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XPS Studies of PtCl 4 and H 2 PtCl 6 ·6H 2 0 doped polyacetylene
Author(s) -
Yong Cao,
KeZhen Guo,
RenYuan Qian
Publication year - 1985
Publication title -
acta chimica sinica english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 0256-7660
DOI - 10.1002/cjoc.19850030106
Subject(s) - polyacetylene , chemistry , dopant , platinum , x ray photoelectron spectroscopy , crystallography , doping , binding energy , atom (system on chip) , analytical chemistry (journal) , atomic physics , nuclear magnetic resonance , organic chemistry , materials science , catalysis , physics , optoelectronics , computer science , embedded system , polymer
The PtCl 4 and H 2 PtCl 6 ‐6H 2 O doped polyacetylene were studied by X‐ray photoelection spectroscopy and transmission electron microscopy. We found that both Pt 4f and Cl 2p peaks could be resolved into two components both with a splitting of ca. 1.5 eV. The higher binding energy components of Pt 4 f peak is attributed to Pt 4+ and the lower binding energy one to Pt 2+ species. From quantitative analysis of the results of decomposition of both Pt 4 f and Cl 2p peaks it was found that an atomic ratio of chlorine to platinum for Pt 2+ species is (Cl) / (Pt) = 2 and that for Pt 4+ species is (Cl) / (Pt) = 6 for both PtCl 4 and H 2 PtCl 6 ·6H 2 O doped polyacetylene. The C 1s peaks could be decomposed into two components separated by ca. 1 eV. The intensity of the higher binding energy component increased with increasing dopant concentration. These indicate that the platinum salt doping proceeds through charge transfer from polyacetylene chain to platinum atom resulting in a partial reduction from Pt 4+ to Pt 2+ state. The existence of PtCl 2 cluster on the surface of the doped polyacetylene film was supported by transmission electron microscopy and electron diffraction observations. These results indicate that a random distribution of the dopant along the macromolecular chain, and the charge per carbon atom in the metallic region of doped polyacetylene has been estimated to be 0.2 |e|. From these results the mechanism of the PtCl 3 and H 2 PtCl 6 ·6H 2 O doping process in polyacetylene is clarified as follows:\documentclass{article}\pagestyle{empty}\begin{document}$$ \begin{array}{ll} {2{{\rm PtCl}}_4 + 2{{\rm e}}-{{\rm PtCl}}_6^{2 - } + {{\rm PtCl}}_2 } & {{{\rm for}}\;{{\rm PtCl}}_4 \;{{\rm doping}};}\\{2{{\rm H}}_2 {{\rm PtCl}}_5 + 2{{\rm e}} - {{\rm PtCl}}_6^{2 - } + {{\rm PtCl}}_2 + 4{{\rm HCl}}} & {{{\rm for}}\;{{\rm H}}_2 {{\rm PtCl}}_6 \cdot 6{{\rm H}}_2 {{\rm O}}\;{{\rm doping}}{{\rm .}}}\\ \end{array} $$\end{document}Thus the dopant anion in polyacetylene is PtCl, 2− for both PtCl 4 and H 2 PtCl 6 ·6H 2 O doping.