Research on flexible silver nanowire electrode for organic light-emitting devices

By spin-coating silver nanowires(AgNWs) and polymethyl methacrylate(PMMA), applying pressure imprint and plasma treatment, we obtained flat Ag NW thin film with a sheet resistance of 20 Ω/sq and a transmittance of 78% at 550 nm with low surface roughness. No significant change in sheet resistance was observed after cyclic bending(bending radius is 5 mm) test and tape test. After 1 000 bending tests, the change rate of sheet resistance was only 8.3%. The organic light-emitting devices(OLEDs) were prepared by using such Ag NW electrodes and a maximum brightness of 5 090 cd/m² was obtained. Compared with the Ag NWs electrode without any treatment, the present Ag NW electrodes have lower sheet resistance and better hole injection. Our results show spin-coated with flat layers, embossed and plasma-treated Ag NW electrodes are suitable for manufacturing flexible organic optoelectronic devices.     

Research on the impact of spin coating silver nano clusters on the performance of OLED devices

To achieve uniform distribution of silver nano clusters (SNCs) on substrate and reveal its effect on the performance of organic light-emitting diode (OLED), the SNCs incorporated OLED was fabricated and SNCs were coated by multi-step spin coating. Compared with the device without SNCs film, the brightness and current efficiency of the OLED devices with SNCs film were highly raised. The enhancement is attributed to SNCs induced local surface plasmon (LSP) oscillation, which can increase the radiative rate of excitons on Alq₃ molecules.     

基于单片机的全彩OLED静态显示驱动接口电路

针对奇晶公司生产的CMEL CO283QGLD-T型OLED显示模块的特性,以宏晶科技的STC11L60XE单片机为主控制器,进行OLED显示模块与单片机在SPI模式下的硬件接口设计和软件设计,并实现了分辨率为240×320的全彩图片静态显示。所设计的OLED驱动电路具有通用性,且可显示多种测试图片用于中小尺寸OLED的显示性能测试和评定。     

有机酸修饰ITO对OLED器件性能的影响

分别采用二氯苯氧乙酸和溴乙酸对ITO表面进行修饰,研究其对OLED器件(ITO/PVK/ FIrPic:SimCP/TPBi/LiF/Al)性能的影响.结果显示,相较于未修饰的器件,采用二氯苯氧乙酸修饰后的器件最大亮度由673.4 cd/m2提升至1 875.2 cd/m2,同时器件的启亮电压由6.2V降至5.3V.研究发现,有机酸处理能够改变ITO的表面能和功函数,一方面改变ITO和后续膜层的接触性能,影响后续膜层的成膜;另一方面也可以有效减少ITO与有机层间的势垒,提升载流子注入.这种用有机酸修饰ITO阳极的方法工艺简单,能有效降低空穴注入势垒,优化ITO和有机层的接触性能,对器件性能的提升起到一定的促进作用.     

两步溶液法制备亚微米ZnO棒阵列及其退火后的发光

通过改变溶液浓度、酸碱度等生长条件,用两步化学溶液沉积法在玻璃衬底上制备出有序排列的亚微米级ZnO棒阵列,棒的截面呈正六边形,直径约为200~500nm。测量了样品的XRD谱和扫描电镜像,证明这些样品都是六方纤锌矿结构的ZnO单晶,且以[002]方向择优生长。将样品退火前后的PL光谱进行比较分析,发现退火后样品的发射光谱中紫外峰消失而长波段的红色发光峰红移并且增强(峰位由630nm左右移到720nm),而其激发光谱中的室温激子激发峰也增强。当退火时间增加到6h后,出现了由430nm的蓝峰和505nm绿峰组成的宽谱带蓝绿色发射。并对发光机理进行了讨论。     

可调谐手性结构光场的产生及调控

提出一种环形相位构造方法,并通过实验产生了一种可调谐手性结构光场。在螺旋相位的基础上引入径向相位与等相相位形成环形子相位,在平面波上加载该相位产生单环手性结构光场。进一步利用相位叠加原理,组合多个不同环形子相位构成一个环形相位,进而利用其调控产生多环形手性结构光场。研究发现,通过控制拓扑荷数、等相位因子、径向偏移因子,能够灵活控制螺旋强度瓣叶的数量以及手性方向。此外,通过引入等相位梯度实现了光场的动态旋转。所构建的可调谐手性结构光场有益于手性结构微加工,在光学微操纵及光学通信领域也有较大的潜在应用价值。     

一种基于FPGA的OLED显示系统

针对LCD显示屏温度适应性差、可视角度小、LCD的通用驱动电路实现的对比度较低等缺点,采用OLED作为显示器件,设计并实现了一种使用FPGA驱动OLED的显示系统。采用PIC16F690单片机作为微处理器控制整机时序,利用FPGA进行视频信号处理,完成格式转换、色空间处理以及隔行转逐行操作,最终实现驱动显示。系统的测试结果表明,该方案不仅能显著提高画面对比度,而且能稳定显示监控图像,为后继功能的拓展提供了平台。     

MoO3作空穴注入层的绿光有机电致发光器件制备及其性能研究

用真空热蒸镀的方法制备了绿光有机电致发光器件,并对其工艺流程进行了详细的描述。器件结构为ITO/MoO3(xnm)/N,N′-diphenyl-N,N′-bis(1-naphthyl)-(1,18-biphenyl)-4,4-diamine(NPB)(40nm)/tris(8-hydroxyquinoline)aluminum(Alq3)(60nm)/LiF(1nm)/Al(150nm),其中x=0,5nm。实验中,对ITO基片进行氧等离子体表面处理,能够有效减小ITO表面的接触角。通过对器件的光电性能测试,研究了MoO3作空穴注入层对有机电致发光器件性能的影响。实验结果表明,空穴注入层MoO3的最高占据分子轨道(HOMO)能级较好的与ITO功函数匹配,降低了空穴注入势垒,提高了器件的发光亮度和效率。当外加电压小于10V时,器件的电流密度随外加电压的增加而增加,但变化不明显;当外加电压大于10V时,器件的电流密度明显增强,发光色度几乎不随驱动电压的改变而改变,色坐标稳定在(0.36,0.55)附近。     

Transparent conductive PVP/AgNWs films for flexible organic light emitting diodes by spraying method

In this study, a simple spraying method is used to prepare the transparent conductive films (TCFs) based on Ag nanowires (AgNWs). Polyvinylpyrrolidone (PVP) is introduced to modify the interface of substrate. The transmittance and bending performance are improved by optimizing the number of spraying times and the solution concentration and controlling the annealing time. The spraying times of 20, the concentration of 2 mg/mL and the annealing time of 10 min are chosen to fabricate the PVP/AgNWs films. The transmittance of PVP/AgNWs films is 53.4%—67.9% at 380—780 nm, and the sheet resistance is 30 Ω/□ which is equivalent to that of commercial indium tin oxide (ITO). During cyclic bending tests to 500 cycles with bending radius of 5 mm, the changes of resistivity are negligible. The performance of PVP/AgNW transparent electrodes has little change after being exposed to the normal environment for 1 000 h. The adhesion to polymeric substrate and the ability to endure bending stress in AgNWs network films are both significantly improved by introducing PVP. Spraying method makes AgNWs form a stratified structure on large-area polymer substrates, and the vacuum annealing method is used to weld the AgNWs together at junctions and substrates, which can improve the electrical conductivity. The experimental results indicate that PVP/AgNW transparent electrodes can be used as transparent conductive electrodes in flexible organic light emitting diodes (OLEDs).     

Achieving high-performance phosphorescent organic light-emitting diodes using thermally activated delayed fluorescence with low concentration

We fabricated phosphorescent organic light-emitting diodes (PhOLEDs) using thermally activated delayed fluorescence (TADF) material 10,10''-(4,4''-sulfonylbis(4,1-phenylene)) bis(9,9-dimethyl-9,10-dihydroacridine) (DMAC-DPS) with low concentration, which showed better performance compared with 1,3-bis(carbazole-9-yl) benzene (mCP) based devices. When the concentration of DMAC-DPS was 1wt%, the driving voltage of the device was only 3.3 V at 1 000 cd/m2, and the efficiency and lifetime of the device were effectively improved compared with those of mCP based devices. The result indicated that DMAC-DPS could effectively improve the performance of phosphorescent devices. We believe that the better device performance can be attributed to the optimization of the energy transfer process in the emitter layer and lifetime of triplet excitons by DMAC-DPS. The study may provide a simple and effective strategy to achieve high-performance OLEDs.