Evolution of the unoccupied states in alkali metal-doped organic semiconductor

The evolution of the electronic structure, especially the unoccupied states, induced by alkali metal doping has been investigated with photoemission and inverse photoemission spectroscopy for organic semiconductors, such as copper-phthalocyanine (CuPc) and tris(8-hydroxyquinoline) aluminum (Alq). The n-type doping leads to a downward shift for the lowest unoccupied molecular orbital (LUMO) of the organic semiconductors, until the edge of the LUMO reaches the Fermi level. After that, the LUMO intensity decreases monotonically, while a gap state grows in the valence spectra, which gives direct evidence for the origin of the doping-induced gap state in organic molecules. The modification of the LUMO intensity, as well as that of the gap state, suggests the formation of multiply charged anions in heavily doped film.     

High-precision sample stage for photoemission microscopy of organic films

A high-precision sample stage for photoemission microscopy has been constructed to translate the sample by ±3 mm with accuracy better than 100 nm. The stage is actuated by step motors settled outside the vacuum. The accuracies of the translations were measured by observing a standard patterned sample with a photoemission electron microscope (PEEM) of 50 nm resolution. The accuracy was nearly independent of the distance of each translation step and the error was not accumulated by repeated steps. After round-trip translations up to 0.2 mm, the sample came back to the original position with accuracy of ±50 nm. The performance of the stage was demonstrated by observing growth processes of lead phthalocyanine (PbPc) films formed on graphite.     

Spin-peierls transition in dimerized stacks of anion-radical salt (N-Me-2,5-di-Me-Pz)(TCNQ)2, (Pz is pyrazine)

An anion-radical salt (ARS) (N-Me-2,5-di-Me-Pz)(TCNQ)₂, where Pz is pyrazine, was synthesized and its crystal structure was resolved. X-ray diffraction experiments on single crystals were performed. Heat capacity was measured in the temperature range from 2 to 300 K. Magnetisation and magnetic susceptibility were measured in the temperature range from 2 to 300 K and the low-temperature part was measured in magnetic fields from 5 mT to 5 T. The experimental results were explained in terms of dimerized Heisenberg spin chain model. Numerical calculations were performed and compared with experimental data.     

Adsorption energy and geometry of physisorbed organic molecules on Au(1 1 1) probed by surface-state photoemission

The modification of the Au(1 1 1) Shockley-type surface state by an adsorbed monolayer of large π-conjugated molecules was investigated by high-resolution angle-resolved photoelectron spectroscopy (ARPES). We determined binding energy, band mass, and Rashba-splitting and discuss the results in the context of rare-gas adsorption on noble metals. This comparison allows the determination of the bonding strength of the adsorbates, found to be physisorptive with derived binding energies per molecule of 2.0 eV for perylene-tetracarboxylic-dianhydride (PTCDA) and 1.5 eV for naphtalene-tetracarboxylic-dianhydride (NTCDA). We will also present a superstructure model for the NTCDA/Au(1 1 1) system, deduced from low energy electron diffraction images (LEED) in combination with substrate band-backfolding.     

有机盐类化合物醋酸钠的电喷雾质谱研究

利用电喷雾质谱技术研究了有机盐类化合物醋酸钠(NaAc)的特征质谱行为,实验结果表明,在全扫描电喷雾正负离子谱中都出现了质量数相差82的质谱峰簇．这与醋酸钠的相对分子质量相一致,正负质谱峰簇分别对应于簇合物离子Na^ (NaAc)n和Ac^-(NaAc)m:簇合物离子的多级串联质谱进一步证明了簇合物离子的存在。该结果为类似结构的盐类化合物的表征提供了一种新的质谱证据。     

聚合物支载的有机催化剂Ⅰ.非手性有机催化剂

对二十余年来聚合物支载的有机催化剂的合成、性能及其在催化反应中的应用,包括负载催化剂的回收和重复使用等进行了综述.用于支载体的聚合物包括交联聚合物、线型聚合物及树形聚合物;支载的有机催化剂包括手性及非手性催化剂两类.本文作为第一部分将介绍聚合物支载的非手性有机催化剂,包括相转移催化剂、氧化催化剂、酸以及碱催化剂.     

有机硅、氟高分子表面活性剂在建材中的应用发展

综述了有机硅、含氟高分子表面活性剂及含有机硅氟的高分子表面活性剂的种类和研究进展,介绍了它们在涂料工业、塑料工业等建材领域中的应用。     

水中有机污染物的近红外光谱快速鉴别

讨论了水中有机污染物的近红外光谱,指出不同的有机污染物在近红外光谱区表现出不同的特征,用该特征结合化学计量学技术可快速对有机污染物做出鉴别。     

一种新型共掺杂稀土配合物的发光特性

制备了一类以苯甲酰水杨酸 (BenzoylSalicylicAcid ,BSA)为第一配体 ,邻菲罗啉 (phenanthroline ,phen)为第二配体的共掺杂稀土铕镧配合物La0 6Eu0 4(BSA) 3 phen。用其作为发光层材料制作了电致发光器件 :ITO/PVK :La0 6Eu0 4(BSA) 3 phen/Alq/Al。讨论并证明了稀土La3 与Eu3 之间存在F rster能量传递。同时将该器件与器件ITO/PVK :Eu(BSA) 3 phen/Alq/Al和ITO/PVK :Tb0 6Eu0 4(BSA) 3 phen/Alq/Al的发光进行了比较。表明该器件具有单色性好 ,整流性好的特性 ,同时得到了最大亮度为 10 2尼特的红光