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Spectrally selective NbAlN/NbAlON/Si3N4 tandem absorber for high temperature solar applications

IR@NAL: CSIR-National Aerospace Laboratories, Bangalore

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Title Spectrally selective NbAlN/NbAlON/Si3N4 tandem absorber for high temperature solar applications
 
Creator Barshilia, Harish C
Selvakumar, N
Rajam, KS
Biswas, A
 
Subject Solar Energy
Optics
 
Description A new spectrally selective NbAlN/NbAlON/Si3N4 tandem absorber was deposited on copper substrates using a reactive direct current magnetron sputtering system. A high solar absorptance (0.956) and a low emittance (0.07) were achieved by gradually decreasing the refractive index from the substrate to the surface. The tandem absorber was characterized using solar spectrum reflectometer and emissometer, X-ray photoelectron spectroscopy, phase-modulated spectroscopic ellipsometry, atomic force microscopy and micro-Raman spectroscopy techniques. In order to study the thermal stability of the tandem absorbers, they were subjected to heat treatment (in air and vacuum) at different durations and temperatures. The tandem absorber deposited on copper substrate exhibited high solar selectivity in the order of 13-15 even after heat-treatment in air up to 500°C for 2 hrs. These tandem absorbers also exhibited high thermal stability (450°C) in air for longer durations (116 h). The onset of oxidation for the tandem absorber deposited on silicon substrates was 650°C, indicating a high oxidation resistance. The results of the present study indicate the importance of NbAlN/NbAlON/Si3N4 tandem absorber for high temperature solar selective applications.
 
Publisher Elsevier
 
Date 2008
 
Type Journal Article
PeerReviewed
 
Relation http://linkinghub.elsevier.com/retrieve/pii/S0927024807004229
http://nal-ir.nal.res.in/9720/
 
Identifier Barshilia, Harish C and Selvakumar, N and Rajam, KS and Biswas, A (2008) Spectrally selective NbAlN/NbAlON/Si3N4 tandem absorber for high temperature solar applications. Solar Energy Materials and Solar Cells, 92 . pp. 495-504.