventional co-precipitation method. The structure and luminescence properties of BaNbF7:Mn4+ were investigated and discussed under various conditions. The BaNbF7:Mn4+ phosphor shows strong ZPL emission intensity at about 630 nm under ultraviolet (UV) and blue light excitation. It originated from the highly distorted Mn4+ octahedral coordination environment in the C3v group symmetry surrounding. A WLED fabricated with a blend of YAG:Ce3+ and the BaNbF7:Mn4+ phosphor exhibits a low color temperature (CCT = 3715 K) and a high color rendering index (Ra = 81.2), indicating its potential for application as a red phosphor for WLEDs.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Advanced Optical Materials
·
2026
·
IF 7.2
Zichen Zhao,Kai An,Jiefu Tan,Bo Hu,Kaihang Wang,Qianqian Wang,Feng Ding,Muzhi Cai,Desui Chen,Junjie Si,Zugang Liu
Metal halide perovskites are promising materials for next-generation light-emitting diodes (LEDs) owing to their excellent optoelectronic properties and low-cost solution processability. The efficiency and operational lifetime of perovskite LEDs (PeLEDs) are strongly governed by the crystal quality of perovskite emitters. Among the various factors influencing perovskite crystallization, the surrounding solvent vapors, particularly ambient moisture, can significantly modify both the initial-stage nucleation and the subsequent post-deposition structural evolution. However, current moisture treatments are highly engineering-driven, and the fundamental mechanisms underlying the impacts of moisture on perovskite remain unclear. This work systematically investigates how moisture treatment with controllable humidity modifies the structural and optoelectronic properties of CsPbBr 3 films. Moisture induces the rapid formation of Cs 4 PbBr 6 and promotes continuous crystal growth of CsPbBr 3 , resulting in alterations to the film composition, defect landscape, and grain-boundary characteristics that strongly affect carrier recombination and ion migration behaviors. Consequently, we achieve a champion device efficiency exceeding 20% after short-term moisture exposure, and a half-lifetime of 220 min at an initial luminance of 10 000 cd m −2 under prolonged moisture treatment. This work provides mechanistic insight into moisture-driven film evolution and demonstrates that the moisture treatment offers an effective strategy to enhance the performance of PeLEDs.
✓ 已验证
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2025
·
IF 3.5
Rui Zhu,Zelin Huang,Shengnan Zong
The thermal quenching effect of phosphors imposed significant limitations on the applications of luminescent materials in high-temperature environments, which can lead to device performance degradation or even system failure. Currently, there was a lack of red phosphors that demonstrate high luminous efficiency, excellent stability, and high color purity, making them suitable for white light-emitting diodes (LEDs). Herein, a strategy to enhance luminescence at elevated temperatures was achieved by synthesizing Eu 3+ -doped monoclinic NaScMo 2 O 8 phosphors, whose structural, morphological, thermal, and optical properties were characterized by XRD, SEM, TG, and PL spectroscopy. A comprehensive investigation of the optical properties revealed a significant increase in luminescence intensity with high Eu 3+ concentrations. At a doping concentration of 3 mol%, the phosphor exhibited the strongest electric dipole transition ( 5 D 0 - 7 F 2 ) with a maximum emission peak at 614 nm. Between 30 °C and 270 °C, the red characteristic emissions of Eu 3+ gradually intensified with rising temperature, reaching up to 8 times the intensity at room temperature, while maintaining consistent fluorescence characteristics. These findings highlighted its potential application in white LEDs.
研究领域:
材料科学
·
光学材料
·
固态照明
·
无机化学
·
发光
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2025
·
IF 19
Meiqin Xiao,Simin Gong,Jonghee Yang,Yi Wang,Junyu Nie,Wenzhe Li,Jiang Cheng,Hongkang Xu,Wei Zhang,Junzhong Wang,Ping Chen
Ion migration, especially taking place at the interface of perovskite/charge transport layer, poses great threats to the stability of perovskite light–emitting diodes (PeLEDs). However, the existing strategies mitigating ion migration sacrifice efficient charge injection, thus limiting the PeLED performances. Herein, an interfacial layer of a biaxially charge-polarized molecule, bi-4-(N-carbazolyl)phenyl)phenylphosphine oxide (BCPO), is applied. The strong surface coordination of BCPO not only manifests a high-quality metal halide perovskites (MHPs) emitter with improved defect passivation and crystallinity but also establishes a rigorous vertical dipole alignment, inducing band-bending for favorable electron injection. Additionally, the in-plane geometry of the electron-withdrawing carbazolylphenyl units achieves intimate lateral electrostatic contact with the MHPs surface, realizing stronger chemical interaction that suppresses the escape of halide at the interface. Encouraged by these achievements, the optimized PeLEDs with BCPO demonstrate maximum external quantum efficiency of 25.8% and T 50-EL lifetime of 13.4 h, representing one of the best green PeLEDs reported. This work newly opens a synergistic strategy, combined with molecular structure design and interfacial engineering, for simultaneously realizing efficient and color-stable PeLEDs, which tackles the crucial challenges for their commercialization.
研究领域:
材料科学
·
光电子学
·
纳米技术
·
分子工程
·
器件物理
✓ 已验证
产品关联
DOI
高影响因子
OPTICS AND LASER TECHNOLOGY
·
2020
·
IF 3.233
Xiaoyong Huang,Shaoying Wang,Balaji Devakumar
Red-emitting phosphors are highly demanded as color converters for both white light-emitting diodes (LEDs) and plant growth LEDs. Herein, we reported on the discovery of novel Mn 4+ ions doped Ca 2 YTaO 6 double-perovskite red-emitting phosphors. These samples were successfully prepared via the high-temperature solid-state reaction method, and their phase purity was confirmed by powder X-ray diffraction (XRD) patterns. XRD Rietveld refinement results revealed that the title compound crystallized in monoclinic space group P 2 1 / n with lattice parameters of a = 5.59630(8) Å, b = 5.82308(8) Å, c = 8.07158(12) Å, α = γ = 90 ° , β = 89.9768(23)°, and V = 263.034(4) Å 3 . The Ca 2 YTaO 6 structure consisted of abundant [TaO 6 ] octahedrons, providing appropriate sites for Mn 4+ incorporation. As obtained by photoluminescence measurements, the Ca 2 YTaO 6 :Mn 4+ phosphors showed a broadband excitation spectrum in the 250–600 nm wavelength range with two peaks around 350 and 514 nm. Under the 350 nm excitation, they exhibited narrowband deep-red emissions in the 630–750 nm wavelength range peaking at 680 nm with full-width at half maximum (FWHM) of 36 nm, corresponding to the spin-forbidden 2 E g → 4 A 2g transition of Mn 4+ ions. The investigation of the doping concentration-dependent optical properties of Ca 2 YTaO 6 :Mn 4+ phosphors indicated the critical quenching concentration equal to 0.2 mol%. The dipole-dipole interaction between Mn 4+ activators was the major mechanism leading to the concentration quenching effect. The fluorescence decay lifetimes of Ca 2 YTaO 6 :Mn 4+ phosphors decreased from 0.34 to 0.201 ms with increasing Mn 4+ doping concentrations. The CIE chromaticity coordinates of these phosphors were calculated based on the emission spectra, and the color purity reached up to 98.3%. Besides, the internal quantum efficiency of the optimal Ca 2 YTaO 6 :0.2%Mn 4+ sample was measured to be 21%.
研究领域:
材料科学
·
光学材料
·
固态化学
·
光子学
·
发光二极管（LED）
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）