POLYMERS FOR ADVANCED TECHNOLOGIES
·
2020
·Vol. 31
·期 8
·1744-1751
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IF 2.578
Zhongyang Wang,Ali Hasnain,Xujun Sun,Ying Han,Dongshun Liu,Xiaohua Tan,Xiang-Kui Ren,Yakai Feng
In recent years, fluorescent carbon dots (CDs) have been developed and showed potential applications in biomedical imaging and light-emitting diodes (LEDs) for their excellent fluorescent properties. However, it still remains a challenge to incorporate fluorescent CDs into the host matrix in situ to overcome their serious self-quenching. Herein, a one-pot hydrothermal method is used to prepare nano-zirconia with CDs (CDs@ZrO 2 ) nanoparticles. During the reaction, CDs and nano-zirconia are generated simultaneously and connected with silane coupling agent. The CDs@ZrO 2 nanoparticles exhibit tunable emission wavelength from 450 to 535 nm emission by regulating the content of citric acid in the feed. The quantum yield of the CDs@ZrO 2 is up to 23.8%. Furthermore, the CDs@ZrO 2 nanoparticles with regulable fluorescence emission can be used for the fluorescent material to prepare white LEDs. The prepared LED has significant white light emission with color coordinates of (0.30, 0.37) and its color rendering index (CRI) is 67.1. In summary, we have developed the solid-state CDs@ZrO 2 nanoparticles with tunable emission by a valuable strategy, that is, one-pot method, for white LEDs.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Dan Zhao,Shi-Rui Zhang,Yan-Ping Fan,Bao-Zhong Liu,Ya-Nan Li,Lin-Ying Shi,Shao-Jie Dai
Developing broad-band-emitting phosphors is very important to light-emitting diode (LED) lighting and displays. We introduced Eu2+ to solid solutions K2YZr1–yHfy(PO4)3 with a langbeinite-type structure to prepare a series of new phosphors. In this structure, two K+ sites could be occupied by Eu2+ cations to provide two different kinds of coordination environments, leading to broad emitting bands in the range of 390–700 nm. The coordination circumstance of Eu2+ was analyzed by Gaussian fitting and time-resolved emission spectra. Furthermore, the emitting intensity and thermal stability can be improved by modulating the crystalline field via substituting Zr4+ by Hf4+. When the Zr4+ was fully substituted by Hf4+, the external quantum efficiency increased by 53.75%, giving a bright cyan emission. Finally, an archetype white-LED lamp was made using cyan phosphor K2YHf(PO4)3:0.04Eu, red phosphor CaAlSiN3:Eu2+, and a 365 nm LED chip, which realized an applicable color rendering index (Ra = 81) and a correlated color temperature (CCT = 3792 K).
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
DYES AND PIGMENTS
·
2020
·
IF 4.613
Sujie Han,Xipao Chen,Yaoping Hu,Lei Han
As a newly discovered photoluminescent material, carbon dots (CDs) have shown promising performance in many fields. However, due to aggregation-caused fluorescence quenching, most of CDs are poorly emissive in the solid state, which severely restricts their wide applications, especially in the optoelectronic devices . To overcome this problem, herein, we design a novel kind of self-quenching-resistant N , P -doped CDs, using polyethyleneimine (PEI), phosphoric acid , and ethanol as raw ingredients. The as-synthesized CDs are amorphous and contain abundant surface PEI chains which properly separate the individual carbon core and prevent the direct π–π interaction. Such a unique structure conquers self-quenching during aggregation, and gives CDs a bright blue fluorescence in solid state without any other additional matrices. By taking advantage of their excellent optical properties , the CD powers, combined with red emissive europium metal-organic frameworks, are successfully employed as hybrid phosphors for construction of white light-emitting diodes exhibiting a Commission Internationale de L'Eclairage (CIE) coordinate of (0.33, 0.33).
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
Small
·
2019
·Vol. 16
·期 1
·1905266
·
IF 10.856
Guangqi Hu,Yuqiong Sun,Jianle Zhuang,Xuejie Zhang,Haoran Zhang,Mingtao Zheng,Yong Xiao,Yeru Liang,Hanwu Dong,Hang Hu,Bingfu Lei,Chaofan Hu,Yingliang Liu
Commercial white light-emitting diodes (LEDs) have the undesirable characteristics of blue-rich emission and low color rendering index (CRI), while the constituent quantum dots (QDs) suffer from aggregation-induced fluorescence quenching and poor stability. Herein, a strategy is developed to assemble tricolor QDs into a polysiloxane matrix using a polymer-mediated hybrid approach whereby the hybrid composite exhibits a significant enhancement of aggregation-dispersed emission, outstanding photostability, high thermal stability, and outstanding fluorescence recovery. Using the as-prepared hybrid fluorescent materials, the fabricated LEDs exhibit solar spectrum-simulated emission with adjustable Commission Internationale de L'Eclairage coordinates, correlated color temperature, and a recorded CRI of 97. Furthermore, they present no ultraviolet emission and weak blue emission, thus indicating an ideal healthy and high-CRI white LED lighting source.
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Coatings
·
2021
·Vol. 11
·期 5
·581
·
IF 2.881
Linyuan Lian,Youyou Li,Daoli Zhang,Jianbing Zhang
InP quantum dots (QDs) are promising down-conversion phosphors for white light LEDs. However, the mainstream InP QDs synthesis uses expensive phosphorus source. Here, economic, in situ-generated PH3is used to synthesize InP QDs and a two-step coating of ZnS shells is developed to prepare highly luminescent InP/ZnS/ZnS QDs. The QDs show a photoluminescence quantum yield as high as 78.5%. The emission can be tuned by adjusting the halide precursor and yellow emissive InP/ZnS/ZnS QDs are prepared by judiciously controlling the synthetic conditions. The yellow QDs show suppressed thermal quenching and retain >90% room temperature PL intensity at 150 °C for the growth solution. Additionally, the PL spectrum matches with the eye sensitivity function, resulting in efficient InP QD white light LEDs.Keywords:InP;quantum dots;core/shell;InP/ZnS;thermal quenching
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2017
·Vol. 5
·期 39
·10241-10250
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IF 5.256
Mengmeng Zhu,Yuexiao Pan,Luqing Xi,Hongzhou Lian,Jun Lin
Mn4+-activated red phosphors have attracted considerable attention as promising red components in the spectra of white light emitting diodes (WLEDs) to achieve warm white light with superior performance. Herein, a novel red phosphor based on Mn4+-doped dodec-fluoride Li3Na3Al2F12:Mn4+ (LNAF:Mn) with microcubic morphology was obtained at room temperature. To elucidate the underlying relationship between the crystal structure and photoluminescence of LNAF:Mn, a phosphor LiNa2AlF6:Mn4+ with similar composition has been prepared, and their morphology and optical properties were comparatively investigated. The emission of the red phosphor LNAF:Mn is blue shifted compared to LiNa2AlF6:Mn4+ suggesting that the chromaticity coordinates of LANF:Mn are closer to the ideal red point (0.67, 0.33). The luminescence properties of LNAF:Mn have been improved by optimizing the synthetic conditions. This work exhibits a strategy to explore a novel Mn4+-doped fluoride except for the identified hexa-fluorides. Employing the as-prepared red LNAF:Mn as a red component, a high-performance WLED with a correlated color temperature (CCT) of 3874 K and a color rendering index (CRI) of 90.6 was obtained. This suggests the phosphor is a potential commercial red phosphor in warm WLEDs.
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
NANOTECHNOLOGY
·
2018
·Vol. 30
·期 7
·075704
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IF 3.404
Weiwei Chen,Xiaosheng Tang,Zhigang Zang,Yue Shi,Zhaoqi Yang,Juan Du
Doping of Mn2+ into semiconductor nanocrystals has been demonstrated to endow them with novel electronic, optical and magnetic functionalities. In this paper, Mn-doped CsPbX3 (X = Br, Cl) quantum dots (QDs) were synthesized at room temperature via a facile strategy by introducing dimethyl sulfoxide (DMSO)-MnBr2/PbX2 composite as a precursor. The excitonic emission spectra of the as-obtained Mn-doped CsPbX3 QDs can be tuned from 517 nm to 418 nm by adjusting the ratio of PbBr2/PbCl2 precisely, and the luminescence mechanism of the doped QDs is discussed in detail. Moreover, the highest photoluminescence quantum yield of the Mn2+ emission achieves 36.7%, which is comparable with QDs prepared by the conventional hot-injection method. Depending on the ratios of PbPb2/PbCl2, the energy transfer rate from the band-edge to Mn2+ excited state is in the range of 0.006–20.42 × 107 s−1. Furthermore, white light-emitting diodes (LEDs) were successfully fabricated by combining the as-prepared Mn-doped CsPbX3 QDs with commercial UV GaN chips, and the high luminous efficiency of the as-prepared white LEDs was developed to 55.9 lm W−1. This work strongly supports the fact that Mn-doped CsPbX3 QDs are promising materials for application in lighting and displaying fields.
研究领域:
材料科学
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光学
·
纳米技术
✓ 已验证
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DOI
PubMed
高影响因子
CHEMICAL PHYSICS LETTERS
·
2017
·
IF 1.815
Yuguo Yang,Jing Li,Bing Liu,Yuanyuan Zhang,Xianshun Lv,Lei Wei,Xuping Wang,Jianhua Xu,Huajian Yu,Yanyan Hu,Huadi Zhang,Ling Ma,Jiyang Wang
A series of YAG:Ce 3+ /Eu 3+ , YAG:Ce 3+ /Eu 3+ /Bi 3+ and YAG:Ce 3+ /Gd 3+ phosphors were synthesized by a co-precipitation method. The results suggest that all of phosphors have the cubic phase and nearly spherical morphology. However, the red emission can be produced by codoping Eu 3+ and Eu 3+ /Bi 3+ ions in YAG:Ce 3+ , and the codoped Gd 3+ ions can induce the red-shift of Ce 3+ emission. These results suggest that the Eu 3+ , Eu 3+ /Bi 3+ and Gd 3+ ions can be used to decrease the correlated color temperature and increase the color-rendering index of white light-emitting diodes based on InGaN blue chip and YAG:Ce 3+ phosphors.
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
·
2017
·Vol. 5
·期 36
·9255-9263
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IF 5.256
Luqing Xi,Yuexiao Pan,Mengmeng Zhu,Hongzhou Lian,Jun Lin
A kind of red-emitting phosphor NaKSnF6:Mn4+ (NKSF:Mn) has been obtained from NaF and KF with a certain molecular ratio in HF solution at room temperature. The phosphor NKSF:Mn exhibits superior optical properties including high color purity with narrow-band emissions as well as better chromaticity coordinates compared to the red phosphors Na2SnF6:Mn4+ (NSF:Mn) and K2SnF6·H2O:Mn4+ (KSFH:Mn). The composition and structure of NKSF:Mn have been identified by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and transmission electron microscopy (TEM). The formation mechanism of NKSF:Mn is discussed and the morphology, thermal stability, and optical properties of NKSF:Mn have been investigated. The luminescence intensity of NKSF:Mn has been improved by optimizing synthetic parameters. A white light-emitting diode (WLED) fabricated using a blue GaN chip, a yellow YAG:Ce phosphor, and the as-prepared red phosphor NKSF:Mn exhibits superior warm white light with a color rendering index (CRI) of 90.3 at a correlated color temperature (CCT) of 3746 K.
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2018
·Vol. 10
·期 47
·22237-22251
·
IF 7.233
Guo-Hui Pan,Huajun Wu,Shuai He,Liangliang Zhang,Zhendong Hao,Xia Zhang,Jiahua Zhang
The most common yellow phosphor for wLEDs, Y3Al5O12:Ce3+ (YAG:Ce3+), suffers from a deficiency of red in its spectral content of light. In this paper, a new strategy is provided to tailor the Ce3+ spectral profile through surface-located dye molecules of ATTO-Rho101, which feature intense, broad absorption in the green-yellow spectral region of Ce3+ emission as well as bright red emission. Sphere-shaped and highly dispersed micrometer and nanometer-sized YAG:Ce3+ (micro/nano-YAG:Ce3+) was synthesized through a modified solvothermal method. Surface SiO2 coating and simultaneous dye embedding were performed on the solvothermally derived YAG:Ce3+, heat-treated micro-YAG:Ce3+ and commercial phosphors. Efficient radiative transfer/reabsorption from Ce3+ in the inner core of YAG to the dye molecules in the SiO2 outer shell, irrespective of the size of the phosphors, was demonstrated in the accumulated YAG:Ce3+@SiO2 + dye powder upon blue light excitation; this enhanced its red emission. Fluorescence microscopy was demonstrated to be a powerful tool to identify the reabsorption phenomenon of the powdered materials. Packaging the heat-treated micro-YAG:Ce3+@SiO2 + dye phosphors on blue LED chips yielded a warm wLED (Ra ∼ 93), but an Ra of only ∼79 was obtained for the wLED with commercial YAG:Ce3+@(SiO2 + dye)5 due to the low concentration of phosphors dispersed in the epoxy resin and the resulting decreased reabsorption by dye molecules. Surface-protonated amine species were found to induce Ce3+ → Ce4+ oxidation upon activation by heating or photoirradiation and then quench the photoluminescence (PL) of micro-YAG:Ce3+ even after surface modification by SiO2, YAG or being embedded in an epoxy resin matrix. High calcination temperatures greatly improved the PL stability of micro-YAG:Ce3+ through the removal of surface-capped species. The dye in the silica matrix showed high stability against heating and irradiation due to the so-called “caging effects”; however, decreased photo-stability was found in commercial YAG:Ce3+@(SiO2 + dye)5 due to the incomplete and/or loose SiO2 layer grown during multiple surface modifications.
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DALTON TRANSACTIONS
·
2022
·Vol. 51
·期 11
·4414-4422
·
IF 4.569
Zhi Wang,Xu Li,Mingyang Li,Jinxing Zhao,Zhenyang Liu,Dawei Wang,Li Guan,Fenghe Wang
With the increasing demand for new inorganic functional materials, more and more attention is paid to rare earth ion doped luminescent materials. In this work, an Eu2+ doped Ba4La6O(SiO4)6 phosphor was synthesized by the high temperature solid-phase method. In the phosphor, two Ba2+ sites could be occupied by Eu2+ cations to provide two different kinds of coordination environments, resulting in broad emitting bands in the range of 450–630 nm and ultra-wide excitation bands in the range of 250–500 nm. The presence of two different Eu2+ emitting centers is verified by measuring the photoluminescence spectra and decay curves in Ba4La6O(SiO4)6 phosphors. The temperature dependence of emission intensity and full width at half maximum of Eu2+ in the range of 293–453 K were investigated systematically. The substitution of Ba2+ by Sr2+ can adjust the crystal field; thus, the luminous intensity was improved by 2.07 times and T50 was increased from 380 K to 453 K. Due to the Sr2+ ion doping, some of the Eu3+ ions cannot be reduced and remain in the trivalent state. In addition, by integrating the as-prepared Ba1.42Sr2.5La6O(SiO4)6:Eu phosphor, commercial blue and red phosphors, and a 385 nm LED chip, a white-LED lamp was made, which realized an applicable color rendering index (Ra = 94.6). For the Ba0.42Sr3.5La6O(SiO4)6 phosphor, the emission can be shifted from yellow to green and to yellow by excitation wavelength variation from 250 to 360 and 480 nm, which proves that the phosphor is a promising candidate for anti-counterfeiting applications.
研究领域:
材料科学
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光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 32
·11010-11016
·
IF 6.4
Fan Chen,Xiao-Jun Wang,Wenhao Bai,Xuehu Zhang,Wen Hao,Changhua Zhang,Tongtong Xuan
Zero-dimensional (0D) lead-free halide perovskites are emerging as promising light-emitters, which can be applied as light conversion materials for illumination and display. Herein, we prepared a series of Sb3+:Rb2InCl5·H2O perovskites by a simple and efficient coprecipitation method. The Rb2InCl5·H2O perovskite gives no emission due to the parity-forbidden transition. When Sb3+ is doped into Rb2InCl5·H2O, radiative transition occurs. Under 365 nm excitation, the Sb3+:Rb2InCl5·H2O perovskites show an intense orange-red emission peak at 615 nm, ascribed to the 3P1 to 1S0 transition of Sb3+. The brightest luminescence of Sb3+:Rb2InCl5·H2O was achieved by doping 40%Sb3+, with a high photoluminescence quantum yield (PLQY) of 62.1% and an external quantum efficiency (EQE) of 30.2%. Furthermore, the prepared Sb3+:Rb2InCl5·H2O perovskite exhibits a distinguished thermal stability. At 150 °C, its PL intensity remains 68% of that measured at room temperature, with a high thermal activation energy of 0.184 eV. By combining Sb3+:Rb2InCl5·H2O with a blue-emitting Eu2+:BaMgAl10O17 (Eu2+:BAM) phosphor, bright warm-white light with a color rendering index of 88 and a correlated color temperature of 3242 K was achieved. To sum up, the prepared Sb3+:Rb2InCl5·H2O orange-red perovskites have the advantages of suitable excitation and emission peak positions, high emission intensity, high PLQY and EQE, excellent stability, and environmental friendliness, making them very attractive in the field of lighting and displays.
研究领域:
材料科学
·
光学
✓ 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）