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Ekaterina Radeva, Krum Kolentsov, Lyliana Yourukova “Georgi Nadjakov” Institute of Solid State Physics - BAS Plasma polymerization is a modern and prospective method for obtaining thin dielectric films, which possess mechanical, chemical, thermal, radiation stability and good adhesion to any substrate. That is way they could be very attractive as protective and capsulating layer in electroluminescent display structures. The paper refers to synthesis of plasma polymers from hexamethyldisiloxane on the heterogeneous matrix of the emitting layer. The polymer layer of high cross-linking and branched structure and thickness below 1 micron protects the structure against electrical breakdown. More over the deposition of the same polymer as upper layer on the whole structure protects it from environmental conditions. The optical and photoluminescent properties of plasma polymer layers synthesized from hexamethyldisiloxane are examined. The value of the polymer layer transparence is in the limits from 55% at 400 nm to 88% at 800 nm. The photoluminescence is stimulated by using the spectral line 365 nm emitted by a Hg spectral lamp. As a result of the study the new electroluminescent display structure, in which the protective and capsulating layer is organosilicon plasma polymer, is prepared by perfect technology. The structure obtained is characterized by à significant increase of the emission brightness, compared to inorganic protective layers. For electroluminescent structures with a chalcogenide protective layer the increase is more than 6 times and for structures with heterogeneous matrix on the base of TiO2 – more than 20 times. Às à stable coating the organosilicon plasma polymer increases the lifetime of the electroluminescent structures over 15 000 working hours and radiation stability (Gama-radiaotion) up to 0,5 Mrad. The electroluminescent display structure with presented advantages is ready for economic realization in various fields of the modern society – light information in the metropolitan, airports, auto and railway stations, dispatch points, commodity and currency exchange, banks, hospitals, hotels, technological & production lines etc.
Keywords: plasma polymerization, organosilicon polymers, thin films, electroluminescent display structure
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Created: 30 August 2011 |