Journal of Materials Chemistry C
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2023
·Vol. 11
·期 27
·9281-9290
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IF 6.4
Sixiang Wang,Yichang Wang,DaeHo Yoon,Tianrong Li,Yuhua Wang
Green light conversion materials with small particle sizes and high luminous quality are essential for high-resolution display technology, such as Mini-LEDs and Micro-LEDs. Here, we demonstrate an effective strategy to prepare a sub-micrometer green phosphor via doping Mn2+ in a small-sized organic–inorganic hybrid Zn(II) bromide (C8H20N)2ZnBr4. Among a series of prepared (C8H20N)2Zn1−xMnxBr4 (x = 0–1.0), (C8H20N)2Zn0.7Mn0.3Br4 showed a particle size of around 700 nm, an emission peak centered at 517 nm with a full width at half maximum of 47 nm, a photoluminescence quantum yield of about 80%, and a stabilized photoluminescence intensity with a slight increase under continuous UV-light illumination over a 30 day test range. A [MnBr4]2− tetrahedron was effectively split by a massive tetraethylammonium cation (C8H20N)+ and [ZnBr4]2− tetrahedron unit in the zero-dimension structure, which was considered responsible for reducing the electron–phonon coupling of Mn2+, accelerating the leap process of [MnBr4]2−, and enhancing the optical and thermal stability of emitting centers. These results indicated that (C8H20N)2Zn0.7Mn0.3Br4 is a valuable candidate for Mini-LEDs and Micro-LEDs.
研究领域:
材料科学
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光电技术
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显示技术
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DOI
高影响因子
JOURNAL OF MATERIALS CHEMISTRY
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2012
·Vol. 22
·期 31
·15887-15893
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IF 5.968
Hongde Luo,Jie Liu,Xiao Zheng,Lixian Han,Kuaixia Ren,Xibin Yu
Trivalent ions B3+, Al3+ and Ga3+ have been introduced into Sr3SiO5:Ce3+ in this study. Among these ions, Al3+ and Ga3+ act as charge compensators and significantly enhance the maximum emission of Ce3+ by about 100% and 90%, respectively. Then, Al3+, Eu2+ co-doped Sr3SiO5:Ce3+ phosphors have been researched, which indicate that the emission spectra can be tuned from 530 to 575 nm by changing the concentration of Eu2+. The CIE chromaticity coordinates of the phosphors were calculated from (0.342, 0.518) to (0.442, 0.479). This indicates a potential for applications in daylight LEDs or warm-white LEDs.
研究领域:
材料科学
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光学
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DOI
高影响因子
JOURNAL OF LUMINESCENCE
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2022
·
IF 4.171
Jiyao Xu,Yuman Zhang,Xiangjun Guo,Hongmei Zhang,Yujia Deng,Xihui Zhao
At present, most of the reported carbon dots (CDs) are still dispersed in the solvent in liquid state . However, solid-state CDs cannot fundamentally prevent the aggregation-caused quenching effect (ACQ), which seriously affects their application. Herein, hydrophobic solid-state luminescent CDs with typical aggregation-induced emission (AIE) behavior were synthesized by simple solvothermal method using dithiosalicylic acid (DSTA) and acetic acid. The AIE behavior of CDs is mainly due to the presence of disulfide bonds, which restrict the intramolecular rotation of CDs surface groups around them, thus generating solid-state fluorescence (SSF) in long-wave emission. In addition, by using MA , urea and sulfonamide to tune the emission behavior of CDs, red, yellow and green AIE CDs named R-CDs, Y-CDs and G-CDs were obtained successfully. The as-prepared CDs powder was further applied to fabricate multi-color light-emitting diodes (LEDs) on UV chips. The fabricated tri-color LED devices can maintain high color purity and color rendering index (CRI). More importantly, the Correlated color temperature (CCT) of the three LED devices was located in the warm light area, which could effectively reduce visual fatigue. Finally, we applied three kinds of AIE CDs in fingerprint detection and effectively displayed the details.
研究领域:
材料科学
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光学
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应用化学
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DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
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2023
·Vol. 106
·期 8
·4818-4830
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IF 3.9
Qianwen Cao,Liang Li,Jing Xie,Yuan Feng,Wenming Wang,Yan Pan,Xiantao Wei,Yong Li
Phosphors doped with Mn 4+ ions have strong emission in the red and far-red light regions and are therefore used as red phosphors for indoor plant cultivation light-emitting diodes (LEDs) and white LEDs (w-LEDs). This paper introduces La 2 Mg(Mg 1/3 Ta 2/3 )O 6 : Mn 4+ (Mg 2 La 3 TaO 9 : Mn 4+ ) red phosphors prepared by conventional high-temperature solid-phase method. The broad excitation band of Mg 2 La 3 TaO 9 : Mn 4+ phosphor is effectively excited by ultraviolet and blue light in the range of 250–600 nm, with the emission of 707 nm centered on far-red light. The phosphor has a high color purity of 99.07% and an internal quantum efficiency of 59.87%. To further enhance the performance of the phosphor, a cation substitution method was adopted in this paper to synthesize La 2 Mg(Al 1/2 Ta 1/2 )O 6 : Mn 4+ phosphor by replacing [1/3Mg 2+ –2/3Ta 5+ ] in La 2 Mg(Mg 1/3 Ta 2/3 )O 6 : Mn 4+ with [1/2Al 3+ –1/2Ta 5+ ]. The luminescence intensity and thermal stability of the samples were enhanced. The emission spectrum of the Mg 2 La 3 TaO 9 : Mn 4+ samples matched well with the phytochrome P FR (phytochrome that absorbs far-red light) and is suitable for the preparation of LEDs for indoor plant cultivation. The concentration quenching effect of the samples was investigated, the main mechanism of which is the electric dipole–dipole interaction. Red LEDs and w-LEDs devices were prepared with the synthesized phosphors that produce light stably at different currents. The w-LEDs have a correlated color temperature of 5310 K and a color rendering index of 80.1. Therefore, these samples are expected to be used as red components for w-LEDs.
研究领域:
材料科学
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光学工程
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植物栽培技术
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DOI
高影响因子
AICHE JOURNAL
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2019
·Vol. 66
·期 2
·e16841
·
IF 3.463
Chong Shen,Minjing Shang,Hong Zhang,Yuanhai Su
In this work, we report a simple and inexpensive UV-LEDs based photomicroreactor assembly constructed by commercially available components. The photoisomerization of norbornadiene to quadricyclane was selected to validate this novel photomicroreactor design. Mass transport limitation was eliminated and indicated by dimensionless numbers Fo and Da II , and photons loss was evaluated considering the absorption and reflection of the microreactor walls. The solvents, photosensitizers, and light sources selections were optimized for achieving better photochemical performance and mechanistic insights. The detailed comparison between the high-pressure mercury arc lamp and the UV-LEDs strip revealed great potential of UV-LEDs as appealing light source for photochemical transformations. Moreover, the reaction mechanism was thoroughly discussed and illustrated by the Jablonski diagram indicating electronic states transitions. According to possible intermediate steps, a kinetic model was proposed with the reaction rate constant being correlated with the photon flux, which is valuable for process optimization and further understanding reaction mechanisms.
研究领域:
化学工程
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光化学
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反应动力学
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DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2020
·
IF 4.65
Changyan Ji,Zhi Huang,Xiuying Tian,Hengping He,Jin Wen,Yangxi Peng
A series of red emitting phosphors Mg 3 Y 2-x Ge 3 O 12 :xSm 3+ (0≤x ≤ 0.06) were successfully synthesized. Samples Mg 3 Y 2-x Ge 3 O 12 :Sm 3+ exhibited a cubic structure pertaining to the I a-3d (230) space group and the particle sizes range from 1 μm to 5 μm. The optical properties displayed that the optimum doping concentration of Sm 3+ is 4%. The phosphor Mg 3 Y 1.96 Ge 3 O 12 :0.04Sm 3+ not only exhibited a broad band gap of 5.54 eV but also showed a high color purity of 97.6%. In addition, the strongest emission intensity located at 566 nm belonged to the 4 G 5/2 → 6 H 5/2 transition when excited at 405 nm. Thermal quenching test revealed that the sample Mg 3 Y 1.96 Ge 3 O 12 :0.04Sm 3+ are excellent powders with splendid thermal stability, in which only 3.6% of the PL intensity is quenched at 473 K in comparison with that of 298 K. As a result, the W-LEDs based on Mg 3 Y 1.96 Ge 3 O 12 :0.04Sm 3+ yielded a high R a of 91.1, a low CCT of 4881 K, and CIE coordinates of (0.3476, 0.3466) in a 20 mA driven current. This research work provided important guidance for the synthesis of Sm 3+ doped red component with excellent luminesce properties and high thermal stability characteristics used in W-LEDs.
研究领域:
材料科学
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光学工程
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高影响因子
NEW JOURNAL OF CHEMISTRY
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2020
·Vol. 45
·期 1
·66-75
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IF 3.288
Pengfei Zhang,Na Li,Zhiting Wei,Ziqi Wang,Mengwei Gou,Lei Zhao,Wenbo Chen,Qinping Qiang
Alternating current light-emitting diodes (AC-LEDs) set up a new era of economic semiconductor-based lighting. However, the flicker of AC-LEDs in the AC cycles is unhealthy for human eyes. In this work, the red-emitting afterglow phosphor Ca4Nb2O9:Pr3+ was successfully synthesized via a traditional high temperature solid-state reaction method. The phase composition, photoluminescence spectra, afterglow curve, and thermoluminescence were investigated. It was revealed that the red emission (617 nm) is ascribed to the 3P0 → 3H6 transition of Pr3+ ions, and the afterglow time was in the second range after removal of the excitation source. In order to gain a deeper understanding of the origin of afterglow, a subsequent thermoluminescence analysis was performed and a relatively shallow trap within the host was found. These results indicated that Ca4Nb2O9:Pr3+ phosphors could compensate for the flickering behavior of AC-LEDs and may be a candidate for application in AC-LEDs.
研究领域:
材料科学
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光电
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光子学
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高影响因子
Light-Science & Applications
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2023
·Vol. 12
·期 1
·1-9
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IF 19.4
Lu Po,Li Ting,Lu Min,Ruan Cheng,Sun Siqi,Wu Zhennan,Zhong Yuan,Zhang Fujun,Gao Yanbo,Huang Yaowei,Wang Yang,Hu Junhua,Yan Fengping,Zhang Yu
Considering the multi-functionalization of ligands, it is crucial for ligand molecular design to reveal the landscape of anchoring sites. Here, a typical triphenylphosphine (TPP) ligand was employed to explore its effect on the surface of CsPbI 3 perovskite nanocrystals (PNCs). Except for the conventionally considered P-Pb coordination, an P-I supramolecular halogen bonding was also found on the NC surface. The coexistence of the above two types of bonding significantly increased the formation energy of iodine vacancy defects and improved the photoluminescence quantum yield of PNCs up to 93%. Meanwhile, the direct interaction of P and I enhanced the stability of the Pb-I octahedra and dramatically inhibited the migration of I ions. Furthermore, the introduction of additional benzene rings (2-(Diphenylphosphino)-biphenyl (DPB)) increased the delocalized properties of the PNC surface and significantly improved the charge transport of the PNCs. As a result, the DPB passivated CsPbI 3 NCs based top-emitting LEDs exhibite a peak external quantum efficiency (EQE) of 22.8%, a maximum luminance of 15, 204 cd m −2 , and an extremely low-efficiency roll-off of 2.6% at the current density of 500 mA cm −2 .
研究领域:
材料科学
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纳米技术
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光电
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DOI
PubMed
高影响因子
JOURNAL OF LUMINESCENCE
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2020
·
IF 3.28
Wei Li,Nan Ma,Qi Sun,Shaoying Wang,Zongjie Zhang,Balaji Devakumar,Xiaoyong Huang
Novel efficient Ba 2 YTaO 6 :Mn 4+ (BYT:Mn 4+ ) far-red emitting double-perovskite phosphors for plant cultivation LEDs were reported in this article. These phosphors were successfully synthesized via a traditional high-temperature solid-state reaction method, and their crystal structure, luminescence properties, fluorescence decay lifetimes, Commission Internationale de l'Eclairage (CIE) chromaticity coordinates, internal quantum efficiency, and thermal stability have been systematically investigated. XRD Rietveld refinement demonstrated that the BYT:Mn 4+ compound crystallized into cubic crystal system with Fm 3 ‾ m space group, and the lattice parameter were a = b = c = 8.445 (7) Å, α = β = γ = 90°, and V = 602.231 (10) Å 3 . Interestingly, the obtained samples showed an intense far-red emission band centered at 690 nm under excitation of 360 nm, which matched well with the absorption band of phytochrome P FR. In BYT:Mn 4+ phosphors, the Mn 4+ ions occupied the TaO 6 octahedron by replacing the Ta 5+ site, and the optimal doping concentration of Mn 4+ ions was determined to be 0.4 mol%. The CIE chromaticity coordinates and internal quantum efficiency of BYT:0.4%Mn 4+ phosphors were (0.7283, 0.2717) and 41.5%, respectively. In addition, when the temperature reached at 423 K, the emission intensity of BYT:0.4%Mn 4+ phosphors remained 37% of that at 303 K. Therefore, all of these investigations demonstrated that BYT:Mn 4+ phosphors could be used as potential far-red emitting phosphors for plants cultivation LEDs.
研究领域:
材料科学
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植物生物学
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光电技术
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DOI
高影响因子
CHEMISTRY OF MATERIALS
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2024
·
IF 7.2
Zurong Liao,Małgorzata Sójka,Jiyou Zhong,Jakoah Brgoch
Materials emitting near-infrared (NIR) light play a crucial role in the development of phosphor-converted light-emitting diodes (pc-LEDs) for applications ranging from fundamental science like spectroscopic analysis to highly applied uses like night vision and biological imaging. One class of materials that has garnered significant interest for these technical spaces is Cr3+-activated garnets due to their high efficiency and ability to operate at relatively high temperatures. However, their limited emission beyond 800 nm impedes their use as optimal blue LED-pumped NIR-emitting materials. In this study, we present a new garnet-type NIR phosphor, Na2CaZr2Ge3O12:Cr3+, that addresses this challenge─the material exhibits a long-wavelength emission (λem,max = 832 nm) and good thermal quenching resistance while maintaining an excellent internal quantum efficiency (IQE = 98%). These properties are attributed to a crystal environment reconstruction, where a crystal structure distortion is coupled to a weak crystal field, which is uncommon for most rigid garnet-type phosphors. Furthermore, the fabricated NIR pc-LED devices using this material demonstrate superior performance compared with devices employing well-known efficient NIR phosphors operating in this emission range. The light source is subsequently demonstrated in applications spanning night vision, bioimaging, and nondestructive analysis. This study not only provides insights into the luminescence properties of Cr3+-activated garnet materials with desirable performance but also highlights the practical application of NIR-emitting garnet phosphors.
研究领域:
材料科学
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光子学
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光电技术
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生物医学工程
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DOI
高影响因子
Micromachines
·
2023
·Vol. 14
·期 3
·566
·
IF 3.4
Wenjun Huang,Xiangyu Miao,Zhaojun Liu
The optoelectronic effects of sidewall passivation on micro-light-emitting diodes (Micro-LEDs) were investigated using sol-gel chemical synthesis. Blue InGaN/GaN multi-quantum well (MQW) Micro-LEDs, ranging in size from 20 × 20 μm to 100 × 100 μm and with high EQE, were fabricated and distinguished by the passivation method used, including no passivation, sol-gel SiO2, and plasma-enhanced chemical vapor deposition (PECVD) SiO2. Impressively, the sol-gel method is advantageous in improving the optoelectronic performance of Micro-LEDs. The fabricated 20 × 20 μm Micro-LEDs showed an EQE of 27.7% with sol-gel passivation, which was a 14% improvement compared to devices without sidewall passivation. Sol-gel sidewall passivation allows Micro-LEDs to effectively achieve sharper edge emission, superior surface luminous uniformity, and intensity, providing the possibility for the fabrication of low-cost and high-efficiency Micro-LEDs.Keywords:sidewall passivation;sol-gel SiO2;GaN-based micro-light-emitting diodes (Micro-LEDs)
研究领域:
材料科学
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光电子学
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半导体器件
✓ 已验证
DOI
PubMed
高影响因子
Materials Today Energy
·
2024
·
IF 9
Haochen Liu,Xiangtian Xiao,Ye Wu,Ding Zhu,Jiayun Sun,Desui Chen,Bing Tang,Shixun Wang,Arsenii Portniagin,Kunnathodi Vighnesh,Wallace C.H. Choy,Andrey L. Rogach
Pure-red emission light-emitting diodes (LEDs) are highly desirable for display and lighting applications. Here, we present a synergistic approach to fabricate pure-red emission LEDs based on quantum-confined CsPbI 3 nanocrystals (NCs). By introducing ZnI 2 acting as a co-precursor and passivating agent into the synthesis, and applying a gradient post-synthesis purification method allowing us to obtain size-selected fractions with precisely adjusted emission colors, we obtained uniform and small (about 6 nm), quantum-confined CsPbI 3 NCs exhibiting high stability in ambient conditions and a superior photoluminescence quantum yield of up to 88%. These NCs exhibited the tendency to undergo oriented attachment, resulting in self-assembled superstructures with a pure-red emission at 629 nm. Importantly, partial recrystallization into fused superstructures led to removal of the insulating ligand barriers between NCs. LEDs based on the CsPbI 3 NCs showed pure-red electroluminescence at 633 nm, with an external quantum efficiency of 14.7% and a luminance of over 1000 cd/m 2 . Our study reveals the mechanism behind the oriented attachment and assembly of small, quantum-confined CsPbI 3 NCs, and contributes to the development of pure-red electroluminescent LEDs.
研究领域:
材料科学
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光电技术
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纳米科技
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）