Speckle image holography modulated full-color organic light-emitting diodes with high efficiency and engineered emission profile

Enlightened by holography metasurfaces for controlling the propagation of light, speckle image holography nanostructures were introduced into both fluorescent and phosphorescent OLEDs in order to achieve high efficiency and engineered emission profile. The resulting current efficiency and external quantum efficiency of the nanostructured fluorescent green emission OLEDs were enhanced by up to 99% and 104%, respectively. This enhancement feature is comparable to that of phosphorescent red- and blue-emission OLEDs. Furthermore, the enhancement ratios were retained approximately as a constant when the viewing angle varied from −60° to 60° for all three color devices. Experimental and theoretical results directly prove that the light steering is independent of the emission materials, the wavelength, radiation angle, and the polarization of the emitted light. We anticipate this paradigm may offer new opportunities for high-end optoelectronic designs and applications.     

Tunable and high-color-rendering white light emissions in full visible spectral range in Ag-aggregates/Sm3+ co-doped germanate glass fluorophors

To achieve a tunable and high-color-rendering white light emission in full visible spectral range, the Ag-aggregates/Sm³⁺ co-doped germanate glass fluorophors were prepared by a melt-quenching method. Under the excitation of different wavelengths, the intense broadband emissions covering full visible spectral range from blue to red were gained in the germanate glasses only containing Ag-aggregates. From the optical spectral analyses, it was found that with increasing the excitation wavelengths, the emission peak position exhibits red-shift. However, the red component in the emission spectra is still of relative lack for realizing high quality white light, therefore Sm³⁺ was introduced as co-dopant to supply the red spectral component. In this way, a series of chroma-tunable and full-color-emitting white lights with color coordinates from (0.26, 0.25) to (0.30, 0.32) were successfully realized based on adjusting the excitation wavelengths and Sm³⁺ concentration. Particularly, the color rendering index (CRI) up to 97.6 was achieved. Furthermore, the luminescence thermal stability of Ag-aggregates/Sm³⁺ co-doped germanate glass fluorophors was investigated based on the Arrhenius model, and the corresponding ΔE values for Ag aggregates and Sm³⁺ emissions were confirmed to be 0.25 and 0.19 eV, respectively. In addition, a temperature sensing model was established based on the luminescence intensity ratio of Ag-aggregates to Sm³⁺, and the thermochromatic property of Ag-aggregates/Sm³⁺ co-doped germanate glasses was also evaluated. It was found that the luminescence color coordinates of Ag-aggregates/Sm³⁺ co-doped glass fluorophors always lie in the white light region when the sample temperature increases from 301 to 693 K, thus indicating that Ag-aggregates/Sm³⁺ co-doped glass fluorophors have potential application in solid-state lighting sources as a single-component white lighting material.     

新型白光LED用SrMg_2(PO_4)_2单-基质荧光粉

本文通过高温固相法合成了紫外光LED用SrMg2(PO4)2为基质Eu2+,Tb3+和Mn2+为激活剂的白色荧光粉。采用XRD对荧光粉的结构和相纯度进行分析,Eu2+、Tb3+及Mn2+的加入对其结构没有明显的影响,且无杂相生成;当用Ca部分取代Sr时Eu2+和Mn2+的发射带分别发生红移和蓝移且二者之间存在着明显的能量传递;当引入共激活剂Tb3+时对其荧光光谱进行了详细研究,发现Eu2+和Tb3+,Eu2+和Mn2+之间存在部分的能量传递,通过调整它们的相对掺杂浓度可以得到发白光的荧光粉。     

CaSc2O4:Eu: A tunable full-color emitting phosphor for white light emitting diodes

We report an intense full-color emission originating from ⁵D_0,1,2,3 to ⁷F_0,1,2,3,4 transitions of Eu³⁺ in CaSc₂O₄ upon 395 nm excitation. The emission spectra vary with increasing Eu³⁺ concentration, demonstrating tunable color coordinates from white to red region in the CIE chromaticity diagram. Considering the relaxation from ⁵D_J to ⁵D_J−1 through cross energy transfer, the Eu³⁺ concentration dependent emission spectra are well simulated based on the analysis of steady state rate equations and the measured lifetimes of the ⁵D_J levels. It is suggested that CaSc₂O₄:Eu³⁺ could be a potential single-phased full-color emitting phosphor for near-ultraviolet InGaN chip pumped white light emitting diodes.     

有机电致发光显示器件的最新发展

有机电致发光器件(OLEDs)具有驱动电压低、亮度大、效率高、能实现大面积平板彩色显示以及柔性显示等优点,在平板显示领域引起广泛的关注,近年来成为国际上的研究热点,前景诱人.简要介绍了有机电致发光器件的结构、发光原理、主要特点及3种主要有机电致发光器件,并讨论了该领域的研究热点问题.     

基于全显色结构的三组纬提花织物混色特征研究

在全显色结构的基础上,设计满足三组纬全显色的缎纹过渡基本组织,通过配置三组纬色彩组合及比例来探讨该类提花织物的混色特征。建立以红黄绿为色彩组合的12枚组织和24枚组织的三组纬色卡,对比12枚组织试样与24枚组织试样的色彩效果,分析12枚组织试样实物和模拟图的色彩差异,揭示三组纬同时全显色时的混色效果。混色结果表明:织物混色与计算机混色原理的差异导致实物与模拟图的色彩存在一定差距,但基于全显色结构的三组纬提花织物具有独特的混色特征,具有不可替代性,其混合色彩规律的研究为该类提花织物的色彩仿真和创新设计提供依据。     

叠花效果数码提花织物设计实践

叠花效果织物为全真丝提花织物,应用数码提花技术和提花织物全显色组合结构进行设计。采用分层组合的提花织物设计方法,可以使机织物表面的经纬纱线产生完全不覆盖的全显色效果。将2组图案进行数码化设计组合,配合全显色组合结构,制织的织物表面具有独特的叠花效果。文章以海之韵主题作品为例,对产品构思、设计流程和方法等进行详细说明,为提花产品的创新设计提供一种有益的借鉴。