AICHE JOURNAL
·
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
·
光化学
·
反应动力学
✓ 已验证
DOI
高影响因子
ACS Applied Polymer Materials
·
2025
·
IF 4.7
Xiangzhuo Han,Yingchao Zhang,Jinkai Wang,Zhanchen Cui,Zuosen Shi
Sulfonate oxime ester photoinitiators (PIs) based on a thioether-substituted 1,8-naphthalenedicarboximide backbone exhibit good absorption at the emission wavelengths of commonly used LED lamps (385, 395, and 405 nm). The presence of weak C–S and N–O bonds in the molecular structure enables them to be cleaved under light, which leads to the generation of free radicals and cations with efficient initiation properties. Electron paramagnetic resonance spectroscopy supports the mechanism of C–S bond cleavage to produce free radicals, and UV–visible real-time spectroscopy in the presence of Rhodamine B base supports the mechanism of N–O bond cleavage to produce acids. These compounds are high-performance photoinitiators without any other additives for the polymerization of double-bonded compounds and epoxides. They can be initiated at low concentrations when exposed to UV-LEDs. These photoinitiators provide important ideas for the design and synthesis of photoinitiators, which have great potential for application in the field of photopolymerization, especially in hybrid light-curing systems.
研究领域:
材料科学
·
光化学
·
聚合物科学
✓ 已验证
产品关联
DOI
高影响因子
INORGANIC CHEMISTRY
·
2023
·
IF 4.6
Huimin Li,Ran Pang,Lihong Jiang,Da Li,Su Zhang,Hongjie Zhang
Current ultraviolet (UV) light sources are dominated by blacklights that contain mercury vapor. Improper disposal or accidental breakage of these lamps can lead to serious pollution. Phosphor-converted light-emitting diodes (pc-UV-LEDs) have the potential to replace these mercury-containing lamps, making them more environmentally friendly. To improve the adjustability of the UV emission and reduce production cost, a series of UV-emitting phosphors were developed by introducing Bi3+ in BaSc2Ge3O10 (BSGO) which has a broad bandgap of 5.88 eV. The phosphor exhibits a negative thermal quenching effect that results from thermally activated defects. Despite this, the emission intensity of the phosphor sustains up to 107% at 353 K and 93% at 473 K compared to the intensity at 298 K. The internal quantum efficiency and the external quantum efficiency reach 81.0 and 49.32%, respectively, under 305 nm excitation. A pc-UV-LEDs were fabricated by combining the phosphor with a chip. The resulting device emits a broad band ranging from 295 nm to 450 nm, covering part of the UVB (280 nm ∼ 315 nm) and UVA (315–400 nm) regions. Our work has the potential to promote the replacement of current blacklights, including high-pressure mercury lamps and fluorescent low-pressure mercury lamps, by pc-UV-LEDs in applications such as bug zappers and tanning beds. Moreover, the phosphor exhibits desirable long persistent luminescence, which extends its prospect of applications.
研究领域:
材料科学
·
光子学
·
固态照明
·
发光材料
·
光电子学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Ying Lv,Siting Fan,Yujie Zhao,Yu Liu,Xiaohang Zhang,Jie Zhao,Jian Yu
Single-component white phosphor is highly desirable to obtain efficient and stable white light-emitting diodes (w-LED). In this paper, a series of Bi 3+ , Tb 3+ , and Eu 3+ doped Ca 3 LuAl 3 B 4 O 15 (CLAB) luminescent materials were successfully prepared. The structure, morphology, and optical properties of samples were characterized by X-ray diffractometer, scanning electronic microscopy, and fluorescence spectroscopy , respectively. The synthesized phosphor exhibits strong blue band emission from Bi 3+ and intense characteristics line emission from Tb 3+ and Eu 3+ under ultraviolet (UV) light excitation. The emission color can fine be adjusted by changing the doping content of the three activators. The warm white light of CLAB:0.5%Bi 3+ ,2%Tb 3+ ,0.75%Eu 3+ with CIE chromaticity coordinates of (0.3728,0.3166), a CCT of 3671 K, and a Ra index of 87 could be realized under UV light excitation. The fabricated w-LED by combining UV chip with CLAB:0.5%Bi 3+ ,2%Tb 3+ ,0.75%Eu 3+ shows excellent thermal stability after high-temperature aging test, implying its promising application in single-phosphor-converted warm w-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
Journal of Materials Chemistry C
·
2016
·Vol. 4
·期 13
·2506-2512
·
IF 5.066
X. Y. Liu,H. Guo,Y. Liu,S. Ye,M. Y. Peng,Q. Y. Zhang
The design of white-light luminescent materials with excellent thermal stability is still a challenge in the field of white-light emitting diode (W-LED) application. In this paper, a pair of novel Bi3+/Mn2+ ions co-doped into white-emitting borosilicate glasses were successfully prepared using a melt-quenching method. Their luminescence properties were evaluated using transmission spectra, photoluminescence excitation and emission spectra in the temperature range of 300–573 K, and lifetime decay curves. Upon excitation with a ultraviolet (UV) light, the co-doped glasses exhibit intense tunable emitting color between the blue and the orange-red region due to efficient energy transfer from Bi3+ to Mn2+, and a perfect white light emission is realized by appropriately adjusting the Mn2+ concentrations. Furthermore, the Bi3+ singly doped glass presents good thermal stability, showing about 72.3% of the observed room temperature (300 K) emission intensity at 423 K, while the thermal stability becomes lowered after Mn2+ ions are incorporated into the singly doped sample, attributed to serious thermal quenching from Mn2+. This work may help to better understand the interactions between Bi3+ and transition metal ions, and it might also be helpful in the future design of organic resin-free W-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
CRYSTAL GROWTH & DESIGN
·
2026
·
IF 3.6
Yujie Wei,Ying Lv
Single-phase white phosphors are highly desirable for achieving stable white light-emitting diodes (w-LEDs). In this work, a series of Ce3+-, Tb3+-, and Sm3+-doped as well as codoped Ca3LuAl3B4O15 (CLAB) phosphors were successfully synthesized, and white light was achieved by tuning relative doping concentrations. The phase structure, morphology, and optical properties were systematically investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence spectroscopy. Energy transfer from the parity-allowed Ce3+ ions to the parity-forbidden Tb3+ and Sm3+ ions was confirmed through spectral analysis and comparison. Under 342 nm excitation, the optimized CLAB:1%Ce3+,2.5%Sm3+,10%Tb3+ phosphor exhibits warm-white-light emission originating from three activators. In addition, the phosphor retains 71% and 42% of its initial emission intensity at 450 and 600 K, respectively, demonstrating the good thermal stability of the phosphor. By combining the optimized CLAB:1%Ce3+,2.5%Sm3+,10%Tb3+ phosphor with a commercial 340 nm ultraviolet (UV) chip, a warm w-LED was fabricated, exhibiting CIE chromaticity coordinates of (0.3631, 0.3625), a correlated color temperature (CCT) of 4419 K, and a color rendering index (CRI) of 93. This study offers a newly designed single-phase white phosphor for high-quality warm w-LEDs.
✓ 已验证
DOI
高影响因子
Optical Materials Express
·
2016
·Vol. 6
·期 11
·3574-3585
·
IF 2.657
X. Y. Liu,H. Guo,S. X. Dai,M. Y. Peng,Q. Y. Zhang
In this paper, novel Bi3+/Eu3+ co-doped white-emitting germanium-borate glasses were successfully prepared by the melt-quenching method. Their luminescent properties were evaluated using the transmission spectra, photoluminescence excitation, and emission spectra (with a temperature range of 298-573 K), and lifetime decay curves. Due to the efficient energy transfer from Bi3+ to Eu3+, tunable emitting color between the bluish-green and the orange-red region has been obtained by varying the content of Eu3+ (0-7%). Interestingly, a perfect white-light emission with CIE coordinates (X = 0.356, Y = 0.325) is realized upon the excitation at 345 nm light in the Bi3+/Eu3+ co-doped sample. More remarkably, the white-light emission glass maintains excellent color stability even at 423 K. Our results indicate that the Bi3+/Eu3+ co-doped germanium-borate glasses may be used as a potential single-phased white light-emitting matrix material for the UV converted organic-resin-free WLEDs in the future.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2020
·
IF 4.495
Qiang-Qiang Zhu,Peng-Fei Yang,Zai-Yang Wang,Peng-Cheng Hu
To obtain red-emitting luminescent material for high-power UV LED and UV LD applications, an additive-free Y 2 O 3 :Eu 3+ phosphor ceramic was successfully prepared in this work. The nitrate pyrogenation method is applied to obtain raw nanopowders with high reactivity, and a hybrid sintering method combining low-temperature presintering and subsequent hot isostatic pressing (HIP) is then applied to realize full densification of the final ceramic products. The effects of the presintering temperature on the density, microstructural, and optical properties are investigated in detail. The HIP-treated Y 2 O 3 :Eu 3+ ceramic presintered at 1450 °C exhibits a high transmittance near 80 % at 600 nm. Due to the nonuse of sintering additives, the thermal conductivity of Y 2 O 3 :Eu 3+ ceramic product reaches 10.9 Wm −1 K −1 at room temperature. The achieved Y 2 O 3 :Eu 3+ ceramic also exhibits good applicability under the excitation of a UV LED chip and UV laser light, showing promise as a color converter for high-power UV LED and UV LD applications.
研究领域:
材料科学
·
光电子学
·
陶瓷与玻璃
·
固态照明
·
热管理
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 10
·期 40
·14971-14981
·
IF 8.067
Shuai Huang,Mengmeng Shang,Minliang Deng,Yu Yan,Peipei Dang,Jun Lin
Efficiently modulating the site occupation of activators has important implications in the design of color-tunable phosphors. In this paper, we report a series of novel Sr3Sc4O9:xEu phosphors. The activators (Eu2+) selectively occupy multiple cationic sites (Sr1–3 and Sc1–4) in the Sr3Sc4O9 matrix with the increase of doping concentration, thus achieving the modulation of emission color from deep-red to white to green. The structure-dependent luminescence mechanism is investigated in detail. The PL spectrum of the Sr3Sc4O9:0.06Eu phosphor upon blue light excitation exhibits an asymmetrically broad deep-red emission band peaking at 688 nm with a FWHM ≈ 100 nm, which clearly overlaps with the absorption curves of red-phytochrome (Pr) and far-red-phytochrome (Pfr). The photoluminescence quantum yield (PLQY) is significantly improved from 2.7% to 19.18% by adopting a double-reduction strategy. The full-visible-spectrum white emission of Sr3Sc4O9:0.01Eu is achieved when excited by UV light. A full-spectrum white LED with Ra = 86 and CCT = 5040 K was packaged with a single-component white emission Sr3Sc4O9:0.01Eu phosphor. All the results suggest the utilization potential of multifunctional Sr3Sc4O9:xEu phosphors in agricultural and full-spectrum general lighting.
研究领域:
材料科学
·
光学材料
·
固态照明
·
发光与荧光粉
·
LED技术
·
无机化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）