OPTICAL MATERIALS
·
2021
·
IF 3.08
Kun Zhu,Haitao Lv,Yanmin Wang,Zhidong Pan
Sm 3+ doped calcium stannate (CaSnO 3 :Sm 3+ ) and (Sm 3+ , Zr 4+ )-co-doped calcium stannate (CaSnO 3 :Sm 3+ , Zr 4+ ) photoluminescent phosphors were synthesized via co-precipitation and subsequent sintering in oxidizing atmosphere at 1400 °C for 60 min with SnCl 4 ·5H 2 O, CaCl 2 ·2H 2 O, ZrO(NO 3 ) 2 · x H 2 O and Sm 2 O 3 as main raw materials. The synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, photoluminescent spectroscopy, luminescent decay curves, afterglow spectroscopy and thermo-luminescent glow curves. The results show that CaSnO 3 pure phase is synthesized in co-precipitation reaction at an optimum molar ratio of CaCl 2 ·2H 2 O:SnCl 4 ·5H 2 O of 1.4:1.0 and subsequent sintering at 1400 °C for 60 min. Calcium stannate as a host matrix can be doped with Sm 3+ ions or co-doped with Sm 3+ /Zr 4+ ions for the formation of white photoluminescent phosphors. CaSnO 3 :0.03Sm 3+ phosphor has an optimum photoluminescent intensity. Also, the fluorescent emission intensity of CaSnO 3 :0.03Sm 3+ ，0.04Zr 4+ phosphor under excitation of 365 nm wavelength can be enhanced due to Zr 4+ ions doping at an optimum doping amount y of 0.04. The CIE 1931 chromaticity coordinates change from (0.3600, 0.3535) for CaSnO 3 :0.03Sm 3+ phosphor to (0.3622, 0.3574) for CaSnO 3 :0.03Sm 3+ , 0.04Zr 4+ phosphor as the average crystalline size decreases from 71.5 to 68.3 nm and the unit cell volume increases from 0.2686 to 0.2775 nm 3 . In addition, the electron transition mechanism for the photoluminescent and long afterglow properties was also discussed.
研究领域:
材料科学
·
光学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Science Advances
·
2023
·Vol. 9
·期 37
·
IF 13.6
Xudong Hu,Sihan Luo,Jing Leng,Chujie Wang,Yiyang Chen,Jun Chen,Xiaoming Li,Haibo Zeng
X-ray imaging based on a single gray level shows visual blind parts and affects accurate judgment in some situations. Color-cognized x-ray imaging will boost the recognition capability, which has not yet been reported. Here, we propose a quartz-assisted chromatic x-ray imaging model based on metal halide nanocrystal (NC) stacked scintillators. Mutually inactive (BA)2PbBr4:Mn and Cs3Cu2I5:Tl enable x-ray energy- or density-dependent radioluminescence (RL) color variation. The upper scintillator light yield and the bottom scintillator transmittance are enhanced by elaborate in situ passivation of phenethylamine bromide and NC orientation regulation, respectively. Imaging targets with different densities are distinguished on RL spectra, and the color coordinates shift linearly on CIE 1931. An algorithm balances the image details of different gray areas and enhances the visual perception by color filling. This work provides color recognition between objects with different densities and takes a step toward chromatic x-ray imaging applied to practical scenarios.
研究领域:
医学成像
·
材料科学
·
纳米技术
·
光学
✓ 已验证
DOI
高影响因子
Advanced Optical Materials
·
2022
·Vol. 10
·期 16
·2200217
·
IF 10.05
Chuying Wang,Ya-Kun Wang,Ziliang Li,Jingwei Luo,Randy Sabatini,Tao Zhang,Edward H. Sargent,Zhengtao Deng
Recently, metal halide perovskites have attracted considerable interest as highly emissive phosphors for use in white light-emitting diodes (WLEDs). In perovskites, the migration of halide anions between green-emitting bromide (e.g., CsPbBr 3 ) and red-emitting iodide (e.g., CsPbI 3 ) materials is one obstacle to application. Here perovskite WLEDs that do not suffer from the anion exchange problem are reported: this is done by developing green-emitting single-layer sheets of (RNH 3 ) 2 PbI 4 (R = C 18 H 35 –, C 12 H 25 –, and C 8 H 17 –) and uniting these with red-emitting CsPbI 3 perovskite quantum dots (QDs). It relies on self-assembly from ligand-capped CsPbI 3 nanocrystals to form single-layer sheets of (C 18 H 35 NH 3 ) 2 PbI 4 : via judicious selection of alkylamines and alkyl acids, (RNH 3 ) 2 PbI 4 single-layer sheets that exhibit bright and stable green emission with well-defined single-layer thickness are produced. Emission from 505, 512 to 536 nm is tuned and a narrow (<20 nm) linewidth is retained. Perovskite LEDs that produce white light with chromaticity coordinates (0.32, 0.33) and color gamut that reaches 117% National Television System Committee (NTSC) in the International Commission on Illumination (CIE) 1931 color space are demonstrated.
研究领域:
材料科学
·
光电技术
·
光子学
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2023
·
IF 13.3
Yongfeng Liu,Xiuwen Shao,Zhaoju Gao,Qingyu Xie,Yupeng Ying,Xiaolin Zhu,Zhangcheng Pan,Jinpeng Yang,Hao Lin,Xiaosheng Tang,Weiwei Chen,Wei Pei,Yusong Tu
Inorganic CsPbX 3 perovskite quantum dots (PeQDs) show great potential in white light-emitting diodes (WLEDs) due to excellent optoelectronic properties, but their practical application is hampered by low photoluminescence quantum yield (PLQY) and especially poor stability. Herein, we developed an in-situ and general multidentate ligand passivation strategy that allows for CsPbX 3 PeQDs not only near-unit PLQY, but significantly improved stability against storage, heat, and polar solvent. The enhanced optical property arises from high effectiveness of the multidentate ligand, diethylenetriaminepentaacetic acid (DTPA) with five carboxyl groups, in passivating uncoordinated Pb 2+ defects and suppressing nonradiative recombination. First-principles calculations reveal that the excellent stability is attributed to tridentate binding mode of DTPA that remarkably boosts the adsorption capacity to PeQD core. Finally, combining the green and red PeQDs with blue chip, we demonstrated highly luminous WLEDs with distinctly enhanced operation stability, a wide color gamut of 121.3% of national television system committee, standard white light of (0.33,0.33) in CIE 1931, and tunable color temperatures from warm to cold white light readily by emitters’ ratio. This study provides an operando yet general approach to achieve efficient and stable PeQDs for WLEDs and accelerates their progress to commercialization.
研究领域:
材料科学
·
光电技术
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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