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Hole injection initiated by ionic conduction in electrically stressed insulating polymers
Author(s) -
Kao Kwan C.,
Tu Demin
Publication year - 2003
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.12849
Subject(s) - anode , materials science , ionic bonding , polymer , space charge , thermal conduction , quantum tunnelling , ion , ionic conductivity , impurity , electric field , cathode , chemical physics , composite material , condensed matter physics , optoelectronics , chemistry , electrode , electron , electrolyte , physics , organic chemistry , quantum mechanics
A new mechanism leading to hole injection into insulating polymers under normal operating fields is presented. In general, it is unlikely that holes can be injected into large band‐gap insulating materials under normal operating fields less than 1 MV cm −1 , particularly for materials that are not in the form of thin films. However, insulating polymers consist of a large amount of various unavoidable ionic impurities, so ionic conduction plays an important role in their electrical properties. The presence of such ions modifies the field distribution in the material with the tendency of enhancing the field toward the anode, thus increasing the probability for hole tunneling from the anode to the material. The appearance of positive space charge near the anode after a prolonged period of electrical stressing, as observed by many investigators, may be considered as the experimental evidence of the mechanism. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1864–1867, 2003