Title of Invention

"A PROCESS FOR THE PREPARATION OF CONDUCTING POLYMER BASED DIODES".

Abstract

This invention relates to a process for the preparation of conducting polymer based diode which comprises in subjecting a monomer to the step of polymerization by using oxidizing agents like per-sulphate, ferric chloride in the presence of 10-90 weight percent of a semiconducting oxides as herein described, the polymerizing solution is filtered, the composite powder herein described obtained is subjected to the step of washing and drying and then the said dry powder is pressed to form pellets or any other shape as desired. .

Full Text

FIELD OF INVENTION This invention relates to a process for the preparation of conducting polymer based diodes, OBJECTS OF THE INVENTION A primary object of this invention is to propose a process for the preparation of conducting polymer based diode which is simple and inexpensive. Another object of this invention is to propose a process for the preparation of conducting polymer based diode in various dimensions and forms. Still another object of this invention is to propose a process for the preparation . of conducting polymer based diode and wherein the onset or knee voltage can be varied easily. Yet another object of this invention is to propose a process for the preparation of conducting polymer based diode having very high reverse breakdown voltage. Further objects and advantages of this invention will be more apparent from the ensuing description. BRIEF DESCRIPTION OF THE INVENTION According to this invention there is provided a process for the preparation of conducting polymer based diode which comprises in subjecting a monomer to the step of polymerization by using oxidizing agents like per-sulphate, ferric chloride in the presence of 10-90 weight percent of a semiconducting oxides as herein described, the polymerizing solution is filtered, the composite powder herein described obtained is subjected to the step of washing and drying and then the said dry powder is pressed to form pellets or any other shape as desired. In accordance with this invention the process comprises in preparing a conducting polymer semiconductors oxide composite by chemical polymerization of the monomers like aniline, pyrrole thiophene etc. in the presence of 10-90 weight percentage of N-type semi conducting oxides material such as Titanium dioxide (TiO2), zinc oxide (ZnO), cadmium (CdO), lead oxide (PdO) etc. while the polymerization of the conducting polymer is going on [which acts like a P-type material], forms a composite. The oxidizing agent used during polymerization are ammonium persulphate (MM4)2S2O8, ferric chloride (FeCl3) etc, The composite powder is filtered using filter paper. After washing the? composite powder by water, acetone,, methanol etc., dried (either vacuum dried by a rotary pump or kept in the dessicator for a long time i,e. for one week } . The dry composite powder is pressed to prepare the small pellets (by taking 0.35 qm of the powder) and applying a pressure of 3 tones. The current voltage characteristics of these pellets were measured by using silver and aluminum electrodes, which shows typical shortkey diode characteristics. Reference is hereinafter made to working examples, but which are not to be construed in a limited manner. Thus, the reference to numerals in the following examples are only exemplary in nature. Further, reference in the working example is made to polyaniline as the polymer. However, the present process is applicable to all other conducting polymers such as Polypyrrole (PPy), Polyacetylene, Polythiophene etc. which can be chemically polymerized and doped while polymerization is q o going on. 5.3 qm of (NH4)2S2O8,is dissolved IN 50 nil double distilled water,, and added to a suspension of 10 ml aniline monomer (with 1.1 ml 0,1 M HC1) in a 100 ml double distilled water, containing 5 weight percentaqe of TiO2, The polymerizing solution is kept at O°C for 30 hourS, The polyaniline TiO2, composite powder is filtered using filter paper, washing by water, acetone and methanol and vacuum dried for about 30 mins by a rotary pump. The dry composite powder obtained is pressed in the form of thin discs of diameter" 1.1 cm and 0,3 cm thickness, by applying a pressure of 3 tons for 2 mins. The current—voltage characteristics were traced by sandwiching the pellet between silver and aluminium electrodes,, The readings were taken continuously and with in creasing the voltage,, The typical Schottky Diode characteristics were obtained as shown in figure (l.A and 2A) , EXAMPLE. 2 5.3 gin of (NH4)2S2O8, is dissolved in 50 ml double distilled water, which is. added to a suspension of 10 rid aniline monomer (with .1.1 ml 0.1 M HC1 } in a 100 ml double distilled water, cont.ain.inc) 70 weiqht percentage of TiO2, The polymerizing solution is kept at, Ooc for 30 hours. The polyani1ine TiO2, composite powder is filtered using filter paper, washing by water, acetone and inethanol and vacuum dried for about 30 mins by a rotary pump,, The dry composite powder obtained is pressed in the form of thin discs of diameter 1.1 cm and 0.3 cm thickness, by applying a pressure of 3 tons for 2 mins. The current voltage characteristics were traced by sandwiching the pellet between silver and aluminium electrodes. The readings were taken continuously and with increasing the voltage?. The typical Schottky Diode characteristics were obtained as shown in figure (IB and 2B) . FABRICATION OF THE DEVICE Figures ( 1A and IB and 2A and 2.8) shows the I-V characteristics of the PAN I Ti02 composites with Ti.02 addition (i)0.5525 qm and (ii) 8.135 qm, while the Polyaniline polymerisation is going on. It shows the rectifying behaviour of the composites. In this figure, positive (1st) quadrent corresponds to silver electrode positive while in the negative (3rd) quadrent, aluminium electrode is positive, The readings were taken installtenoustenously at room temperature The typical diode characteristics of the resulting conducting polymer has eel device can be attributed to either (1) formation of the schottky barrier at the silver/ (PANI+ TiO2, ) composite or" (2) •formation of the "micro" P—N junctions at the P PANI/ TiO2, composite at their microinterfaces, CLAIM: 1. A process for the preparation of conducting polymer based diode which comprises in subjecting a monomer as herein described to the step of polymerization by using oxidizing agents like per- sulphate, ferric chloride in the presence of 10-90 weight percent of a semiconducting oxides as herein described, the polymerizing solution is filtered, the composite powder herein described obtained is subjected to the step of washing and drying and then the said dry powder is pressed to form pellets or any other shape as desired. 2. A process as claimed in claim 1 wherein said semi conducting oxides used are for example Titanium Dioxide, zinc oxide, cadmium oxide, lead oxide etc. 3. A process as claimed in claim 1 wherein said the polymerizing solution is filtered by using a filter paper. 4. A process as claimed in claim 1 wherein said powder is washed by using water, acetone, and/or methanol. 5. A process for the preparation of conducting polymer based diodes substantially as herein described and illustrated.

Documents:

859-del-1999-abstract.pdf

859-del-1999-claims.pdf

859-del-1999-correspondence-others.pdf

859-del-1999-correspondence-po.pdf

859-del-1999-description (complete).pdf

859-del-1999-drawings.pdf

859-del-1999-form-1.pdf

859-del-1999-form-19.pdf

859-del-1999-form-2.pdf

859-del-1999-form-4.pdf

859-del-1999-form-5.pdf

859-del-1999-gpa.pdf

859-del-1999-petition-138.pdf