Low-Temperature Electron Spin Resonance in (TMTSF)2PF6 in the High Pressure Metallic Phase

Abstract

The electron spin resonance of (TMTSF)₂PF₆ has been observed at low fields (H_o < 110 Oe) in the high pressure, metallic phase (p > 6.5 kbar) in the temperature range 1-4^?K. The anisotropy in the g value is similar to that observed at ambient pressure above the metal-insulator transition. The linewidth is very narrow and the spin susceptibility strongly decreases as the superconducting transition is approached from above. We interpret this as evidence for singlet-paired superconductivity. Superconductivity is observed at 1.1 K and the critical field has angular dependence in the be plane. These observations lead us to conclude that (TMTSF)₂PF₆ is a singlet paired superconductor.     

铽配合物TbY(o-MBA)6(phen)2与PVK掺杂体系的发光性质研究

合成了一种新型的稀土铽配合物材料TbY(o-MBA)6(phen)2,把它作为发光材料应用于有机电致发光中.把铽配合物掺杂在导电聚合物PVK中采用旋涂法制得发光层,并利用AlQ作为电子传输层制作了多种结构的电致发光器件 器件A,ITO/PVK∶TbY (o-MBA)6(phen)2/LiF/Al;器件B,ITO/PVK∶TbY (o-MBA)6(phen)2/AlQ/LiF/Al;器件C,ITO/PVK∶TbY (o-MBA)6(phen)2/BCP/AlQ/LiF/Al.对器件A和B得到了纯正的、明亮的Tb3+离子的绿光发射,4个特征峰分别对应着能级5D4到7Fj(j=6,5,4,3)的跃迁,而PVK的发光完全被抑制.研究了掺杂体系的光致发光性能和电致发光性能,认为在光致发光中,铽的发光主要来源于PVK到稀土配合物的Frster能量传递.而在电致发光中,铽的发光主要来源于稀土配合物直接捕获载流子形成激子复合发光.并通过优化选择得到了发光性能较好的器件B,其最大亮度在14 V时达到213 cd·m-2.     

Polarized fluorescence and electroluminescence from rubbing-aligned conjugated polymers and their composites with fluorescent dyes

Polarized fluorescence and optical absorption studies of rubbing-treated poly(2,5-diheptyloxybenzene) and poly (3-alkylthiophene)s (PATs) were carried out with the aim of obtaining polarized electroluminescence (EL). It was revealed that there exists an optimum alkyl chain length in PATs for the effect of rubbing. Polarized EL with a dichroic ratio of 2.6 was observed from a rubbing-aligned PAT-12 film. It was also demonstrated that the rubbing treatment of composite films of PAT and several fluorescent dyes such as 1,4-bis (2-methylstyryl)benzene enabled us to obtain polarized emission from oriented dye molecules. © 1997 John Wiley & Sons, Ltd.     

Si (IV)-methoxyethylene-glycol-naphthalocyanine: synthesis and pharmacokinetic and photosensitizing properties in different tumour models

A Si(IV)-naphthalocyanine bearing two methoxyethylenglycol axial ligands to the centrally coordinated metal ion (SiNc) was prepared by chemical synthesis and assayed for the phototherapeutic activity after administration in a Cremophor formulation to C57BI/6 mice bearing a subcutaneously transplanted Lewis lung carcinoma or B16 pigmented melanoma. Pharmacokinetic studies indicate that the maximal accumulation in the tumour occurs at 24 h after intraperitoneal injection of 0.5 mg kg⁻¹ of SiNc, although the naphthalocyanine concentration in the Lewis lung carcinoma (0.70 μg g⁻¹) is significantly larger than that in the B16 pigmented melanoma (0.15 μg g⁻¹). This result in a higher selectivity of tumour targeting in the case of the lung carcinoma. Photodynamic therapy (782 nm, 370 mW cm⁻², 360 J cm⁻²) at 24 h after SiNc injection causes an efficient tumour response for Lewis lung carcinoma (50% lower tumour diameter on day 19 post-treatment as compared to untreated controls) while the pigmented melanoma shows only a minor response regarding the rate of tumour growth.     

柔性ACPEL显示器件的研究及应用

介绍了ＣＰＥＩ塑料基板为载体而制作的交流粉末电致发光显示器件（ＡＣＰＥＬ）。给出了亮度,效率,颜色与激发电压,频率之间的特性曲线,列出了器件的主要性能指标。     

First direct observation of EL2-like defect levels in annealed LT-GaAS

Nonstoichiometric arsenic-rich GaAs grown at low temperatures by molecular beam epitaxy (LT-GaAs) has been found to be semi-insulating after high-temperature annealing. The origin of this technologically important conversion is not yet fully understood. In order to study this effect, we performed photocurrent measurements on p-LT GaAs-n diodes in the spectral range between 0.75 and 1.5eV at 8K. The photocurrent spectra revealed the following features which are unique to the EL2 level: photoquenching, characteristic photoionization transitions to conduction band minima and a presence of a broad band due to the effect of auto-ionization from the excited state. Moreover, modeling of the optical excitation process using realistic band structure demonstrates that these features cannot be explained by “internal photoemission” originating from As precipitates, as the “buried Schottky barrier model” predicts. This is the first direct experimental evidence for the existence of EL2-like defect levels and their importance for understanding the optical and electronic properties of annealed LT-GaAs.     

Excitonic recombination processes in GaAs grown by close-space vapour transport

Epitaxial GaAs layers were grown using the close-space vapour transport. From deep level transient spectroscopy measurements, the native EL2 donor has been observed in all of the layers with deposition temperature-dependent concentration. On the GaAs samples, also performed are photoluminescence experiments in the temperature range 10-300 K. Two peculiar features were revealed: (i) the radiative recombination in GaAs layers is increasingly dominated by bound-exciton transitions, (ii) the excitonic luminescence is found to be very sensitive to the growth conditions. A study of the near-band-edge photoluminescence as a function of power excitation and temperature has been done in an attempt to elucidate the origin of the enhanced bound-exciton luminescence.     

一种微腔有机发光二极管的设计与性能研究

设计了PPV为发光层、Ag和DBR为上下反射镜、结构为Glass/DBR/ITO/PPV/Ag的微腔有机发光二极管。应用特征矩阵法,系统地研究了DBR和银镜的性质对器件性能的影响。结果表明:1)当金属厚度较小时,随着厚度的增加,器件的反射峰值不断增加并且蓝移,但是当厚度达到100 nm后,再增加厚度反射谱基本上没变化;2)随着DBR周期数的增加,器件的反射谱峰值不断增大,峰值半宽度不断变窄。3)器件的EL谱的峰值随着金属反射率的增加不断增大,而随着DBR反射率的增加是先增加后减小的。并给出了不同条件下DBR的最优化选择依据。     

掺杂型异质结有机电致发光二极管及其稳定性

研制了高效率、高稳定性的聚合物／有机物异质结掺杂型电致发光二极管（LED）,它以新型聚合物三苯基二胺衍生物（PTPD）为空穴传输材料,高效荧光材料红荧稀（Rubrene）为掺杂剂,异质结基本结构为PTPD／Alq3。双层掺杂时,器件电致发光（EL）的量子效率为1．47％,大约是未掺杂异质结器件0．74％的2倍;与未掺杂器件和常用的TPD／Alq3二极管相比,掺杂器件的稳定性有了显著的提高。讨论了异质结掺杂型LED稳定性改善机理。     

新型低压高效叠层有机白光器件

以Bphen:Li/WO3作为电荷产生层制备了低压、高效有机叠层白光器件.实验中,首先在器件中引入高导电性的载流子注入和传输层,有效降低了器件的驱动电压,然后通过电荷产生层垂直堆叠两个低压白光器件,获得了低压、高效有机叠层白光器件.叠层器件性能与单发光单元的器件相比较.其亮度及效率均有大幅提高,叠层器件的最大电流效率达到了17cd/A,在相同的电流密度下,叠层器件的效率约为传统器件的2.3倍.同时由于在叠层结构中引入了高导电性的载流子传输层,有效降低了器件的驱动电压,显著改善了白光器件的流明效率.叠层器件的流明效率相对于单发光单元器件提高了53%.