DALTON TRANSACTIONS
·
2024
·Vol. 53
·期 9
·4325-4341
·
IF 3.5
P. J. Xia,X. Z. Zheng,L. Yue,Y. F. Lei,M. Xu,W. B. Dai
For further development of light sources, white light-emitting diodes (wLEDs) have attracted widespread attention as promising next-generation light sources fabricated via the combination of phosphors and LED chips. However, latent defects, such as chemical/thermal instability, low color rendering index (CRI) and high correlated color temperature (CCT), of current mainstream wLEDs seriously hinder their further large-scale implementation. Herein, in order to overcome these limitations, single-phase color-tunable gaudefroyite (Ca3Y(GaO)3(BO3)4 (CYGB)) tridoped with Bi3+/Tb3+/Eu3+ ions was synthesized for the first time and detailed characterisation was performed via high-temperature solid-state reaction and structural/spectral analyses, respectively. Radius difference percentage calculations and Rietveld refinements indicate that dopants occupy both Y3+ and Ca2+ sites but preferably the Y3+ site over the Ca2+ site due to the same valence state. Through subtly regulating the (co)doping contents and skillfully utilizing the energy transfer (ET) strategy from the allowed transition of blue light-emitting Bi to the forbidden transition of green/red light-emitting Tb/Eu, the color hue (including white light) of highly efficient PL can be easily tuned according to the need. Meanwhile, composition/content-optimized white light-emitting CYGB:2%Bi/10%Tb/12%Eu also shows splendid chemical/thermal stability. Finally, as a proof-of-concept experiment, the CYGB:2%Bi/10%Tb/12%Eu phosphor-converted wLED (pc-wLED) was fabricated and encapsulated via the up-to-date remote ‘capping’ method, which imparted attractive performances. Altogether, the stable CYGB:Bi/Tb/Eu phosphor is a promising candidate for application in lighting/display fields.
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
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2024
·
IF 3.8
Jiazhuang Guo,Pan Zhang,Liangliang Zhu,Hao Chen,Hai-Xia Shen,Cai-Feng Wang,Su Chen
Multicolor emissive carbon dots (CDs) have received increasing attention due to their excellent optical features. By far, insufficient studies have been conducted on the preparation and modulation of multicolor CDs, and most of the precursors used for the synthesis of multicolor CDs own benzene rings. Here, we report the solvent-engineered preparation of CDs with bright multicolor emissions. The CDs are fabricated by hydrothermal/solvothermal treatment of citric acid and cyanamide, circumventing the use of precursors containing aromatic molecules as well as the medium of concentrated acids. By simply changing the reaction solvent, the emission wavelength of the CDs shifts from the blue to yellow region, and even white emissive CDs are obtained. Specifically, blue, cyan, yellow, and white emissive CDs are obtained to exhibit photoluminescence quantum yields (PL QYs) ranging from 19.7% to 62.3%. Further studies show that the bright fluorescence might originate from molecular fluorophore grafting on the CD surface. Moreover, CDs/polymer composites with uniform bright luminescence are prepared and used as fluorescent color-converting materials for fabricating multicolor LEDs. This study extends the modulated preparation of multicolor emissive CDs that are potentially useful for optoelectronic applications.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHARACTERIZATION
·
2025
·
IF 5.5
Yanqing Zu,Tong Zhang,Binglin Zeng,Decui Gong,Chengzhang Yang,Chujie Wang,Run Gan,Lixia Jing,Peitao Liu,Xiaodong Li,Lei Zhao,Ailing Feng,Zhaoxin Wu
Perovskite nanocrystals (NCs) have attracted much attention in the fields of laser, color conversion and X-ray imaging. However, the poor photophysical properties and stability of NCs due to the proton exchange of traditional X-type ligands such as the pair of oleic acid and oleylamine as well as their easy detachment after purification or long-time storage, have become the major bottleneck for practical applications. Herein, we exploit an in-situ passivation strategy for CsPbBr 3 NCs by merely using a L-type bidentate ligand, namely 1,3-bis(3-aminopropyl) tetramethyldisiloxane (BAPTRDS). Theoretical calculations indicate that this double bridging of BAPTRDS on the surface of NCs can achieve a much larger binding energy (−1.86 eV) in comparision to single chelated 3-aminopropyl-triethoxysilane (APTES) (−1.05 eV). The BAPTRDS passivated NCs exhibit a high photoluminescence quantum yield of 71 %. Besides, the X-ray imaging detector and white light-emitting diodes (WLEDs) were separately obtained by BAPTRDS capped NCs, both of which possess the impressive performance. This work not only can provide deep understanding for surface chemistry of perovskite NCs, but also acquire high-quality CsPbBr 3 NCs for dual applications in X-ray imaging and display.
研究领域:
材料科学
·
光学工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
You Zhang,Kun Zhao,Haoyu Zhu,Qiong Xi,Nian Fu,Dawei Wang,Jinxing Zhao,Li Guan,Yunfei Zhuang,Xu Li
White light-emitting diodes (WLEDs) have emerged as a leading technology for healthy lighting and advanced displays. Nevertheless, the poor thermal stability of blue-emitting components remains a significant bottleneck, hindering their broader adoption in demanding environments. Here, we have prepared a series of Ca 3 Al 2 O 6 :Ce 3+ phosphors by high temperature solid-state method. Substituting the [Al 3+ –O 2- ] ionic pair with [Si 4+ –N 3- ] in the Ca 3 Al 2 O 6 host lattice via a charge-compensated strategy achieves a 1.75 times enhancement in thermal stability compared to the pristine material, while simultaneously inducing a blue-shifted emission spectrum (Δλ = 30 nm). The enhanced thermal stability originates from increased lattice rigidity, while the blue spectral shift arises from modulated crystal field splitting decrease. These mechanistic insights provide a foundational strategy for designing ultra-stable blue phosphors compatible with high-power WLED applications.
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
Materials
·
2025
·Vol. 18
·期 9
·1896
·
IF 3.2
Yanbiao Li,Yuefeng Gao
Stable and efficient inorganic lead-free double perovskites are crucial for high-reliability optoelectronic devices. However, dual-doped perovskite phosphors often suffer from poor color stability due to differences in thermal activation energies and electron–phonon interactions between the doped ions. To address this, single-doped Sb3+-incorporated Rb2HfCl6perovskite crystals were synthesized via a co-precipitation method. Under UV excitation, Rb2HfCl6:Sb exhibits broad dual emission bands, attributed to singlet and triplet self-trapped exciton radiative transitions induced by Jahn–Teller distortion in [SbCl6]3−octahedra. This dual emission endows the material with high sensitivity to excitation wavelengths, enabling tunable luminescence from cyan to orange-red across 400–800 nm. Utilizing this dual emission, a white LED was fabricated, showcasing a high color rendering index and excellent long-term stability. Remarkably, the material exhibits breakthrough thermal stability, maintaining more than 90% of its emission intensity at 100 °C, while also exhibiting remarkable resistance to humidity and oxygen exposure. Compared to co-doped phosphors, Rb2HfCl6:Sb offers advantages such as environmental friendliness, simple fabrication, and stable performance, making it an ideal candidate for WLEDs. This study demonstrates notable progress in developing thermally stable and reliable optoelectronic devices.
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
INORGANIC CHEMISTRY
·
2024
·
IF 4.3
Shaokun Ling,Yaxiong Wang,Xiaoyan Qin,Chang Chen,Chunchun Lu,Jidong Chen,Sen Liao,Yingheng Huang,Lei Hou
Although being applied in various fields, white light emitting diodes (WLEDs) still have drawbacks that urgently need to be conquered: the luminescent intensity of commercial phosphors sharply decreases at working temperature. In this study, we calculated the forming energy of defects and confirmed that the VNa defect state can stably exist in β-NaGdF4, by density functional theory (DFT) calculation. Furthermore, we predicted that the VNa vacancies would provide a zero thermal quenching (ZTQ) property for the β-NaGdF4-based red-light phosphor. Then, a series of β-NaGdF4:xEu3+ and β-NaGdF4:0.25Eu3+,yYb3+ red-light phosphors were synthesized by the hydrothermal method. We found that β-NaGdF4:0.25Eu3+ and β-NaGdF4:0.25Eu3+,0.005Yb3+ phosphors possess ZTQ properties at a temperature range between 303–483 K and 303–523 K, respectively. The thermoluminescence (TL) spectra were employed to calculate the depth and density of the VNa vacancies in β-NaGdF4:0.25Eu3+ and β-NaGdF4:0.25Eu3+,0.005Yb3+. Combining the DFT calculation with characterization results of TL spectra, it is concluded that electrons stored in VNa vacancies are excited to the exited state of Eu3+ to compensate for the loss of Eu3+ luminescent intensity. This will lead to an increase of luminescent intensity at high temperatures and facilitate the samples to improve ZTQ properties. WLEDs were obtained with CRI = 83.0, 81.6 and CCT = 5393, 5149 K, respectively, when phosphors of β-NaGdF4:0.25Eu3+ and β-NaGdF4:0.25Eu3+,0.005Yb3+ were utilized as the red-light source. These results indicate that these two phosphors may become reliable red-light sources with high antithermal quenching properties for WLEDs.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
PubMed
高影响因子
DALTON TRANSACTIONS
·
2017
·Vol. 46
·期 40
·13835-13844
·
IF 4.029
Luqing Xi,Yuexiao Pan,Mengmeng Zhu,Hongzhou Lian,Jun Lin
A novel red phosphor, NaHF2:Mn4+ (NHF:Mn), was obtained via substituting Na+ located at the center of the octahedron coordinated with six F− ions with Mn4+ in the host lattice of NHF. The phase purity and the exact composition of the obtained NHF:Mn were confirmed by X-ray powder diffraction (XRD), Rietveld refinement, energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and infrared (IR) spectroscopy, respectively. The luminescence intensity of NHF:Mn was enhanced by optimizing the synthetic conditions. A series of warm white light-emitting diodes (WLEDs) with a color rendering index (CRI) higher than 88.0 and correlated color temperatures (CCT) between 3146 and 5172 K were obtained by encapsulating the as-prepared red phosphor NHF:Mn with the yellow one Y3Al5O12:Ce3+ (YAG:Ce) on blue chips. The advantage of the synthetic strategy to obtain NHF:Mn can be extended to develop novel Mn4+ doped red phosphors via substituting for central ions with unequal electric charge in the centers of octahedra.
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 THE AMERICAN CERAMIC SOCIETY
·
2025
·
IF 3.8
Peng Ren,Fayan Feng,Li Gao,Ming Cheng,Xianggui Li,Qiang Zhou,Huaijun Tang,Zhengliang Wang
Mn 4+ -doped fluoride phosphors have attracted extensive attention in the white light-emitting diode (LED) field due to their efficient red emission, whereas significant luminescence thermal quenching restricts their development. Herein, we propose to improve the luminescence thermal stability of A 2 GeF 6 :Mn 4+ ( A = Rb + and K + ) by a translucent ceramic fabrication strategy. For the Rb 2 GeF 6 lattice, a phase transition from the P 6 3 mc space group to the P 3 ¯ $\bar 3$ m 1 space group occurs as the material transforms from powder to translucent ceramic, resulting in the disappearance of the zero-phonon line (ZPL) emission of Mn 4+ ions. During the translucent ceramic fabrication process, no phase transition is observed in the K 2 GeF 6 host. Notably, the PL thermal stability of the fluoride phosphors can be improved by the translucent ceramic fabrication strategy applied to both systems, with or without phase transitions. The LED-ceramic device also exhibits better performance than the LED-powder. After 40 min of high-power operation, the temperature of LED-ceramic rose six times less than that of LED-powder, demonstrating superior thermal stability. These results highlight the efficacy of the translucent ceramic strategy in enhancing the performance and stability of LEDs.
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
Light-Science & Applications
·
2025
·Vol. 14
·期 1
·1-10
·
IF 23.4
Li Haotao,Wang Jiming,Chen Shuming
The realization of solution-processed tandem quantum-dot LEDs (QLEDs) remains a technical challenge due to the limitations of inefficient interconnect layer and the damage caused by multiple solution processes. Here, we develop a high performance tandem QLED by face-to-face integrating a top-emitting QLED with a transparent QLED. The top and bottom units can be addressed independently, thereby enabling the tandem QLED to operate in series, parallel, and color-tunable modes for multifunctionality. In series mode, QLEDs demonstrate an ultra-low turn-on voltage of 3.3 V and a record-breaking external quantum efficiency of 60.7%. In parallel mode, QLEDs achieve an impressive brightness of over 4.8 × 10 6 cd m -2 . In color-tunable mode, the color, brightness, and color temperature can all be adjusted with a color tuning range of 114% NSTC. Moreover, both series and parallel connections contribute to an improved stability, resulting in a T 95 lifetime of nearly 30,000 h at 1000 cd m -2 , which is an improvement of approximately 2.8 times over control devices. Our work offers a feasible solution for achieving multifunctional tandem QLEDs with the advantages of solution processed, high efficiency, high brightness, long lifetime and full color tunability for various light source applications.
研究领域:
材料科学
·
光电技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2025
·
IF 3.5
Shao-rong Bie,Ding-shun She,Wen Yue
A series of Ca 10 (PO 4 ) 6 F 2 :Er 3+ phosphors doped with varying concentrations of Er 3+ concentrations (2–14 mol.%) have been synthesized via a hydrothermal method to investigate their optical spectroscopy and temperature-sensing properties. Rietveld refinements of the XRD data reveal that Er 3+ ions preferentially occupy Ca2 sites rather than Ca1 sites to reduce electrostatic repulsion between cations within the fluorapatite lattice. Morphological characterization using SEM, TEM, and EDS confirms that the synthesized phosphors exhibit a rod-like morphology with dimensions of approximately 2.5 μm in length and 1 μm in diameter, along with an excellent single-crystal structure and uniform elemental distribution. Under 378 nm excitation, the phosphors exhibit prominent green emission peaks corresponding to the 2 H 11/2 → 4 I 15/2 and 4 S 3/2 → 4 I 15/2 transitions of Er 3+ ions. The optimal dopant concentration is determined to be 10 mol.%, with a calculated critical distance of 9.98 Å, indicating that electric quadrupole–quadrupole interactions dominate the concentration quenching mechanism. The luminescence lifetime of the optimized phosphor has been measured as 0.604 ms. Additionally, the chromaticity coordinates (0.3127, 0.6723) and high color purity (98.06 %) highlight the potential applicability of this phosphor in white light-emitting diodes (LEDs) and other optoelectronic devices.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
ACS Materials Au
·
2022
·
IF 0
Shunqi Lai,Ming Zhao,Yifei Zhao,Maxim S. Molokeev,Zhiguo Xia
Regulation of Eu2+ dopants in different cation sites of solid-state materials is of great significance for designing multicolor phosphors for light-emitting diodes (LEDs). Herein, we report the selective occupation of Eu2+ for multiple cationic sites in KSrScSi2O7, and the tunable photoluminescence from blue to cyan is realized through Eu2+ doping concentration-dependent crystal-site engineering. Eu2+ preferably occupies the K and Sr sites in KSrScSi2O7 at a low doping concentration, resulting in a 440 nm blue emission. As the Eu2+ concentration increases, a new Eu2+ substitution pathway is triggered, that is, Eu2+ enters the Sc site, leading to the red-shifted emission spectra from 440 to 485 nm. The doping mechanism and photoluminescence properties are corroborated by structural analysis, optical spectroscopy study, and density functional theory calculations. The optical properties of the as-fabricated white LEDs are studied, which demonstrates that these phosphors can be applied to full-spectrum phosphor-converted LEDs. This study provides a new design strategy to guide the development of multicolor Eu2+-doped oxide phosphors for lighting applications.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
Nanomaterials
·
2022
·Vol. 12
·期 24
·4397
·
IF 5.719
Yongqiang Zhong,Qian Wu,Jiujun Zhu,Peiqing Cai,Peng Du
Luminescent materials with high thermal stability and quantum efficiency are extensively desired for indoor illumination. In this research, a series of Eu3+-activated KGd2F7red-emitting nanoparticles were prepared at room temperature and their phase structure, morphology, luminescence properties, as well as thermal stability, have been studied in detail. Excited by 393 nm, the resultant nanoparticles emitted bright red emissions and its optimal status was realized when the Eu3+content was 30 mol%, in which the concentration quenching mechanism was triggered by electric dipole–dipole interaction. Through theoretical analysis via the Judd–Ofelt theory, one knows that Eu3+situates at the high symmetry sites in as-prepared nanoparticles. Moreover, the internal and extra quantum efficiencies of designed nanoparticles were dependent on Eu3+content. Furthermore, the studied nanoparticles also had splendid thermal stability and the corresponding activation energy was 0.18 eV. Additionally, via employing the designed nanoparticles as red-emitting constituents, a warm white light-emitting diode (white-LED), which exhibits low correlated color temperature (4456 K), proper luminous efficiency (17.2 lm/W) and high color rendering index (88.3), was developed. Our findings illustrate that Eu3+-activated KGd2F7nanoparticles with bright red emissions are able to be used to promote the performance of white-LED.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）