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Ultramicroanalysis of Conducting Polymers with Atom-Probe

用原子探针对导电聚合物进行超微量分析

基本信息

批准号：
61460062
负责人：
NISHIKAWA Osamu
金额：
$ 4.54万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

项目摘要

The purpose of this study is to clarify the structures and binding states and the distrubution of dopants of the conducting polymer, polypyrrole(PP), and the effect of oxidation fully utilizing the unique capability of the atom-probe(A-P). Usefulness of the ultramicroanalysis of high temperature superconducting ceramics with A-P was examined.A-P specimens are fine needles with a tip radius of less than 1000<ang>. Since it is not easy to make a sharp polymer tip, a thin PP film was fablicated on a Pt tip by electrochemically polymerizing pyrrole. The dopants to make PP conductive are ClO_4^- and BF_4^-. PP-metal interfaces were formed by depositing a metal film in the UHV A-P.The distribution of cluster ions detected by the A-P mass analysis indicates that an oxgen atom breaks in a C-H bond of PP and then release H forming a stable C=O double bond. The thickness of the fully oxidized PP film is approximately 500<ang> after 3 month exposure to air. The Cl atoms dpoed in PP were not detected possibly due to its high vapor pressure. On the contrary, boron with the high melting temperature migrates away from the oxidezed regions of PP by the repulsive B-O interaction and is detected from the non-oxidized PP.Al^+, Ag^+, AlO^+ and AgO^+ were detected from the Al, Ag or In films deposited on PP but In was detected with various oxidized PP fragments, such as In-Co^+, In-C _2O_2^+ and In-C_2 NO^+.In order to explain the superconduction mechanism of high Tc ceramics, a new model has been proposed. In this model, extra oxygen atoms absorbed on the ceramic surface draw electronic charge from the oxygen atoms of the Cu-O network of the ceramics. Then, the induced lone pair orbitals of the network oxygen are electronically polarized and interactwith the conduction electrons and generate the inter-electron attractive force and the Cooper pairs which make the ceramics superconductive.

本研究的目的是充分利用原子探针（A-P）的独特能力，阐明导电聚合物聚吡咯（PP）的结构、结合状态、掺杂物分布以及氧化效应。探讨了用A-P对高温超导陶瓷进行超微分析的可行性。a - p试样为细针，针尖半径小于1000< 10>。由于不易制作尖锐的聚合物尖端，采用电化学聚合吡咯的方法在Pt尖端上制备了一层薄薄的PP薄膜。使PP导电的掺杂剂是ClO_4^-和BF_4^-。通过在特高压a - p中沉积金属膜形成pp -金属界面。a - p质量分析检测到的簇离子分布表明，氧原子在PP的C-H键断裂后释放H，形成稳定的C=O双键。在空气中暴露3个月后，完全氧化的PP膜的厚度约为500< 1>。未检测到掺杂在PP中的Cl原子，可能是由于PP的蒸气压较高。在PP表面沉积的Al、Ag或In薄膜中检测到Al^+、Ag^+、AlO^+和AgO^+，而在各种氧化的PP碎片中检测到In，如In- co ^+、In- c _2O_2^+和In- c_2 NO^+。为了解释高温陶瓷的超导机理，提出了一种新的模型。在该模型中，陶瓷表面吸收的额外氧原子从陶瓷的Cu-O网络的氧原子中吸取电子电荷。然后，网络氧的诱导孤对轨道被电子极化，并与传导电子相互作用，产生电子间的吸引力和库珀对，使陶瓷具有超导性。