Porous silicon-zinc sulfide nanocomposite(PS-ZnS) was prepared by in situ synthesis of ZnS via a simple polyphase reaction on the base of nano-PS. The formation of the composite was confirmed by X-ray diffraction(XRD)...Porous silicon-zinc sulfide nanocomposite(PS-ZnS) was prepared by in situ synthesis of ZnS via a simple polyphase reaction on the base of nano-PS. The formation of the composite was confirmed by X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), energy dispersive spectroscopy(EDS) and photoluminescence(PL) measurements. Based on the XRD data and the Debye-Scherrer equation, the size of the formed ZnS particles both on the surface and in the holes of the PS was calculated to be nano-scaled, ca. 5—7 nm. FE-SEM observation showed agglomeration for the ZnS particles with an average crystallite size of 30—40 nm, and the hole diameter of the PS was below 100 nm. PL measurements and CIE diagram analysis for the PS-ZnS composite samples indicated that the emitted light color from the composites could be modulated and controlled by changing the annealing conditions, from orange to violet-blue, and finally, white-light emitter of the composite was obtained.展开更多
为了研究随着三元碱土离子配比变化其正硅酸盐物相组成、发光性能的变化规律,优选高效荧光粉,同时探讨单相区和混合相区发光性能的变化内在机制,建立组分-结构-发光性能关联,本文采用高温固相法制备(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.0...为了研究随着三元碱土离子配比变化其正硅酸盐物相组成、发光性能的变化规律,优选高效荧光粉,同时探讨单相区和混合相区发光性能的变化内在机制,建立组分-结构-发光性能关联,本文采用高温固相法制备(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu系列荧光粉,共计44个样,分析其二元、三元物相组成和光谱,得出其物相组成和紫外激发发光CIE值。实验表明,(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu体系中物相组成随着组元含量存在渐变性;富Ba端形成了Ba 2SiO 4相单相区(Sr最大量含量为35%、Mg为30%),单相区随着Sr 2+、Mg 2+固溶,晶格常数减小,结晶度提高。(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu荧光粉在紫外激发下其颜色和亮度随着组元含量也呈现渐变性,Ba 2SiO 4相单相区荧光粉均为绿色荧光粉且随着Sr 2+、Mg 2+固溶荧光亮度逐渐增大(精细光谱表明单相区内Mg 2+、Sr 2+离子有促进Eu 2+离子进入高发光效率的格位的效果);Mg 2SiO 4-Sr 2SiO 4二元系列为红色荧光粉;单相区外的样品点随着Ba 2+的减少,荧光粉紫外激发荧光颜色逐渐由绿变红(混合物相中Eu离子配位空间逐渐减小,Eu离子逐渐以Eu 3+离子形式存在)。(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu系列荧光粉的相组成、结构及发光性能随组元呈现渐变性关系,借鉴相图建立方法,可建立三元色像图(由样品发射光谱得出的CIE色像点,基于散点分布建立色像图);利用三元色像图可系统性优选高效荧光粉(优选出最佳绿色和红色荧光粉样品点为:(Mg 0.3 Ba 0.65 Sr 0.05)1.95 SiO 4∶0.05Eu和(Mg 0.65 Sr 0.35)1.95 SiO 4∶0.05Eu)。展开更多
In this article upconversion luminescence of silver nanoparticles（AgNPs） coated NaYF4：Er3＋/Yb3＋phosphor nano-particles was investigated.The prepared samples were characterized through various techniques.The surfa...In this article upconversion luminescence of silver nanoparticles（AgNPs） coated NaYF4：Er3＋/Yb3＋phosphor nano-particles was investigated.The prepared samples were characterized through various techniques.The surface plasmon band is observed for prepared AgNPs by analyzing UV-vis measurements and is used to enhance the upconversion emission.From the upconversion measurement the emission bands are observed at 522,546,and 656 nm corresponding to the 2 H11/2→ 4115/2,4 S3/2→4 I15/2and 4 F9/2→4 I15/2 levels,respectively.The upconversion emission intensity of the above bands is found to enhance for sample containing 1 mmol AgNPs.Decay time of 4 S3/2 and 4F9/2 levels is found to decrease on coating of AgNPs and hence intensity enhancement is assumed due to the surface plasmon resonance（SPR） effect.展开更多
In order to solve the uncertainty of voice-to-color conversion in which one of the three voice features（loudness, tone, rhythm） is applied to control LED color, a linear conversion solution is proposed. And a chroma...In order to solve the uncertainty of voice-to-color conversion in which one of the three voice features（loudness, tone, rhythm） is applied to control LED color, a linear conversion solution is proposed. And a chromaticity diagram is defined by using hue definition on hue-saturation-lightness（HSL） hue ring and the normalization of CIE xyY which is a color standard defined by International Commission on Illumination（CIE）. The chromaticity diagram shows a linear relation between pitch and color, which is referred to conversions of other physical parameters as well. Based on the solution, red（R）, green（G） and blue（B） LEDs, the driving structure of a conversion circuit is designed and set up. The results indicate that signal processing of tone-to-color conversion is effective, from 30 Hz to 3 kHz with a resolution of 10 Hz mapped to the chromaticity diagram.展开更多
文摘Porous silicon-zinc sulfide nanocomposite(PS-ZnS) was prepared by in situ synthesis of ZnS via a simple polyphase reaction on the base of nano-PS. The formation of the composite was confirmed by X-ray diffraction(XRD), field emission scanning electron microscopy(FE-SEM), energy dispersive spectroscopy(EDS) and photoluminescence(PL) measurements. Based on the XRD data and the Debye-Scherrer equation, the size of the formed ZnS particles both on the surface and in the holes of the PS was calculated to be nano-scaled, ca. 5—7 nm. FE-SEM observation showed agglomeration for the ZnS particles with an average crystallite size of 30—40 nm, and the hole diameter of the PS was below 100 nm. PL measurements and CIE diagram analysis for the PS-ZnS composite samples indicated that the emitted light color from the composites could be modulated and controlled by changing the annealing conditions, from orange to violet-blue, and finally, white-light emitter of the composite was obtained.
文摘为了研究随着三元碱土离子配比变化其正硅酸盐物相组成、发光性能的变化规律,优选高效荧光粉,同时探讨单相区和混合相区发光性能的变化内在机制,建立组分-结构-发光性能关联,本文采用高温固相法制备(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu系列荧光粉,共计44个样,分析其二元、三元物相组成和光谱,得出其物相组成和紫外激发发光CIE值。实验表明,(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu体系中物相组成随着组元含量存在渐变性;富Ba端形成了Ba 2SiO 4相单相区(Sr最大量含量为35%、Mg为30%),单相区随着Sr 2+、Mg 2+固溶,晶格常数减小,结晶度提高。(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu荧光粉在紫外激发下其颜色和亮度随着组元含量也呈现渐变性,Ba 2SiO 4相单相区荧光粉均为绿色荧光粉且随着Sr 2+、Mg 2+固溶荧光亮度逐渐增大(精细光谱表明单相区内Mg 2+、Sr 2+离子有促进Eu 2+离子进入高发光效率的格位的效果);Mg 2SiO 4-Sr 2SiO 4二元系列为红色荧光粉;单相区外的样品点随着Ba 2+的减少,荧光粉紫外激发荧光颜色逐渐由绿变红(混合物相中Eu离子配位空间逐渐减小,Eu离子逐渐以Eu 3+离子形式存在)。(Mg 1-x-y Ba x Sr y)1.95 SiO 4∶0.05Eu系列荧光粉的相组成、结构及发光性能随组元呈现渐变性关系,借鉴相图建立方法,可建立三元色像图(由样品发射光谱得出的CIE色像点,基于散点分布建立色像图);利用三元色像图可系统性优选高效荧光粉(优选出最佳绿色和红色荧光粉样品点为:(Mg 0.3 Ba 0.65 Sr 0.05)1.95 SiO 4∶0.05Eu和(Mg 0.65 Sr 0.35)1.95 SiO 4∶0.05Eu)。
基金Project supported by the Indian Institute of Technology(Indian School of Mines),Dhanbad,Indiathe Council of Scientific&Industrial Research(CSIR),New Delhi,India(03(1303)13/EMR)
文摘In this article upconversion luminescence of silver nanoparticles（AgNPs） coated NaYF4：Er3＋/Yb3＋phosphor nano-particles was investigated.The prepared samples were characterized through various techniques.The surface plasmon band is observed for prepared AgNPs by analyzing UV-vis measurements and is used to enhance the upconversion emission.From the upconversion measurement the emission bands are observed at 522,546,and 656 nm corresponding to the 2 H11/2→ 4115/2,4 S3/2→4 I15/2and 4 F9/2→4 I15/2 levels,respectively.The upconversion emission intensity of the above bands is found to enhance for sample containing 1 mmol AgNPs.Decay time of 4 S3/2 and 4F9/2 levels is found to decrease on coating of AgNPs and hence intensity enhancement is assumed due to the surface plasmon resonance（SPR） effect.
文摘In order to solve the uncertainty of voice-to-color conversion in which one of the three voice features（loudness, tone, rhythm） is applied to control LED color, a linear conversion solution is proposed. And a chromaticity diagram is defined by using hue definition on hue-saturation-lightness（HSL） hue ring and the normalization of CIE xyY which is a color standard defined by International Commission on Illumination（CIE）. The chromaticity diagram shows a linear relation between pitch and color, which is referred to conversions of other physical parameters as well. Based on the solution, red（R）, green（G） and blue（B） LEDs, the driving structure of a conversion circuit is designed and set up. The results indicate that signal processing of tone-to-color conversion is effective, from 30 Hz to 3 kHz with a resolution of 10 Hz mapped to the chromaticity diagram.
