Color-stable,reduced efficiency roll-off hybrid white organic light emitting diodes with ultra high brightness

High-brightness and color-stable two-wavelength hybrid white organic light emitting diodes （HWOLEDs） with the configuration of indium tin oxide （ITO）/ N, N, N, N-tetrakis（4-methoxyphenyl）-benzidine （MeO-TPD）： tetrafluoro-tetracyanoqino dimethane （F4-TCNQ）/N,N-di（naphthalene-1-yl）-N,N-diphenyl-benzidine （NPB）/ 4,4-N,N-dicarbazolebiphenyl （CBP）： iridium （III） diazine complexes （MPPZ） 2 Ir（acac）/NPB/2-methyl-9,10-di（2-naphthyl）anthracene （MADN）： p-bis（p-N,N-di-phenyl-aminostyryl）benzene （DSA-ph）/bis（10-hydroxybenzo[h] quino-linato）beryllium complex （Bebq2）/LiF/Al have been fabricated and characterized. The optimal brightness of the device is 69932 cd/m2 at a voltage of 13 V, and the Commission Internationale de l’Eclairage （CIE） chromaticity coordinates are almost constant during a large voltage change of 6–12 V. Furthermore, a current efficiency of 15.3 cd/A at an illumination-relevant brightness of 1000 cd/m2 is obtained, which rolls off slightly to 13.0 cd/A at an ultra high brightness of 50000 cd/m2. We attribute this great performance to wisely selecting an appropriate spacer together with effectively utilizing the combinations of exciton-harvested orange-phosphorescence/blue-fluorescence in the device. Undoubtedly, this is one of the most exciting results in two-wavelength HWOLEDs up to now.

Very-High Color Rendering Index Hybrid White Organic Light-Emitting Diodes with Double Emitting Nanolayers

A very-high color rendering index white organic light-emitting diode(WOLED) based on a simple structure was successfully fabricated. The optimized device exhibits a maximum total efficiency of 13.1 and 5.4 lm/W at 1,000 cd/m2. A peak color rendering index of 90 and a relatively stable color during a wide range of luminance were obtained. In addition, it was demonstrated that the 4,40,400-tri(9-carbazoyl) triphenylamine host influenced strongly the performance of this WOLED.These results may be beneficial to the design of both material and device architecture for high-performance WOLED.

High color rendering index white organic light-emitting diode using levofloxacin as blue emitter

Levofloxacin （LOFX）, which is well-known as an antibiotic medicament, was shown to be useful as a 452-nm blue emitter for white organic light-emitting diodes （OLEDs）. In this paper, the fabricated white OLED contains a 452-nm blue emitting layer （thickness of 30 nm） with 1 wt% LOFX doped in CBP （4,4＇-bis（carbazol-9-yl）biphenyl） host and a 584-nm orange emitting layer （thickness of 10 nm） with 0.8 wt% DCJTB （4-（dicyanomethylene）-2-tert-butyl-6-（1,1,7,7- tetramethyljulolidin-4-yl-vinyl）-4H-pyran） doped in CBE which are separated by a 20-nm-thick buffer layer of TPBi （2,2＇,2＂-（benzene-1,3,5-triyl）-tri（1-phenyl-lH-benzimidazole）. A high color rendering index （CRI） of 84.5 and CIE chromaticity coordinates of （0.33, 0.32）, which is close to ideal white emission CIE （0.333, 0.333）, are obtained at a bias voltage of 14 V. Taking into account that LOFX is less expensive and the synthesis and purification technologies of LOFX are mature, these results indicate that blue fluorescence emitting LOFX is useful for applications to white OLEDs although the maximum current efficiency and luminance are not high. The present paper is expected to become a milestone to using medical drug materials for OLEDs.

Color-converted remote phosphor prototype of a multiwavelength excitable borosilicate glass for white light-emitting diodes

We report a unique red light-emitting Eu-doped borosilicate glass to convert color for warm white light-emitting diodes. This glass can be excited from 394 nm-peaked near ultraviolet light, 466 nm-peaked blue light, to 534 nm- peaked green light to emit the desired red light with an excellent transmission in the wavelength range of 400-700 nm which makes this glass suitable for color conversion without a great cost of luminous power loss. In particular, when assembling this glass for commercial white light-emitting diodes, the tested results show that the color rendering index is improved to 84 with a loss of luminous power by 12 percent at average, making this variety of glass promising for inorganic ＂remote-phosphor＂ color conversion.

White Organic Light-emitting Diodes with A Sr_2SiO_4:Eu^(3+) Color Conversion Layer

Abstract:Hybrid inorganic/organic white organic light emitting diodes(hybrid-WOLEDs)are fabricated by combi-ning the blue phosphorescent organic light emitting diodes(PHOLEDs)with red Sr2SiO4:Eu3+phosphor spin coatedas a color conversion layer(CCL)over the other side of glass substrate on the devices.The basic configuration of thePHOLEDs consists a host material,N,N'-dicarbazolyl-3,5-benzene(mCP)which doped with a blue phosphorescentiridium complexes iridium(Ⅲ)bis[(4,6-di-fluorophenyl)-pyridinato-N-C2'](FIrpic)to produce high efficient blueorganic light emitting diodes.The hybrid-WOLED shows maximum luminous efficiency of 22.1 cd/A,maximumpower efficiency of 11.26 lm/W,external quantum efficiency of 10.2%and CIE coordinates of(0.32,0.34).Mo-reover,the output spectra and CIE coordinates of the hybrid-WOLED have a small shift in different driving currentdensity,which demonstrate good color stability.

Color-Tunable Hybrid White Organic Light-Emitting Diodes with Double Interlayers

An efficient color-tunable hybrid white organic light-emitting diode is demonstrated with double interlayers of 2,7-bis(carbazol-9-yl)-9,9-ditoylfluo- rene/2-(diphenylphosphoryl) spiroflu-orene (DMFL-CBP/SPPO1) inserted between blue fluorescent and yellow phosphorescent-emitting layers, and exhibits Commission Internationale de l’Eclairage (CIE1931) ranging from warm white (0.4368, 0.4497) to cool white (0.2781, 0.2896) with driving current density from 0.2 to 40 mA/cm2. The recombination of singlet and the triplet excitons in blue fluores-cent-emitting layer and yellow phosphorescent-emitting layer, respectively, can be modulated by both the thickness of these double interlayers and the applied current densities.

Fabrication of High Color Rendering Index White Light Emitting Diodes from Gold Nanoclusters

We demonstrated gold nanoclusters as color tunable emissive light converters for the application of white light emitting diodes (WLEDs). A blue LED providing 460 nm to excite gold nanoclusters mixed with UV curable material generates broad bandwidth emission at the visible range. Increasing the amount of gold nanoclusters, the correlated color temperature of WLEDs tuned from cold white to warm white, and also results in the variation of color rendering index (CRI). The highest CRI in the experiment is 92.

Basic Color Terms “Black” and “White” Cognitive Semantic Analysis

Chinese Color Words two words have a higher degree turn and turn-grade class degree,they are "white"(white) and "black"(black),these two sets of words are generally located on human color perception of the system the top three,we believe that the typical basic color terms most likely to turn and turn-grade class,but different history,culture and other aspects of cognition,cross-grammatical category they are different order.Based on this,in English and Chinese Basic Color Terms "Black" and "White" Cognitive Semantic Analysis of the research topic,this in-depth study of this aspect of the study hope to be beneficial to help.

High efficient and high color rendering index white organic light-emitting diodes

We have fabricated high-efficient white organic light-emitting diodes （WOLEDs） using two types of electron transport materials with different electron mobility. The effect of the electron mobility on the device performance is discussed. In addition, to generate the desired white emission and high color rendering index, we perform the structure design of OLED, in which the functions of co-host of blue and green dopants on chromatic-stability are investigated. Experimental results find that the maximum color rendering index reaches as high as 91 at the voltage of 8 V.

Flexible white top-emitting organic light-emitting diode with a MoO_x roughness improvement layer

In this paper, an MoOx film is deposited on a polyethylene terephthalate （PET） substrate as a buffer layer to improve the surface roughness of the flexible PET substrate. With an optimized MoOx thickness of 100 nm, the surface roughness of the PET substrate can be reduced to a very small value of 0.273 nm （much less than 0.585 nm of the pure PET）. Flexible white top-emitting organic light-emitting diodes （TEOLEDs） with red and blue dual phosphorescent emitting layers are constructed based on a low-reflectivity Sm/Ag semi-transparent cathode. The flexible white emission exhibits the best luminance and current injection characteristics with the 100-nm-thick MoOx buffer layer and this result indicates that a smooth substrate is beneficial to the enhancement of device electrical and electroluminescence performances. However, the white TEOLED with a 50-nm-thick MoOx buffer layer exhibits a maximum current efficiency of 4.64 cd/A and a power efficiency of 1.9 lm/W, slightly higher than those with a 100-nm MoOx buffer layer, which is mainly due to an obvious intensity enhancement but limited current increases in 50-nm MoOx-based white TEOLED. The change amplitudes of the Commission International de l’Eclairage （CIE） chromaticity coordinates are less than （0.016, 0.005） for all devices in a wide luminance range over 100 cd/m2, indicating an excellent color stability in our white flexible TEOLEDs. Additionally, the flexible white TEOLED with an MoOx buffer layer shows excellent flexibility to withstand more than 500 bending times under a curvature radius of approximately 9 mm. Research demonstrates that it is mainly attributed to the high surface energy of the MoOx buffer layer, which is conducible to the improvement of the surface adhesion to the PET substrate and the Ag anode.

Regulating Charge and Exciton Distribution in High-Performance Hybrid White Organic Light-Emitting Diodes with n-Type Interlayer Switch

The interlayer(IL) plays a vital role in hybrid white organic light-emitting diodes(WOLEDs); however,only a negligible amount of attention has been given to n-type ILs. Herein, the n-type IL, for the first time,has been demonstrated to achieve a high efficiency, high color rendering index(CRI), and low voltage trade-off.The device exhibits a maximum total efficiency of 41.5 lm W^(-1), the highest among hybrid WOLEDs with n-type ILs. In addition, high CRIs(80–88) at practical luminances(C1000 cd m^(-2)) have been obtained, satisfying the demand for indoor lighting. Remarkably, a CRI of 88 is the highest among hybrid WOLEDs. Moreover, the device exhibits low voltages, with a turn-on voltage of only 2.5 V([1 cd m^(-2)), which is the lowest among hybrid WOLEDs. The intrinsic working mechanism of the device has also been explored; in particular, the role of n-type ILs in regulating the distribution of charges and excitons has been unveiled. The findings demonstrate that the introduction of n-type ILs is effective in developing high-performance hybrid WOLEDs.

Analysis of Using Ultraviolet Light to Test Color Mothball

Color mothball is a daily necessity in Southeast Asia. Mothball contained nearly 100% naphthalene or 100% p-dichlorobenzene. It was used to resist insects, mothproof and mildew with a special odor. In other words, the odor was thought unpleasant enough to drive animals away in repellent products. This research analyzed color mothball which was manufactured by C and N companies. The mothball was dyed with eight dyes and three essences of fragrance, respectively. The experiment of color fastness with UV-light test is to determine how much the color will fade, when it exposed to a known ultraviolet light source. In the last analysis, the experimental data from the spectrum of GC/MS described all kinds of structure on color mothball after 80 hours phototherapy treatment as shown in the content. This research reveals that color mothball can have better appearance and greater performance, to meet the requirements for customs and various applications.

Phosphor-free white light-emitting diodes

The multiple color-matching schemes that could improve the color rendering index for phosphor-free white LEDs are discussed. Then we review a few of the recent research directions for phosphor-free white LEDs, which include the development of monolithic GaN-based white LEDs and hybrid integrated GaN-based and A1GalnP-based white LEDs. These development paths will pave the way toward commercial application of phosphor-free white LEDs in the coming years.

凝聚剂组成对G-ABS高胶粉及ABS外观特性的影响

在使用凝聚剂从聚丁二烯与丙烯腈和苯乙烯的接枝共聚物(G-ABS)胶乳中回收G-ABS高胶粉的过程中,凝聚剂组成不但会改变高胶粉的粒径,还会对丙烯腈-丁二烯-苯乙烯三元共聚物(ABS)粒料的白度和色度稳定性造成影响。以冰乙酸/硫酸镁、硫酸/硫酸镁为凝聚剂,通过调整阳离子的配比,对比2组凝聚剂对G-ABS高胶粉和ABS外观特性的影响。结果表明:在确保凝聚浆液为酸性时,减少凝聚剂阳离子中H+占比,对粉料筛分粒径分布、氧化诱导时间没有明显影响,但ABS白度、热氧老化色度稳定性和粒料储存色度稳定性均有提升;与使用硫酸相比,使用冰乙酸能够显著提升ABS白度和热氧老化色度稳定性。

白三叶花色遗传规律及对光温的响应

为明确白三叶红花突变体花色性状的遗传规律,探究光温对花色表达的影响,以白三叶红花突变体和白花品种为材料进行杂交、回交、自交和测交试验,研究杂交后代花色性状分离规律,并分析不同温度和光照处理下白三叶突变体花色的色度差异。白三叶红花突变体与白花品种杂交F1代花瓣均显白色,突变体自交一代(S_(1))花瓣均显红色;F_(2)代和回交一代(BC_(1))花色分离符合孟德尔遗传规律,红花与白花比例分别为49:699和96:279,基本符合1:15和1:3的预期比例。相对于暖温环境(28℃8 h,34℃16 h),低温处理(12℃8 h,18℃16 h)显著降低花瓣亮度值(L值),红色度(a值)增加但差异不显著;温度骤降显著提高花瓣红色度,降低花瓣亮度。遮光2 d后突变体花瓣颜色由红转白,恢复光照1 d后又转为红色。白三叶红花突变体花色性状受双隐性基因控制,光是白三叶红花突变体花瓣颜色调控的关键因素。

NaYSiO_(4)∶Ce^(3+)蓝色荧光粉的发光性质及其在白光发光二极管上的应用

采用高温固相法合成了NaYSiO_(4)∶xCe^(3+)(0.01≤x≤0.05)系列蓝色荧光粉。NaYSiO_(4)∶xCe^(3+)荧光粉在250~360 nm之间的宽带吸收能与紫外LED芯片很好地匹配。NaYSiO_(4)∶xCe^(3+)荧光粉中存在多个Ce^(3+)离子荧光中心,且在紫外光激发下表现出峰值波长位于414 nm附近的宽带蓝光发射。NaYSiO_(4)∶0.02Ce^(3+)荧光粉在300~350 nm紫外光激发下量子效率在25%以上。NaYSiO_(4)∶0.02Ce^(3+)荧光粉表现出优良的化学稳定性,在水中浸泡14 d后荧光强度和量子效率几乎不变。将NaYSiO_(4)∶0.02Ce^(3+)蓝色荧光粉、商用(Sr,Ba)_2SiO_(4)∶Eu^(2+)绿色荧光粉和商用(Ca,Sr)AlSiN_(3)∶Eu^(2+)红色荧光粉涂覆于310 nm紫外LED芯片上制备得到了显色指数高达95的LED器件。当驱动电流从50 mA逐渐增大到300 mA时,制备的LED器件表现出稳定的暖白光发射,其色坐标几乎不变。上述结果说明,本研究报道的NaYSiO_(4)∶0.02Ce^(3+)蓝色荧光粉在紫外LED芯片驱动的白光发光二极管照明上有着潜在应用价值。

Image Correction Method of Color Line-Scan System

As the development of machine vision technology, the color line-scan system is widely applied in the on-line inspection. Due to the non-uniform gray scale and color distortion of the image acquired by the system, the image correction is needed to reduce the problem of image processing and the stability system. Based on reasons mentioned above, a method that using polynomial fitting to correct the image is presented to solve the problem in this paper. The method has been used in the automatic optical inspection of PCB, and has been proved to be effective. So this method will have a potential application to the development of the color line-scan machine vision system.

深色服装白墨直喷印花技术的研究

喷墨印花是具有发展潜力的新型印花技术之一,因深色服装印花困难,当前市场上深色服装常采用的喷墨印花为先丝网印白墨打底,再喷墨印花,工艺复杂,而深色服装白墨直喷印花先进技术可以代替。文中介绍了深色服装白墨直喷印花技术的应用现状和发展,阐述了白彩同出喷墨印花生产工艺流程。具体分析了印前分色原理、应用软件和性能要求,印前预处理目的、工艺处方和工艺方法,打印用白墨、彩墨的组成和物理性能指标,打印工艺类型、特点、难点和方法,印后烘干与固色工艺等,为深色服装白墨直喷印花生产提供参考方案。

白术清炒过程中颜色变化与5-羟甲基糠醛的相关性分析及拐点研究

目的:研究白术清炒过程中颜色变化与5-羟甲基糠醛(5-HMF)的相关性,并通过其炮制过程中各指标的动态变化分析炮制拐点。方法:清炒法炮制白术,运用薄层扫描仪、MATLAB软件评估白术生品及炮制品的颜色值,测定氧化值,HPLC法测定5-HMF含量,SPSS21.0软件分析颜色与5-HMF含量的相关性并建立回归模型。结果:相关性分析显示,色调H与亮度Ⅰ呈极显著正相关,与氧化值、5-HMF含量均呈极显著负相关;饱和度S与亮度Ⅰ呈显著负相关,与氧化值呈极显著正相关;亮度Ⅰ与氧化值、5-HMF含量均呈极显著负相关;氧化值与5-HMF含量呈极显著正相关。5-HMF含量与颜色值的回归模型为Y_((5-HMF))=24.928-43.398X_((H)),R^(2)=0.908,拟合度高,模型有效。结论:白术清炒过程中其颜色与5-HMF含量显著相关,依据其颜色变化预测炮制过程中5-HMF的含量具有可行性,并且依据各指标动态变化可分析炮制拐点,为白术清炒过程中炮制程度的判断提供参考依据。