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Luminescence of heat-treated silicon-based polymers: promising materials for LED applications

Menapace, Ilaria and Mera, Gabriela and Riedel, Ralf and Erdem, Emre and Eichel, Rüdiger-A. and Pauletti, Alberto and Appleby, Graham A. (2008):
Luminescence of heat-treated silicon-based polymers: promising materials for LED applications.
In: Journal of Materials Science, Springer, pp. 5790-5796, 43, (17), ISSN 0022-2461,
[Online-Edition: http://dx.doi.org/10.1007/s10853-008-2882-9],
[Article]

Abstract

A new strategy to obtain transparent, thermally stable, and formable photoluminescent materials for LED applications is presented. Starting from commercially available silicon-based polymers, luminescence properties are developed by means of simple heat treatment. Solid polymethylsilsesquioxane MK (Wacker-Besil�PMS MK) and liquid poly(ureamethylvinyl)silazane Ceraset (Kion Ceraset� PUVMS) were thermally treated between 200 and 700 °C for 2 h under Ar atmosphere. Photoluminescence properties were observed in all the samples. The structural rearrangements during thermal annealing were effective in order to red-shift the emission spectra of the untreated polymers to the visible range. The formation of dangling bonds and carbon sp2, associated with the annealing procedure and confirmed by means of Electron Paramagnetic Resonance (EPR) spectroscopy and solid state Magic Angle Spinning NMR (MAS-NMR) contribute to the redshift of the photoluminescence emissions of the polymers. After heat treatment at low temperatures (200, 300, and 400 °C), both the polymers show fluorescence in the UV range. While the polysiloxane reveals white luminescence after annealing at 500 and 600 °C, the polysilazane heattreated at 500 °C exhibits emission in the blue-green range and is transparent. At higher temperatures the presence of free carbon counteracts the luminescence properties.

Item Type: Article
Erschienen: 2008
Creators: Menapace, Ilaria and Mera, Gabriela and Riedel, Ralf and Erdem, Emre and Eichel, Rüdiger-A. and Pauletti, Alberto and Appleby, Graham A.
Title: Luminescence of heat-treated silicon-based polymers: promising materials for LED applications
Language: English
Abstract:

A new strategy to obtain transparent, thermally stable, and formable photoluminescent materials for LED applications is presented. Starting from commercially available silicon-based polymers, luminescence properties are developed by means of simple heat treatment. Solid polymethylsilsesquioxane MK (Wacker-Besil�PMS MK) and liquid poly(ureamethylvinyl)silazane Ceraset (Kion Ceraset� PUVMS) were thermally treated between 200 and 700 °C for 2 h under Ar atmosphere. Photoluminescence properties were observed in all the samples. The structural rearrangements during thermal annealing were effective in order to red-shift the emission spectra of the untreated polymers to the visible range. The formation of dangling bonds and carbon sp2, associated with the annealing procedure and confirmed by means of Electron Paramagnetic Resonance (EPR) spectroscopy and solid state Magic Angle Spinning NMR (MAS-NMR) contribute to the redshift of the photoluminescence emissions of the polymers. After heat treatment at low temperatures (200, 300, and 400 °C), both the polymers show fluorescence in the UV range. While the polysiloxane reveals white luminescence after annealing at 500 and 600 °C, the polysilazane heattreated at 500 °C exhibits emission in the blue-green range and is transparent. At higher temperatures the presence of free carbon counteracts the luminescence properties.

Journal or Publication Title: Journal of Materials Science
Volume: 43
Number: 17
Publisher: Springer
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Dispersive Solids
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 16 Apr 2012 09:01
Official URL: http://dx.doi.org/10.1007/s10853-008-2882-9
Identification Number: doi:10.1007/s10853-008-2882-9
Funders: The authors thank the European Community FP6 (MCRTN-019601, PolyCerNet), the Deutsche Forschungsgemeinschaft, Bonn, Germany (DFG-NSF research initiative), and the Fonds der Chemischen Industrie, Frankfurt, Germany for financial support.
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