效率增强的新型蓝色有机发光器件

使用一种新型空穴传输材料J003制备了不同结构、不同发光层厚度的两组蓝色发光器件,其结构为:ITO/CuPc/J003/JBEM:perylene/Al_q3/LiF/Al和ITO/CuPc/J003/JBEM:perylene/TPBi/Al_q3/LiF/Al,这里CuPc(Copper phthalocyanine)和LiF分别为空穴注入层(HIL)和电子注入层(EIL),J003为空穴传输层(HTL),JBEM(9,10-bis(3,5'-diaryl)phenylylanthracene)为发光层(EML),TPBj(1,3,5-tri(phenyl-2-benzimidazole)-benzene)为空穴阻挡层(HBL),Al_q3(tris(8-quinolinolato)aluminium complex)为电子传输层(ETL).两种结构中前者为无阻挡层的普通型结构,后者在发光层和电子传输层中加入了空穴阻挡层,是新型阻挡层结构.研究了空穴阻挡层的引入在不同厚度发光层时对器件发光性能的影响,结果表明,新型阻挡层结构能明显提高器件的亮度和效率,但依赖于发光层厚度,利用能级图分析了其中的原因.     

基于Si-rich SiNx/N-rich SiNy多层膜结构电致发光特性研究

利用等离子体增强化学气相沉积法制备了富硅氮化硅/富氮氮化硅多层膜,并以此氮化硅基多层膜作为有源层构建电致发光器件,在室温下观察到了较强的电致可见发光.在此基础上,研究多层膜结构中作为势垒层的富氮氮化硅层对器件电致发光性质的影响,实验结果表明通过改变势垒层的Si/N组分,调制其势垒高度,器件的电致发光效率可得到显著地提高. 关键词： 电致发光 多层膜 氮化硅     

基于Si-rich SiNx/N-rich SiNy多层膜结构电致发光特性研究

利用等离子体增强化学气相沉积法制备了富硅氮化硅/富氮氮化硅多层膜,并以此氮化硅基多层膜作为有源层构建电致发光器件,在室温下观察到了较强的电致可见发光.在此基础上,研究多层膜结构中作为势垒层的富氮氮化硅层对器件电致发光性质的影响,实验结果表明通过改变势垒层的Si/N组分,调制其势垒高度,器件的电致发光效率可得到显著地提高.     

同时掺杂磷光和荧光染料的白色有机电致发光器件性能研究

以磷光染料Ir(piq)₂(acac)作为发光掺杂剂,掺入空穴传输性主体材料NPB中得到红色发光层,荧光材料TBP掺入到主体CBP中作为蓝色发光层,制备了结构为ITO/NPB/NPB：Ir(piq)₂(acac)/CBP/CBP：TBPe/BCP/ALq/Mg：Ag的双发光层白色有机电致发光器件.其中ALq₃、未掺杂的NPB和CBP及BCP层分别作为电子传输层、空穴传输层和激子阻挡层.实验中通过调节发光层厚度及Ir(piq)_{2关键词： 磷光 激子阻挡层 有机电致发光}     

高效率和色稳定性的双超薄发光层的黄光有机电致发光器件

主要对rubrene黄光发光材料制作0.1nm厚度的超薄发光层的有机电致发光器件作了研究,并配合BCP空穴阻挡层探讨了对器件效率和色坐标稳定性的影响。双超薄rubrene发光层配合BCP空穴阻挡层的有机电致发光器件的性能得到了很好的改善,外加电压6V时,器件电流效率为6.35cd.A-1;外加电压10V时,器件发光亮度达到了7068cd.m-2。另外,在较大的外加电压驱动范围内,器件的色坐标一直保持在(0.49,0.49)。增加的发光效率和良好的色坐标稳定性主要是取决于空穴与电子的注入与输运平衡以及激子在超薄rubrene发光层中稳定性的复合平衡。     

基于Si-rich SiNx/N-rich SiNy多层膜结构的量子点构筑及发光特性

利用等离子体增强化学气相沉积法制备Si-rich SiN_x/N-rich SiN_y多层膜,分别使用热退火和激光辐照技术对多层膜进行退火,以构筑三维限制、尺寸可控、有序的硅纳米晶.实验结果表明,经退火后,纳米硅晶粒在Si-rich SiN_x子层内形成,其尺寸可由Si-rich SiN_x子层厚度调控.实验还发现,激光辐照技术相比于热退火能更有效地改善多层膜的微结构,提高多层膜的晶化率,以激光技术诱导晶化的Si-rich SiN_x/N-rich SiN_y多层膜作为有源层构建电致发光器件,在室温下观察到了增强的电致可见发光,并且发光效率较退火前提高了40%以上. 关键词： 氮化硅 多层膜 限制结晶 纳米晶硅     

稀土配合物与PVK共混体系发光特性及载流子复合区域转移的研究

合成了一种新型的铽钆共掺稀土配合物TbGd(BA)6(bipy)2,把它作为发光材料应用于有机电致发光中。文中摸索了器件优化条件,并讨论了TbGd(BA)6(bipy)2与PVK共混体系的发光机理和载流子复合区域的转移。稀土配合物的光致发光是由于外部直接激发及PVK到稀土配合物的能量传递。电致发光有两个途径,PVK到稀土配合物的能量传递及载流子的直接俘获。在双层器件中,发光区域随Alq3厚度变化,尤其是在高电压下,载流子复合区域移向Alq3一侧,而在增加BCP作为空穴阻挡层的多层器件中,载流子限制在发光层和空穴阻挡层的界面处复合,随着电场的增强,铽发光趋于饱和,而出现了高分子基质的发光。优化后,得到213 cd·m-2明亮的铽的绿色发光。     

应用交互叠层空穴传输层的高效铕配合物发光二极管

制备了铕配合物有机发光二极管(OLED),为了获得Eu(DBM),bath的特征发射,在器件中引入BCP作为空穴阻挡层。通过引入交互叠层的TPD／m-MTDATA作为空穴传输层,与传统异质结器件相比,最大发光效率及最大发光亮度都有明显提高。其最大发光效率在电流密度为2．8mA/cm^2时达到3cd／A,在电流密度为170mA/cm^2时器件达到最大亮度670cd／cm^2。对BCP空穴阻挡层及TPD／m-MTDATA交互叠层改善器件性能机理亦进行了讨论。     

纳米ZnO薄膜对有机电致发光器件性能的影响

由于有机电致发光器件(Organic light-emitting devices,OLEDs)的主动发光、高亮度等优点,在显示和照明领域有极大的应用前景。报道了纳米ZnO薄膜对这种发光器件性能的影响。在普通有机电致发光器件空穴传输层和发光层之间直接蒸镀一层纳米ZnO薄膜,当纳米ZnO薄膜的厚度为1nm时,器件的电流效率可达3.26cd/A,是没有纳米ZnO薄膜同类器件的1.24倍。适当厚度的纳米ZnO薄膜降低了发光层空穴的浓度,提高了电子和空穴的平衡,从而提高了器件的效率。     

21世纪的光学和光电子学讲座 第二讲 硅基发光材料和器件研究

硅基发光材料和器件是实现光电子集成的关键．文章评述了目前取得较大进展的几种主要硅基发光材料和器件的研究,包括掺饵硅,多孔硅,纳米硅以及Ｓｉ／ＳｉＯ２ 等超晶格结构材料．展望了这些不同硅基发光材料作为发光器件和在光电集成中的发展前景     

A comparison study of electroluminescence from Au/native oxide/p-Si and Au/porous Si diodes

Visible electroluminescence (EL) has been observed from a Au/native oxide/p-Si diode and has been studied in comparison with the EL from a Au/porous Si diode. Both diodes share similarities in current-voltage characteristics, EL spectra, and electrical input power dependence of integrated EL intensity. However, Au/porous Si exhibits quite strong photoluminescence (PL) while Au/native oxide/p-Si does not show any measurable PL. For the Au/native oxide/p-Si diode, when the native oxide layer was removed in 1% HF solution, no detectable EL has been observed. These experimental results indicate that the native oxide layer plays a key role in light emission from the Au/native oxide/p-Si diode, and show that the luminescence mechanism for Au/native oxide/p-Si diodes is similar to that for the Au/porous Si diode. This comparative study may aid in elucidation of the EL mechanism of porous silicon.     

Effect of MgZnO barrier layer on the UV emission of n-ZnO/p-Si heterojunction diodes

ZnO-based heterojunction light emitting diodes (LEDs) with MgZnO barrier layer had been fabricated on the p-Si substrate by metal-organic chemical vapor deposition (MOCVD) technology. The current-voltage (I-V) characteristics exhibited a typical p-n diode behavior. Both ultraviolet (UV) and visible emissions could be detected in the electroluminescence (EL) measurement. The result was compared with the EL spectrum of n-ZnO/p-Si heterojunction LED without MgZnO barrier layer. An improved light extraction efficiency by about 31% was realized owing to the current-blocking effect of MgZnO layer. The result indicated that MgZnO barrier layer can prevent the electrons as expected and realize electron-hole recombination in ZnO layer effectively.     

Electroluminescence from Si／SiO2 films deposited on p—Si substrates

The structure of Au/Si/SiO₂/p-Si has been fabricated using the magnetron sputtering technique. It has a very good rectifying behaviour. Visible electroluminescence (EL) has been observed from the Au/Si/SiO₂/p-Si structure at a forward bias of 5V or larger. A broad band with one peak around 650－660 nm appears in all the EL spectra of the structure. The effects of the thickness of the Si layer in the Si/SiO₂ films and of the input electrical power on EL spectra are studied systematically.     

Barrier height enhancement of metal/semiconductor contact by an enzyme biofilm interlayer

A metal/interlayer/semiconductor (Al/enzyme/p-Si) MIS device was fabricated using α-amylase enzyme as a thin biofilm interlayer. It was observed that the device showed an excellent rectifying behavior and the barrier height value of 0.78?eV for Al/α-amylase/p-Si was meaningfully larger than the one of 0.58?eV for conventional Al/p-Si metal/semiconductor (MS) contact. Enhancement of the interfacial potential barrier of Al/p-Si MS diode was realized using enzyme interlayer by influencing the space charge region of Si semiconductor. The electrical properties of the structure were executed by the help of current–voltage and capacitance–voltage measurements. The photovoltaic properties of the structure were executed under a solar simulator with AM1.5 global filter between 40 and 100?mW/cm² illumination conditions. It was also reported that the α-amylase enzyme produced from Bacillus licheniformis had a 3.65?eV band gap value obtained from optical method.     

A comparative study of electroluminescence from Ge／SiO2 and Si／SiO2 films

Ge/SiO_2 and Si/SiO_2 films were deposited using the two-target alternation magnetron sputtering technique. The Au/Ge/SiO_2/p-Si and Au/Si/SiO_2/p-Si structures were fabricated and their electroluminescence (EL) characteristics were comparatively studied. Both Au/Ge/SiO_2/p-Si and Au/Si/SiO_2/p-Si structures have rectifying property. All the EL spectra from the two types of the structure have peak positions around 650－660 nm. The EL mechanisms of the structures are discussed.     

Electroluminescence from nano-crystalline Si/ SiO2 structures embedded in pn junctions

Phosphorous-doped and boron-doped amorphous Si thin films as well as amorphous SiO₂/Si/ SiO₂ sandwiched structures were prepared in a plasma enhanced chemical vapor deposition system. Then, the p–i–n structures containing nano-crystalline Si/ SiO₂ sandwiched structures as the intrinsic layer were prepared in situ followed by thermal annealing. Electroluminescence spectra were measured at room temperature under forward bias, and it is found that the electroluminescence intensity is strongly influenced by the types of substrate. The turn-on voltages can be reduced to 3 V for samples prepared on heavily doped p-type Si (p⁺-Si) substrates and the corresponding electroluminescence intensity is more than two orders of magnitude stronger than that on lightly doped p-type Si (p-Si) and ITO glass substrates. The improvements of light emission can be ascribed to enhanced hole injection and the consequent recombination of electron–hole pairs in the luminescent nanocrystalline Si/ SiO₂ system.     

Fabrication of electrically contacted plasmonic Schottky nanoantennas on silicon

We fabricate Schottky contact photodetectors based on electrically contacted Au nanoantennas on p-Si for the plasmonic detection of sub-bandgap photons in the optical communications wavelength range. Based on a physical model for the internal photoemission of hot carriers, photons coupled onto the Au nanoantennas excite resonant plasmons, which decay into energetic "hot" holes emitted over the Schottky barrier at the Au/p-Si interface, resulting in a photocurrent. In our device, the active Schottky area consists of Au/p-Si contact and is very small, whereas the probing pad for external electrical interconnection is larger but consists of Au/Ti/p-Si contact having a comparatively higher Schottky barrier, thus producing negligible photo and dark currents.We describe fabrication that involves an electron-beam lithography step overlaid with photolithography. This highly compact component is very promising for applications in high-density Si photonics.     

a-SiC:H/pin势阱结构可见光电注入发光

本文提出一种新的a-SiC:H/pin势阱结构可见光注入式电致发光器件。设计制作了一组势阱结构和势垒结构对比的a-SiC:H/pin发光器件,其测试结果表明这种新的势阱结构器件发光特性较势垒结构器件有明显改进。本文还研究了该类器件在脉冲电流激励下的瞬态发光特性。