利用多阱结构改善有机电致发光器件效率

将N,N'-bis-(1-naphthy1)-N,N'-dipheny-1,1'bipheny1 4,4'-diamine(NPB)与bathocuproine(BCP)2种材料以交叠沉积方式组成一种周期性结构作为空穴注入层,制备了结构为ITO/[NPB/BCP]n/AlQ/LiF/Al的有机电致发光器件(OLED).通过改变空穴注入层阱状结构的重复周期数n,可改变载流子复合区域,进而获得近白光和绿光发射.由于该结构能获得更好的载流子注入平衡,具有交叠结构空穴注入层的近白光器件在15 V时亮度达到3 433.8 cd/m2,在电流密度为60.9 mA/cm2时最大发光效率为2.26 cd/A.当周期数n大于3时得到绿光发射,与单空穴注入层ITO/NPB/AlQ/LiF/Al器件相比,交叠空穴注入层可将器件的最大亮度由2 512.8 cd/m2提高到866 1.0 cd/m2,最大亮度效率在20 mA/cm2时达到4.94 cd/A.     

Generalized Uncertainty Principle and Black Hole Entropy of Higher-Dimensional de Sitter Spacetime

Recently, there has been much attention devoted to resolving the quantum corrections to the Bekenstein-- Hawking black hole entropy. In particular, many researchers have expressed a vested interest in the coetticient of the logarithmic term of the black hole entropy correction term. In this paper, we calculate the correction value of the black hole entropy by utilizing the generalized uncertainty prlnciple and obtain the correction term caused by the generalized uncertainty principle. Because in our calculation we think that the Bekenstein-Hawking area theorem is still valid after considering the generalized uncertainty principle, we derive that the coefficient of the logarithmic term of the black hole entropy correction term is positive. This result is different from the known result at present. Our method is valid not only for four-dimensional spacetimes but also for higher-dimensional spacetimes. In the whole process, the physics idea is clear and calculation is simple. It offers a new way for studying the entropy correction of the complicated spacetime.     

Poly(3,4‐ethylenedioxythiophene) Derived from Poly(ionic liquid) for the Use as Hole‐Injecting Material in Organic Light‐Emitting Diodes

We report that poly(3,4‐ethylenedioxythiophene) derived from poly(ionic liquid) (PEDOT:PIL) constitutes a unique polymeric hole‐injecting material capable of improving device lifetime in organic light‐emitting diodes (OLEDs). Imidazolium‐based poly(ionic liquid)s were engineered to impart non‐acidic and non‐aqueous properties to PEDOT without compromising any other properties of PEDOT. A fluorescent OLED was fabricated using PEDOT:PIL as a hole‐injection layer and subjected to a performance evaluation test. In comparison with a control device using a conventional PEDOT‐based material, the device with PEDOT:PIL was found to achieve a significant improvement in terms of device lifetime. This improvement was attributed to a lower indium content in the PEDOT:PIL layer, which can be also interpreted as the effective protection characteristics of PEDOT:PIL for indium extraction from the electrodes.

     

激光治疗孔源性局限性视网膜浅脱离的疗效分析

目的本文回顾性总结了1993年6月～2000年5月来我院治疗的孔源性局限性视网膜浅脱离眼资料,并进行疗效分析。方法激光前详细检查眼底,记录视网膜裂孔的位置、形态和大小及视网膜脱离的范围,采用氩离子激光器作激光光凝。激光后每周随访眼底,光凝随着视网膜脱离范围缩小向裂孔方向推进,直至达裂孔边缘,完全封闭裂孔。结果马蹄形裂孔的局限性视网膜浅脱离发生率(26.2％)显著高于圆形裂孔(18.8％);本组资料局限性视网膜浅脱离眼共88只眼,激光治疗有效67只眼,有效率76.14％,其中颞下象限的局限性网脱的治愈率最低(37.15％)积液范围≤2PD治愈率为97.87％,≤3PD为92.42％,＞3PD则疗效显著下降,仅为27.27％,可见积液范围大小对治疗效果有非常显著影响;积液范围≥3PD者,各象限的失败率均高于60％,平均69.57％。结论激光治疗局限性视网膜浅脱离是一种操作简便、疗效显著的临床非手术治疗方法,疗效与裂孔的形态、位置、视网膜下积液范围的大小密切相关。     

印制电路板通孔的电镀技术

印制板通孔的金属化是一个极其复杂的过程,它涉及到去残渣、活化、化学镀铜和电镀铜,为了得到品质优良的产品,必须严格控制每一项操作。本文通过对生产现场易出现的问题,提出了对上述各工序管理的注意点。     

Synthesis and characterization of alternating copolymers containing triphenylamine as hole‐transporting units

A series of light‐emitting poly(p‐phenylene vinylene)s with triphenylamine units as hole‐transporting moieties in the main chain were synthesized via Wittig condensation in good yields. The newly formed vinylene double bonds possessed a trans configuration, which was confirmed by Fourier transform infrared and NMR spectroscopy. The high glass‐transition temperature (83–155 °C) and high decomposition temperature (>300 °C) suggested that the resulting copolymers possessed high thermal stability. These copolymers, especially TAAPV1, possessed a high weight‐average molecular weight (47,144) and a low polydispersity index (1.55). All the copolymers could be dissolved in common organic solvents, such as tetrahydrofuran (THF), CHCl₃, CH₂Cl₂, and toluene, and exhibited intense photoluminescence in THF (the emission maxima were located from 478 to 535 nm) and in film (from 478 to 578 nm). The low onsets of the oxidation potential (0.6–0.75 V) suggested that the alternating copolymers possessed a good hole‐transporting property due to the incorporation of triphenylamine moieties. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3278–3286, 2001     

Mechanisms of reduction in hole concentration in Al-doped 4H-SiC by electron irradiation

From the temperature dependence of the hole concentration in unirradiated lightly Al-doped 4H-SiC epilayers, an Al acceptor with E_V + 0.2 eV, which is an Al atom (Al_Si) at a Si sublattice site, and an unknown deep acceptor with E_V + 0.35 eV are found, where E_V is the top of the valence band. Both the densities are similar. With irradiation of 0.2 MeV electrons the Al acceptor density is reduced, while the unknown deep acceptor density is increased. Judging from the minimum electron energy required to displace a substitutional C atom (C_s) or the Al_Si, the bond between the Al_Si and its nearest neighbor C_s is broken due to the displacement of the C_s by this irradiation. Moreover, the displacement of the C_s results in the creation of a complex (Al_Si-V_C) of Al_Si and a carbon vacancy (V_C), indicating that the possible origin of the deep acceptor with E_V + 0.35 eV is Al_Si-V_C.     

Designing Hole Transport Materials with High Hole Mobility and Outstanding Interface Properties for Perovskite Solar Cells

Organic–inorganic halide perovskite solar cells (PSCs) have attracted much attention due to their rapid increase in power conversion efficiencies (PCEs), and many efforts are devoted to further improving the PCEs. Designing highly efficient hole transport materials (HTMs) for PSCs may be one of the effective ways. Herein we theoretically designed three new HTMs (FDT−N, FDT−O, and FDT−S) by introducing a nitrogen-phenyl group, an oxygen atom, and a sulfur atom into the spiro core of an experimentally synthesized HTM (FDT), respectively. And then we performed quantum chemical calculation to study their application potential. The results show that the devices with FDT−O and FDT−S instead of FDT may have higher open circuit voltages owing to their lower highest occupied molecular orbital (HOMO) energy levels. Moreover, FDT−S exhibits the best hole transport performance among the studied HTMs, which may be due to the significant HOMO-HOMO overlap in the hole hopping path with the largest transfer integral. Furthermore, the results on interface properties indicate that introducing oxygen and sulfur atoms can enhance the MAPbI₃/HTM interface interaction. The present work not only offers two promising HTMs (FDT−O and FDT−S) for PSCs but also provides theoretical help for subsequent research on HTMs.     

激光破岩特性研究

本文对强激光应用于油气井下进行激光射孔作业进行了研究,对比了光纤激光器与二氧化碳激光器在破岩效率上的区别,并从数值模拟和实验两方面研究了岩石受激光照射后的温度场分布以及岩石内部孔洞形状的成因。     

Dilaton Black Hole Tunneling Radiation in de Sitter Universe

The Hawking radiation via tunneling from the dilaton black hole in de Sitter universe is investigated using Parikh Wilczek＇s method. We show that if the self-gravitational interaction and energy conservation are taken into account, the modified radiation spectrum deviates from exact thermal spectrum and satisfies the unitary theory.