Investigation of large-area OLED devices with various grid geometries

Luminance homogeneity is an important aspect for large-area (>1 cm²) organic light emitting diodes (OLED). Especially, high sheet resistances of transparent contacts lead to a significant brightness inhomogeneity caused by a drop of local potential difference. Therefore the implementation of thin low-resistance metallic grids onto transparent contacts is a crucial development aspect for large-area OLED design. We develop a finite-element electro-optical simulation for OLED using grid structures to optimize geometry, thickness and width of grid elements. We find an exponential relationship between luminance homogeneity and grid material volume, which leads to limitations of minimal grid line width and maximal emissive area for efficient development of large-area OLED.     

Mechanical modeling of flexible OLED devices

General expressions are deduced for the stresses developed in the individual thin layers of a multi-layer structure as a result of bending to a specified radius. These are appropriate for analysing flexible organic light emitting diode (FOLED) devices on flexible substrates. Residual stress (caused internally by temperature change and differential thermal expansion) after material deposition and return to ambient temperatures is not considered. The reduced elastic modulus of the typical small molecule OLED materials: N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)benzidine (NPD) and tris-(8-hydroxyquinoline)aluminum (Alq₃) are measured as thin-films using nano-indentation techniques. A conventional device: polyethylene terephthalate (PET)/Buffer layer (BL)/ITO/OLED/Al is considered from a modeling standpoint, as a preliminary to actual fabrication and subsequent comparative testing of OLED performance on rigid and flexible supports.     

Functionalized terfluorene for solution-processed high efficiency blue fluorescence OLED and electrophosphorescent devices

A new multifunctional blue-emitting terfluorene derivative (TFDPA) featured with triphenylamine groups for hole-transportation and long alkyl chains for solution processability on the conjugation inert bridge centers was reported. TFDPA can give homogeneous thin film by solution process and exhibits high hole mobility (μ_h ≈ 10^?3 cm² V^?1 s^?1) and suitable HOMO for hole injection. Particularly, TFDPA performs efficient deep-blue emission with high quantum yield (～100% in solution, 43% in thin film) and suitable triplet energy (E_T = 2.28 eV), making solution-processed OLED devices of using TFDPA as blue emitter and as host for iridium-containing phosphorescent dopants feasible. The solution-processed nondoped blue OLED device gives saturated deep-blue electroluminescence [CIE = (0.17, 0.07)] with EQE of 2.7%. TFDPA-hosted electrophosphorescent devices performed with EQE of 6.5% for yellow [(Bt)₂Ir(acac)], 9.3% of orange [Ir(2–phq)₃], and 6.9% of red [(Mpq)₂Ir(acac)], respectively. In addition, with careful control on the doping concentration of [(Bt)₂Ir(acac)], a solution-processed fluorescence–phosphorescence hybrided two-color-based WOLED with EQE of 3.6% and CIE coordinate of (0.38, 0.33) was successfully achieved.     

OLED技术及柔性OLED性能、缺陷的研究

OLED凭借其在厚度、视角以及在发光效率等方面的优势成为目前平板显示技术开发的重点。首先简单介绍了OLED的结构、发光原理、驱动电路、发光材料等基本概念。重点针对柔性OLED,阐述了它的优点、缺陷,并进一步对其性能的改善做了相关研究。     

Low-temperature conformal vacuum deposition of OLED devices using close-space sublimation

Close-space sublimation (CSS) has been demonstrated as an alternative vacuum deposition technique for fabricating organic light-emitting diodes (OLEDs). CSS utilizes a planar donor plate pre-coated with organic thin films as an area source to rapidly transfer the donor film to a device substrate at temperatures below 200 °C. CSS is also conformal and capable of depositing on odd-shaped substrates using flexible donor media. The evaporation behaviors of organic donor films under CSS were fully characterized using model OLED materials and CSS-deposited films exhibited comparable device performances in an OLED stack to films deposited by conventional point sources. The low temperature and conformal nature of CSS, along with its high material utilization and short process time, make it a promising method for fabricating flexible OLED displays.     

OLED技术的颠覆性创新突破

有源有机发光二极管显示器（AMOLED）在显示和照明领域的潜在颠覆性创新优势已经逐渐被人们所认识。预计AMOLED将带来一次产业创新革命。     

有机电致发光的研究及进展

介绍有机电致发光器件的优点、结构及发光机理，评价有机电致发光器件的一些主要参数。说明OLED是一种很有前途的显示技术。     

Blue-hazard free candlelight-style tandem organic light-emitting diode

Long exposure to intensive blue light may damage retina and suppress, at night, melatonin secretion. To devise a blue hazard-free light source with a long lifetime, we demonstrated here a tandem organic light-emitting diode (OLED) with candlelight-style emission, especially via the use of all commercially-available materials. The resultant device shows a color temperature of 1500 K, significantly lower than the 1800 K of oil lamps, 1900 K of candles and 2500 K of incandescent bulbs. It permits, at 100 lx, a retinal exposure-limit of 12 h, while merely 5 min for the 6000 K cold-white LED or CFL. Notably, it is 15 times more human eye-friendly and 30 % more melatonin generation-friendly than the candle. It shows a lifetime of 40,000 h at 1000 cd per meter square, which is about 20,000 times that of a candle and 40 times that of an incandescent bulb. It is 65 times more energy-saving as comparing with candles. Commercially viable human-friendly lighting can be expected in the near future to safeguard human health.     

OLED显示的灰度控制

阐述信息显示中实现灰度显示的基本原理。根据有机发光二极管的特性，从电气灰度调制、空间灰度调制及时间灰度调制三方面列举了当前有机电致发光器件实现灰度级显示的主要方法，并分析和比较了每种方法的工作机理和应用特点，在此基础上提出了利用可编程模拟器件控制灰度级的新想法。     

OLED技术与市场展望

OLED属于一种崭新的显示器件，它将会对未来的图象显示技术带来无法估量的冲击力！OLED是最有发展前景的显示器件之一，并且将会成为平板显示领域中的一种主流技术，本文阐述OLED诉应用领域、市场前景及发展趋势。     

有机电致发光产品的研发现状

有机电致发光器件(OLED)具有驱动电压低、主动发光等优势,在平板显示领域引起了广泛的关注。本文介绍了近年来有机电致发光产品的研发状况,并展望了OLED的商业前景。     

玻璃后盖对有机电致发光器件封装性能的影响

实验采用玻璃湿法腐蚀凹槽制备了用于有机电致发光器件封装的玻璃后盖,并分析了氢氟酸浓度、温度、超声和反应物对玻璃刻蚀厚度和玻璃表面平整度的影响,得到了一种简单制备玻璃盖的工艺方法:在氢氟酸浓度为40%,在超声波清洗器中进行玻璃的腐蚀,腐蚀时间为15min,在腐蚀过程中间隔一定时间冲洗反应物后可以得到厚度为0.177mm,表面平整的玻璃封装盖,符合有机电致发光器件的封装要求。使用此方法制备的封装盖在氮气环境下将有机电致发光器件进行封装,可以减缓器件亮度的衰减。     

OLED显示设计与实现

介绍了OLED器件的功能、特性、控制逻辑、读写时序等.以一款新型的OLED器件VGG12864K作为显示终端,用嵌入式MCU开发的显示系统.论述了设计方法和设计过程中遇到的实际问题及解决的办法.如电路设计、软件编程、汉字显示实现等.     

Accurate optical simulation method of tandem organic light-emitting diode with consideration of Purcell effect

In this paper, we report an accurate optical calculation method of tandem organic light-emitting diode (OLED) with consideration of Purcell effect. Using the normal reported method, there are some discrepancies between calculation and experimental external quantum efficiencies. To improve such discrepancies, we considered Purcell effect in optical calculation method. This improved calculation with Purcell effect were well matched with experimental results. Additionally, we measured exciton lifetime to identify the validity of Purcell factor which was applied to calculation. Through this measurement, we identified theoretical calculation is well matched with experimental tendency. Thus, this calculation can be more useful in tandem OLED applications.     

Alq3厚度以及沉积速率对OLED性能的影响

以ITO为透明电极，NPB为空穴传输层，Alq3为发光层，制备出ITO／NPB／Alq3／LiF／Al结构的有机电致发光显示器。通过比较Alq3发光层厚度以及沉积速率对OLED的亮度、发光效率的影响，确定了Alq3层的厚度为65nm，沉积速率为0．3nm／s，得到起亮电压为3．01V、发光亮度为12800cd／m^2、发光效率达到4．421cd／A的器件，并对其影响因素进行了分析。     

Synthesis and luminescence properties of lithium,zinc and scandium 1-(2-pyridyl)naphtholates

1-(2-Pyridyl)naphth-2-ol (pynH) was synthesized from 2-bromopyridine and 1-bromo-2-hydroxynaphthalene and structurally characterized. This ligand and the known 2-(2-pyridyl)phenol (ppH) ligand were reacted with LiN(SiMe₃)₂, ZnEt₂ and Sc[N(SiMe₃)₂]₃ to prepare the new luminescent complexes Li(pp), Li(pyn), Zn(pyn)₂, Sc(pp)₃, Sc(pyn)₃ and known Zn(pp)₂. Photoluminescent (PL) spectra of the compounds contained a single broad band with a maximum at 447–473 nm. The OLED devices with a configuration of ITO/TPD/complex/Bath/Yb gave blue–green emission. The emission spectra of these devices resembled the PL spectra; however, the bands of electroluminescence (EL) were shifted 20–40 nm to the long-wavelength side. A maximum current efficiency 15.3 cd/A and a power efficiency 8.12 lm/W at 100 cd/m² were measured for the device with the zinc luminophore Zn(pp)₂, whereas the highest luminance of 8300 cd/m² at 22.5 V was observed with the device with the scandium complex Sc(pp)₃. DFT calculations showed that the latter complex exhibited the lowest HOMO and the highest LUMO energy levels compared with the other investigated compounds. The calculated trends with respect to the influence of the metal and the ligand on the LUMO–HOMO gap agree well with the shifts of the electronic transitions observed in the PL spectra of the complexes.     

OLED点阵驱动电路设计及OLED驱动特性研究

设计了一种方便测试OLED显示屏特性的驱动电路。用此驱动电路研究了与驱动方式相关的(OLED显示屏特性即“串扰”、老化、击穿等，观测到与OLED“形成过程”相对应的“恢复过程”。实验结果表明．通过对驱动电路采取适当的措施，能够减轻“串扰”和击穿对显示屏造成的影响，并延长显示屏的使用寿命。     

小分子OLED器件的制作

介绍了小分子OLED器件的基本结构和制作设备,制作了两种Alq_3基的小分子OLED器件,器件的结构分别为ITO/NPB(400)/Alq_3(300)/Al和ITO/NPB(400)/Alq_3(300)/LiF/Al,讨论了Al阴极中有无LiF对器件性能的影响,包括开启电压以及电流密度等参数。     

平板显示器中的OLED

随着最新平板显示技术的大量涌现和不断完善．使得平板显示的应用和市场进一步向难以预测的多元化方向发展。目前，由于OLED技术的日臻成熟和快速产业化．使得原有的平板显示的均衡将被打破。文章从技术、器件性能、应用和市场前景方面着重分析同OLED可能发生竞争的主要对手LCD(液晶显示器)与OLED的相应情况．并对平板显示技术的发展进行了分析预测。     

中国OLED相关专利趋势分析

有机发光二极管(Organic Light Emitting Diode,OLED)由于具备无需背光源、能耗低、亮度高、轻薄、抗震、环保等特点,因此其发展受到了国内外企业的广泛关注,OLED已成为显示技术领域中第三代显示器件的主力军.以近二十年OLED相关技术领域的中国专利申请为样本数据,从申请量、申请人分布、主要应用领域等方面分析了OLED相关技术在中国的专利布局情况.