Site: Elorma Scientific Industrial Corporation
(Renamed Elorma Joint Stock Corporation as of 11/94)
4 Kosygin Str., 11-420
Date Visited: October 29, 1993
Report Author: J. Talbot
Prof. Alexander A. Ovchinnikov
Prof. Val N. Spector
The Elorma enterprise was formed by members of the Institute of Chemical Physics of the Academy of Sciences who study solid-state organic materials such as dielectrics, semiconductors, and ferromagnetics. Professor Alexander Ovchinnikov first formulated the theory of ferromagnetic organic materials starting in about 1977; he reported the fabrication of the first organic ferromagnet in 1986. There are now 37 researchers in the department, since many have left the institute due to financial problems; 25% have left the country and 25% are working outside of the institute. A tour of the institute's facilities showed exceptionally well-equipped laboratories that contain FTIR, DSC, Raman spectroscopy, nano- and picosecond laser spectrometers, and a dedicated Convex computer.
In display technology, the institute's scientists have investigated a DC and AC EL display. This display consisted of ZnO-ZnS p-n junction with an organic polymer dielectric. The display was a 4" x 5" matrix display, sealed with silicone rubber. The color was yellow-green with an integral brightness of 180-250 cd/m2, which was visible in sunlight. The luminescent material was a modification of existing phosphor in which ZnS particles were oxidized, covered with patches of Cu islands, and coated with a siloxane film.
The role of Elorma in making the display was to modify the interface to enhance the electron mobility of the phosphors. Other phosphors were also used, such as rare earth oxides for blue. The siloxane used in the display was patented; the patent is to be released in February 1994. Elorma's scientists are interested in using the siloxane material developed at Elorma as a sublayer for photodiodes and possibly as a substrate coating for displays. The proposed advantage of this organic is that it can protect the phosphors from alkalis from soda-lime glass substrates and thus enhance reliability and stability. The siloxane polymer [RSi(Me)O1.5n (where Me can be Al) can be a trap for the ions of alkali metals, thereby diminishing diffusion of alkalis by several orders of magnitude, and thereby stop diffusion of alkalis. The ligamer is of the form [R SiO(OH)]n [RSiO1.5])n). The siloxane changes state from 180-230 degrees centigrade; from 450-480 degrees centigrade, degradation begins to occur by loss of surface atoms, and at 700 degrees centigrade the bulk properties are damaged. However, thin films or composites of this material are not damaged. A sample of a composite of the siloxane and asbestos was shown. Possible future applications of these organic materials were proposed, such as a substrate in an LCD and a photodioxide screen in a LED with narrowband emission. Elorma's work was published in Russian Chemical Reviews. The Japanese reproduced Elorma's material after this initial publication, and now PULSAR (in Moscow) purchases the Japanese- made siloxane.
For displays, the reason for using siloxane as a dielectric is that a 3 mm thick film can be made with þ = 1.8, breakdown with a field of 5 x 106 V/cm. The material has good characteristics for vacuum use. The disadvantage in producing the oligomer is its high rate of monomer reaction, which makes processing difficult to control. A properties data sheet of the siloxane is available.
The organic semiconductors also can be used as gas sensors with a high selectivity; NO2 can be detected at 12-15 ppb levels. An NO2 sensor is being developed. However, the gas desorption in this type of sensor tends to be slow which limits its use. Another application is as a soft X-ray sensor (the X-ray absorbance of the material is similar to that of human tissue), which was published in 1975. Organic materials have been developed with antibacterial properties (Prof. V.M. Mysin) and for high precision temperature, flow, and level sensors (Dr. L.V. Belikov). The group has done work in carbon-carbon composite materials, in which a phenolic resin is treated with an organic additive (up to 10%) and heated to 600-1500 degrees centigrade to yield 50-60% carbon. If boron is also added, the yield increases to 80-85% in one step to replace the conventional multiple-step heating-material impregnation cycle needed to make a porous carbon material. Also, the scientists described a new method for making carbon fibers that increases their oxygen stability 70-100 times.
Dielectric Materials for Thin Films
Prof. L.V. Belikov
Prof. B.A. Kamaritskii
Professor V.M. Mysin
Ton'shin, A.M., B.A. Kamaritskii, A.M., and V.N. Spektor. 1983. "The Technology, Structure and Properties of Organosilicon Dielectrics - Polyorgano-silsesquioxcanes." Russian Chemical Reviews. 52(8):1365.