通过调控载流子复合和激子能量传递实现非掺杂WOLED的低效率滚降

基于磷光的白色有机发光二极管(WOLED)具有高效率和环境友好等优点,但仍然面临着制作过程复杂、高亮度下效率衰减的严峻挑战。在本文中,基于多个蓝色界面激基复合物并在其插入薄磷光层,制备了具有低效率滚降和无掺杂层的高效磷光体WOLED。我们提出的器件采用策略性激子管理,通过界面激基复合物对三重态能量进行限制。抑制了高亮度下激子浓度增加所引起的三重态–三重态湮灭(TTA)。同时采用PO-T2T/TPBi异质结有效地减少载流子捕获,有效地降低了载流子俘获所引起的三重态–极化子湮灭(TPA)。所得到的无掺杂的磷光WOLED的最大电流效率(CE)和功率效率(PE)为47.9 cd/A和50.1 lm/W,且3000 cd/m2亮度下的电流效率仍为40.0 cd/A,在无掺杂WOLED中达到了极低的效率滚降。我们的方法为克服无掺杂磷光体WOLED中三重态激子浓度猝灭和载流子俘获所引起的效率衰减提供了一条有效的途径。

基于界面激基复合物主体的WOLED器件光谱性能的研究

具有高显色指数(CRI)的白光有机发光二极管(WOLED)在照明应用上有着很大的优势。研究器件CRI随各色光强度的变化,以及提高器件的CRI,对OLED在照明应用上有着不小的帮助。在本文中我们提出了基于界面激基复合物主体系统,利用中间层(mCP)来调节激子能量的策略。在此基础上,我们利用蓝色界面激基复合物(mCP/PO-T2T)、黄色界面激基复合物(TAPC/PO-T2T)、绿色磷光材料(Ir(ppy)3)和红色磷光材料(Ir(piq)2(acac))制备了一系列优异性能的WOLED。研究了磷光材料掺杂的量和mCP中间层的厚度对器件性能的影响。结果显示,最大亮度和CRI分别为4862 cd/m2和95。驱动电压从4 V增加到7 V,CIE坐标偏移量仅为(0.044、0.009)。这种简单的结构为利用多种激基复合物实现高CRI和颜色稳定性提供了一种新的方法。

空穴阻挡中间层的加入对WOLEDs光谱稳定性的提高

制备了多层结构合成的白光有机电致发光器件(WOLEDs),通过在发光层中加入一层空穴阻挡层TPBi来提高器件的光谱稳定性。当TPBi厚度为2.5 nm时,在电压由8 V升高到12 V的过程中,CIE色坐标的变化量为(0.031,0.006)。器件的电流效率为24.7 cd/A,外部量子效率最大为8.2%。相对于没有加入中间层的器件,8 V电压下的色坐标由(0.435,0.472)变为(0.333,0.439)。实验结果表明,在发光层中添加中间层可以改变器件发光的色坐标并提升光谱的稳定性。

Soyinka’s Linguistic Legacy:A Comprehensive Review of“Soyinka’s Language”

Wole Soyinka,the pioneering African Nobel Prize laureate in Literature,occupies a vital role in the field of African Literature.In recognition of his paramount influence,Obioma Ofoego penned the book“Soyinka’s Language”,which focuses on Soyinka’s distinctive linguistic prowess and explores his ideological choice to write in English.Positioned against the backdrop of extensive postcolonial research on Wole Soyinka,“Soyinka’s Language”distinguishes itself through its comprehensive exploration of language as a central pillar of Soyinka’s literary oeuvre.This monograph provides readers with an in-depth understanding of how Soyinka’s ideological choice to write in English has shaped not only his own works but also the broader tapestry of African literature and postcolonial discourse.

The Study on the Relationship between Dynamic Balance Energy Distribution and Spectral Stability with Voltage Change in White Organic Light Emitting Diode

The stable spectrum can be obtained when the voltage changes, which is a necessary condition for the white organic light emitting diode (WOLED) device to be widely used in the field of solid-state lighting. However, with the increase of voltage, the movement of the recombination zone (RZ) is inevitable because the perfect bipolar host material is difficult to obtain, which will redistribute the energy in the light emitting layer (EML) and affect the stability of the spectrum. We fabricate a series of ternary hybrid WOLEDs with a simple structure by inserting ultra-thin PO-T2T into the blue exciplex (TCTA:TPBi) to form the green interface exciplex. Without considering the movement of RZ, device B2 realizes the dynamic balance energy distribution in EML and stable spectrum by controlling two processes of the Dexter energy transfer and exciton capture. By modifying the doping ratio of the host material, we also find that the broadened RZ is helpful to further improve the spectral stability of the device. When the voltage changes from 3 V to 7 V, the change range of color coordinates is only (0.026, 0.025).

The Influence of Energy Transfer on the Color Temperature Change in Color-Tunable Organic Light Emitting Diodes with Interface Exciplex

The color-tunable white organic light-emitting diode (CT-WOLED) with wide correlation color temperature (CCT) has many advantages in optimizing the artificial light source to adapt to the human physiological cycle. The research on the change trend of CCT and the law of extending the change range of CCT will help to further improve the performance of this kind of device. The present work fabricated a series of CT-WOLED devices with a simple structure, which are all composed of two ultra-thin phosphor layers (PO-01 and Flrpic) and a spacer interlayer. The yellow interface exciplex (TCTA/PO-T2T) formed between the spacer layer (PO-T2T) and transmission material (TCTA) in EML will decrease the CCT value at low voltage. The relationship between the energy transfer in EML and CCT change trend is investigated by adjusting the interface exciplexes and the thickness of the interlayer or the phosphor layer in devices A, B and C, respectively. The results demonstrate that a simple OLED device with an interlayer inserted between two ultra-thin phosphor layers can achieve a wider CCT span from 3359 K to 6451 K at voltage increases from 2.75 V to 8.25 V. .

NPB厚度对堆叠式白光OLED性能的影响

主要研究了NPB厚度对堆叠式白色有机电致发光器件性能的影响。实验制备了四组结构为ITO/2-TNATA(15 nm)/NPB(Tnm)/ADN(30 nm):TBPe(2%):DCJTB(1%)/Alq3(20 nm)/LiF(1 nm)/Al(100 nm)(其中T分别为15,30,35和40 nm)的OLED器件,比较了不同厚度情况下OLED器件的电致发光特性,结果表明:改变NPB(4,4-N,N-bis-N-1-naphthy1-N-pheny1-amino-bipheny1)的厚度能够明显提高器件的发光亮度和发光效率,并调节载流子复合区域的位置,有效提高载流子的注入效果。同时发光器件的颜色也可通过调节NPB层的厚度来改变,这种器件使用NPB作为空穴传输层显示出了色纯度高、亮度好、效率较高的白光发射,其具有CIE色坐标(x=0.301 6,y=0.338 5),最高亮度和最大发光效率分别达到14 020 cd/m2与2.94 lm/W。

光谱稳定的互补色双发光层高效混合白光OLED（英文）

利用两种颜色的发光层制备了光谱稳定的高效混合WOLED。其中蓝光发光层用14%质量分数的BNE掺杂在BePP_2中,橙光发光层用1%质量分数的Ir(bt)2(acac)掺杂在49.5%质量分数的NPB和49.5%质量分数的BePP_2组成的混合主体中。在不利用任何光耦合技术的条件下,器件在亮度为100 cd/m2时,功率效率可以达到39 lm/W;当亮度提高到1 000 cd/m^2时,效率仅发生轻微滚降至27.5 lm/W。器件的光谱稳定,亮度在1 000 cd/m^2和10 000 cd/m^2时,CIE坐标分别为(0.37,0.48)和(0.37,0.47)。良好的光谱稳定性归结于设计的双极性中间层平衡了其两侧激子的产生。

白光LED灯应用及发展

白光LED灯是LED的新生产品,在多个领域有广大的应用,将会成为主要的发光光源,其未来发展主要分为无机材料LED和有机材料LED(WOLED),尤其是有机材料LED,在化学和材料学上发展的基础上,更是具有高可靠性、高功率性和价格低廉等特点。

White organic light-emitting device with both phosphorescent and fluorescent emissive layers

This paper reports the fabrication of novel white organic light-emitting device（WOLED） by using a high efficiency blue fluorescent dye N-（4-（（E）-2-（6-（（E）-4-（diphenylamino）styryl）naphthalen-2-yl）vinyl）phenyl）oN- phenylbenzenamine （N-BDAVBi） and a red phosphoresecent dye bis （1-（phenyl） isoquinoline） iridium （III） acetylanetonate （Ir（piq）2（acac））. The configuration of the device was ITO/PVK：TPD/CBP： N-BDAVBi /CBP/ BALq： Ir（piq）2（acac）/BCP/Alq3/LiF：AL. By adjusting the proportion of the dopants （N-BDAVBi, Ir（piq）2（acac）） in the light-emitting layer, white light with Commission Internationale de l＇Eclairage （CIE） coordinates of （0.35, 0.35） and a maximum luminance of 25350cd/m2 were obtained external quantum and current efficiency of 6.78% and between the two light-emitting layers and using BCP at an applied voltage of 22V. The WOLED exhibits maximum 12cd/A respectively. By placing an undoped spacer CBP layer as hole blocking layer, the colour stabilization slightly changed when the driving voltage increased from 6 to 22 V.

OLED技术稳步前行

FPD（平板显示器）市场竞争日趋激烈，LCD（液晶显示器）逐渐替代CRT（阴极射线管）占据主要地位，其它众多的平板显示技术，诸如PDP（等离子显示屏）、OLED（有机发光二极管）等依据自身的优点，纷纷扩大销售量，分享平板显示器市场份额。

白色OLED

随着单色OLED的性能逐渐成熟．白光OLED（whiteorganiclight-emittingdiodes．WOLED）作为一种新型的固态光源，在照明和平板显示背光源等方面展现了良好的应用前景，已经吸引了人们越来越多的注意。1994年，日本的Kido等人制备了第一块WOLED，任器件中同时包含红光、绿光和蓝光发射，

OLED的最新消息

美国通用显示器公司（Universal Display Corporation，缩写UDC）成功地得到全荧光白有机发光二极管（WOLED^TM），在表面亮度是1000cd／m^2时的光效达45 lm／w，该器件使用更低的驱动工作电压，使耦合效率从20％提高到40％，同时引入了高效的荧光剂使流过WOLED的电流都发光。

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.

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.

2015年下半年OLED材料需求激增三倍

根据IHS发布的报告显示，随着LGDisplay增加了白色有机发光二极管（WOLED）电视面板的产量，从2015年下半年开始，主动矩阵有机发光二极管（AMOLED）材料的消耗将激增。2015年上半年，WOLED有机材料市场规模达5800万美元，而到下半年，WOLED市场将激增三倍。

中国有望再上5条第6代柔性AMOLED生产线

IHS Markit最新报告显示，全球AM OLED产能将从2017年的1190万平方米上升到2022年的5010万平方米，实现322％的增长。该数字包括RGB OLED的容量以及主要用于电视的WOLED（也称为白色OLED）的容量。在这两个板块中，RGB OLED占有较大的市场份额，产能将从2017年的890万平方米增加到2022年的3190万平方米。

2015年下半年OLED面板材料市场需求激增三倍

根据IHS发布的报告显示，随着LGDisplay增加了白色有机发光二极管（WOLED）电视面板的产量，从2015年下半年开始，主动矩阵有机发光二极管（AMOLED）材料的消耗将激增。2015年上半年，WOLED有机材料市场规模达5800万美元，而到下半年，WOLED市场将激增三倍。2014年到2019年，WOLED有机材料市场的复合年增长率（CAGR）为79％。

40 Years of Soyinka’s Drama in China

The translation,introduction and research on Soyinka and his plays in China has lasted for 40 years.It could be roughly divided into three stages:From 1979 to 1986,Chinese only did some simple introduction to Soyinka’s life and creation.After Soyinka became a Nobel laureate,Chinese translators and critics began to pay more attention to his work and devoted a lot of research work.However,Since 2000,China has made great achievements in the introduction,translation and research of Soyinka and his dramas.The spread of Soyinka’s Plays in China experienced a process ranging from unfamiliarity,coldness and understanding difficulties to familiarity,attention and further exploration.For Chinese readers,Soyinka is a famous Nobel laureate,a post-colonial writer,and an African national writer.Chinese researchers generally believe that Soyinka’s plays are influenced by both African and European cultures,and have distinct religious features,national spirits,post-colonialism,and other basic characteristics.

加入激子阻挡层增强白色有机发光器件效率

通过在发光层(EBL)与电子注入层之间增加激子阻挡层(EBL)制备了新型白色有机发光器件(WOLED)。有EBL的新型器件效率和亮度均比传统结构器件高50%,在电流密度为4 mA/cm2时效率达到3.42 cd/A,最大亮度为11 000 cd/m2(16 V),色坐标为x=0.34、y=0.36;而具有相同EBL厚度的传统结构器件,在电流密度为4 mA/cm2时效率为2.15 cd/A,最大亮度为6 259 cd/m2(16 V)。效率的提高是由于EBL的限制作用而提高了激子浓度。测量了器件的效率与电流密度关系,随电流密度增加电流效率的衰减缓慢,说明短寿命红色搀杂剂的激子-激子湮灭很弱。