Advanced Optical Materials
·
2021
·Vol. 9
·期 19
·2100337
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IF 9.926
Dan Zhang,Xiangting Zhang,Baofeng Zheng,Qi Sun,Zhibo Zheng,Zhan Shi,Yanhua Song,Haifeng Zou
A series of Eu 2+ single doped Ca 9 Na 1– x Li x Sc 0.667 (PO 4 ) 7 phosphors with full-spectrum emission have been synthesized. Under the 385 nm excitation, the Eu 2+ single doped Ca 9 NaSc 0.667 (PO 4 ) 7 without Li + doping displays a broad cold white light emission with the peaks at about 480 and 610 nm. With the introduction of Li + ions, the Eu 2+ ions selectively occupy the Ca1, Ca2/Ca3, and Na sites. The variation of local environment of Eu 2+ ions caused by Li + ions enhances the luminous intensity, solves the problem of the lack of a red light component, and realizes the emission color tuning from cold white via warm white to orange. A special charge compensation method caused by Li + migration avoids the generation of defects and is beneficial to the improvement of luminescence properties. Eventually, a warm white light-emitting diode device is prepared by combining the white emitting Ca 9 Na 0.8 Li 0.2 Sc 0.667 (PO 4 ) 7 :2%Eu 2+ phosphors with 385 nm LED chip, which exhibits a high color-rendering of 92.9, low correlated color temperatures of 4529 K, and excellent color stability under working temperature. The as-reported warm white emitting Eu 2+ -doped phosphors have potential applications in full-spectrum solid-state lighting. The site engineering strategy provides an extensive guide for optimizing and designing novel single-composition white-emitting phosphor materials.
研究领域:
材料科学
·
光学工程
·
固态照明
✓ 已验证
DOI
高影响因子
ECS Journal of Solid State Science and Technology
·
2016
·Vol. 5
·期 9
·R137
·
IF 1.65
Wenjuan Bian,Yushuang Qi,Xuhui Xu,Dacheng Zhou,Yong Yang,Jianbei Qiu,Xue Yu
The influence of the introduction of Li+ ions on the upconversion (UC) properties of KLu2F7:Yb3+, Er3+ nanocrystalline has been investigated in detail. It is found that the UC emission intensity of 10 mol% Li+ ions doped KLu2F7:Yb3+, Er3+ nanocrystalline is enhanced about 13 times in comparison with that of Li+-free sample. Under the excitation of 980 nm laser diode (LD), a significant improvement of the green to red emission ratio (GRR) in the 10 mol% Li+-doped sample is observed by increasing pump power density. Li+ ions could occupy the cationic sites or the interstitial sites in the KLu2F7 host matrix, which probably eliminate the defect states via the charge compensation and tailor of the crystal field, leading to the promotion of the UC emission efficiency. Thus, the introduction of Li+ ions provides new opportunities for enhancing the scope of applications of Yb3+, Er3+ doped KLu2F7 nanocrystalline ranging from infrared solar cells to volumetric multiplexed bio-probe.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
OPTICAL MATERIALS
·
2016
·
IF 2.183
Renping Cao,Wenjie Luo,Haidong Xu,Zhiyang Luo,Qianglin Hu,Ting Fu,Dedong Peng
YbAlO 3 :Mn 4+ , YbAlO 3 :Mn 4+ , Li + , and YbAlO 3 :Mn 4+ , Mg 2+ phosphors are synthesized by high temperature solid-state reaction method in air. Their crystal structures and luminescence properties are investigated. Photoluminescence excitation (PLE) spectrum monitored at 677 nm contains broad PLE band with three PLE peaks located at ∼318, 395, and 470 nm within the range 220–600 nm. Emission spectra with excitation 318 and 470 nm exhibit three emission band peaks located at ∼645, 677, and 700 nm in the range of 610–800 nm and their corresponding chromaticity coordinates are about ( x = 0.6942, y = 0.3057). The possible luminous mechanism of Mn 4+ ion is analyzed by the simple energy level diagram of Mn 4+ ion. The optimum Mn 4+ -doped concentration in YbAlO 3 :Mn 4+ phosphor is about 0.4 mol% and the luminescence lifetime of YbAlO 3 :0.4%Mn 4+ phosphor is ∼0.59 ms. Emission intensity of YbAlO 3 :0.4%Mn 4+ phosphor can be enhanced ∼6 times after Mg 2+ ion is co-doped and it is ∼2 times when Li + ion is co-doped. The content in the paper is useful to research new Mn 4+ -doped luminescence materials and improve luminescence property of other Mn 4+ -doped phosphors.
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 ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
Lei Hu,Ruohan Lu,Lingfei Tang,Ran Xia,Chunfu Lin,Zhibin Luo,Yongjun Chen,Jianbao Li
As a recently developed anode material for lithium-ion batteries, Ti 2 Nb 10 O 29 shows high theoretical/practical capacities and safety, but suffers from a poor rate capability due to its insulator nature and insufficient Li + -ion diffusion coefficient . To tackle this issue, a strategy combining nanosizing, Cr 3+ –Nb 5+ co-doping and carbon nanotube (CNT) compositing is employed. A novel TiCr 0.5 Nb 10.5 O 29 /CNTs nanocomposite with 9.1 wt% CNTs is fabricated by a direct hydrolysis process followed by calcination in N 2 . The Cr 3+ –Nb 5+ co-doping significantly improves the electronic conductivity and Li + -ion diffusion coefficient of Ti 2 Nb 10 O 29 by three orders and one order of magnitude, respectively. The CNT compositing not only enhances the electrical conduction among the TiCr 0.5 Nb 10.5 O 29 particles but also hinders the particle growth in the hydrolysis process, leading to the small particle sizes. Due to the synergistic effect of these advantages, the TiCr 0.5 Nb 10.5 O 29 /CNTs nanocomposite exhibits a high rate capability with a high capacity of 206 mAh g −1 at 20 C, surpassing those of Ti 2 Nb 10 O 29 (145 mAh g −1 ) and TiCr 0.5 Nb 10.5 O 29 nanoparticles (187 mAh g −1 ). Additionally, TiCr 0.5 Nb 10.5 O 29 /CNTs delivers a high reversible capacity (297 mAh g −1 at 0.1 C) and cyclic stability (95.0% capacity retention after 100 cycles at 10 C). This good electrochemical performance reveals that TiCr 0.5 Nb 10.5 O 29 /CNTs can be an advanced anode material for high-performance Li + -ion storage.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2022
·
IF 16.744
Zhixiang Meng,Meiling Wang,Xun Cao,Tian Wang,Yongchao Wang,Yike Xu,Weifeng Liu,Lin Chen,Yizhong Huang,Xuguang Liu
Li + ion-sieve (LIS) films, foams, or granules have been fabricated to immobilize LIS to overcome powder loss for Li extraction from seawater. However, the practical application is still restricted by their low swelling ability and poor flexibility to withstand harsh marine environment for a long time. Here, a highly elastic interconnected porous LIS nanocomposite hydrogel with tunable pore structure and flexibility, as well as good swelling property, is prepared by using LIS (viz. λ-MnO 2 ) as a pore self-modifier during the in-situ fabrication of polypyrrole (PPy) and polyvinyl alcohol (PVA) interpenetrating hydrogel (denoted as λ-MnO 2 @IG). In addition to physical confinement interactions, the strong coordination/chelation and electrostatic interactions between λ-MnO 2 nanoparticles and polymer chains enable well-dispersed λ-MnO 2 nanoparticles to be confined in a rich network structure. Even at a marine environment (pH 8.3), the λ-MnO 2 @IG hydrogel exhibits superior Li + adsorption performance (20.6 mg g −1 HMO), outperforming most adsorbents containing LIS. Specially, the porous hydrogel is easily recyclable and exhibits super-stable cyclic Li extraction performance, which are directly attributable to the further-improved pore structure in continuous regeneration process. This study provides a self-regulating strategy to design LIS porous hydrogels with controllable porosity, high flexibility, good swelling ability, and excellent cycle stability to address the growing Li + demanding challenges.
研究领域:
材料科学
·
环境工程
·
化学工程
✓ 已验证
DOI
高影响因子
Journal of Energy Chemistry
·
2022
·
IF 13.599
Zhenghao Li,Wei Wang,Xinmiao Liang,Jianlin Wang,Yonglin Xu,Wei Li
It is well established that paper-based separators display short-circuit risk in lithium-ion batteries due to their intrinsic micron-sized pores. In this research, we have adjusted pore structure of paper by fiber swelling in liquid electrolyte. Specifically, the paper-based separator is prepared by propionylated sisal fibers through a wet papermaking process. Scanning electron microscope (SEM) and multi-range X-ray nano-computed tomography (CT) images display strong swelling of modified fibers after electrolyte absorption, which can effectively decrease the pore size of separator. Due to the high electrolyte uptake (817 wt%), paper-based separator exhibits ionic conductivity of 2.93 mS cm −1 . 7 Li solid-state NMR spectroscopy and Gaussian simulation reveal that the formation of local high Li + ion concentration in the separator and its low absorption energy with Li + ion (62.2 kcal mol −1 ) is conducive to the ionic transportation. In particular, the assembled Li/separator/LiFePO 4 cell displays wide electrochemical stability window (5.2 V) and excellent cycle performance (capacity retention of 96.6% after 100 cycles at 0.5 C) due to the reduced side reactions as well as enhanced electrolyte absorption and retention capacity by propionylation. Our proposed strategy will provide a novel perspective to design high-performance bio-based separators to boost the development of clean and sustainable energy economy.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）