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Luminescent materials through the re...

Green, William Harry.

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Luminescent materials through the reaction of silicon and silicon dioxide with carboxylic acids.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Luminescent materials through the reaction of silicon and silicon dioxide with carboxylic acids./
Author:	Green, William Harry.
Description:	242 p.
Notes:	Source: Dissertation Abstracts International, Volume: 60-05, Section: B, page: 2123.
Contained By:	Dissertation Abstracts International60-05B.
Subject:	Chemistry, Inorganic. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9930895
ISBN:	0599309784

Luminescent materials through the reaction of silicon and silicon dioxide with carboxylic acids.
Green, William Harry.

Luminescent materials through the reaction of silicon and silicon dioxide with carboxylic acids. - 242 p.

Source: Dissertation Abstracts International, Volume: 60-05, Section: B, page: 2123.

Thesis (Ph.D.)--University of California, San Diego, 1999.

This work concerns the luminescence of materials made via the electrochemical and chemical reaction of silicates with carboxylic acids. The current effort in this area began with electroluminescence (EL) studies of porous silicon electrodes immersed in carboxylic acid electrolytes. We found that bright red EL could be generated by applying a positive bias to n- or p-type porous silicon electrodes in carboxylic acid electrolyte. The formation of an oxide layer during the experiment, however, prevents efficient charge transfer with the porous layer and shuts down the electrolurninescence after a short time. Despite the loss of electroluminescent activity, oxidized porous silicon electrodes typically retain strong visible photoluminescence, suggesting that oxidation does not destroy the chromophore. We speculated that charge transfer with the silicon nanocrystallites may still be possible if charge carriers could be injected through the oxide layer. Although it was found that visible EL could be observed from oxidized porous silicon electrodes, the source of the emission was found to originate from the oxide layer. The electroluminescence appeared to be related to radiative trapping and detrapping of electrons at defect sites in the bulk oxide, while the photoluminescence was due to the incorporation of organic material into the oxide.

ISBN: 0599309784Subjects--Topical Terms:

517253
Chemistry, Inorganic.

Luminescent materials through the reaction of silicon and silicon dioxide with carboxylic acids.
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020 $a 0599309784
035 $a (UnM)AAI9930895
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040 $a UnM $c UnM
100 1 $a Green, William Harry. $3 1928034
245 1 0 $a Luminescent materials through the reaction of silicon and silicon dioxide with carboxylic acids.
300 $a 242 p.
500 $a Source: Dissertation Abstracts International, Volume: 60-05, Section: B, page: 2123.
500 $a Chair: Michael J. Sailor.
502 $a Thesis (Ph.D.)--University of California, San Diego, 1999.
520 $a This work concerns the luminescence of materials made via the electrochemical and chemical reaction of silicates with carboxylic acids. The current effort in this area began with electroluminescence (EL) studies of porous silicon electrodes immersed in carboxylic acid electrolytes. We found that bright red EL could be generated by applying a positive bias to n- or p-type porous silicon electrodes in carboxylic acid electrolyte. The formation of an oxide layer during the experiment, however, prevents efficient charge transfer with the porous layer and shuts down the electrolurninescence after a short time. Despite the loss of electroluminescent activity, oxidized porous silicon electrodes typically retain strong visible photoluminescence, suggesting that oxidation does not destroy the chromophore. We speculated that charge transfer with the silicon nanocrystallites may still be possible if charge carriers could be injected through the oxide layer. Although it was found that visible EL could be observed from oxidized porous silicon electrodes, the source of the emission was found to originate from the oxide layer. The electroluminescence appeared to be related to radiative trapping and detrapping of electrons at defect sites in the bulk oxide, while the photoluminescence was due to the incorporation of organic material into the oxide.
520 $a To test the idea that the photoluminescence of the electrochemical oxide was of a molecular origin, we attempted to synthesize a similar material through a sol-gel route. Reaction of tetraalkoxysilanes with a variety of organic acids leads to a solid glass that displays little photoluminescence when first prepared. After a simple heat treatment in air between 200--500°C, however, the silicates display intense white photoluminescence between 450--600 min. The external quantum yield ranges from 0.20--0.45 and the lifetimes are <10 ns. Spectroscopic results indicate the chromophore in these materials is associated with molecules trapped in the lattice during the heat treatment. By substituting amino- functional alkoxysilanes for the tetraalkoxysilanes in the synthesis, another class of highly luminescent (phi = 0.3--0.4) materials results. The transparent yellow-orange polymers are easily processed in to a variety of forms and display complex photophysical behavior.
590 $a School code: 0033.
650 4 $a Chemistry, Inorganic. $3 517253
650 4 $a Chemistry, Polymer. $3 1018428
690 $a 0488
690 $a 0495
710 2 0 $a University of California, San Diego. $3 1018093
773 0 $t Dissertation Abstracts International $g 60-05B.
790 1 0 $a Sailor, Michael J., $e advisor
790 $a 0033
791 $a Ph.D.
792 $a 1999
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=9930895