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Highly Stable Red‐Emitting Sr2Si5N8:Eu2+ Phosphor with a Hydrophobic Surface |
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| Authors: | Bi Zhang Jun‐Wei Wang Lu‐Yuan Hao Xin Xu Simeon Agathopoulos Liang‐Jun Yin Cheng‐Ming Wang Hubertus T. Hintzen |
| Affiliation: | 1. Chinese Academy of Science Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, Anhui, China;2. Materials Science and Engineering Department, University of Ioannina, Ioannina, Greece;3. School of Energy Science and Engineering, University of Electronic Science and Technology of China, Chengdu, China;4. Luminescent Materials Research Group, Faculty of Applied Sciences, Delft University of Technology, Delft 2629, Netherlands |
| Abstract: | One of the biggest problems in white light‐emitting diodes (WLEDs) is the moisture‐induced degradation of phosphors. This paper proposes a simple and feasible surface modification method to solve it, whereby a hydrophobic surface layer is developed on the surface of the phosphors. The particular case of orange‐red‐emitting Sr2Si5N8:Eu2+ (SSN) phosphor was investigated. The mechanism to develop the hydrophobic layer involves hydrolysis and polymerization of tetraethylorthosilicate (TEOS) and polydimethylsiloxane (PDMS). The experimental results showed that the surface layer of SSN phosphor was successfully modified to a hydrophobic nanolayer (8 nm) of amorphous silicon dioxide that contains CH3 groups in the surface. This hydrophobic surface layer gives the modified phosphor superior stability in high‐pressure water steam conditions at 150°C. |
| Keywords: | coatings heat treatment hydrolysis nitrides optical materials/properties |