Thermal stability of nano-structured selective emitters for thermophotovoltaic systems
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.
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| Format: | Thesis |
| Language: | eng |
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Massachusetts Institute of Technology
2013
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| Online Access: | http://hdl.handle.net/1721.1/78173 |
| _version_ | 1826211549833854976 |
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| author | Lee, Heon Ju, 1977- |
| author2 | Sang-Gook Kim. |
| author_facet | Sang-Gook Kim. Lee, Heon Ju, 1977- |
| author_sort | Lee, Heon Ju, 1977- |
| collection | MIT |
| description | Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012. |
| first_indexed | 2024-09-23T15:07:32Z |
| format | Thesis |
| id | mit-1721.1/78173 |
| institution | Massachusetts Institute of Technology |
| language | eng |
| last_indexed | 2024-09-23T15:07:32Z |
| publishDate | 2013 |
| publisher | Massachusetts Institute of Technology |
| record_format | dspace |
| spelling | mit-1721.1/781732019-04-11T10:39:17Z Thermal stability of nano-structured selective emitters for thermophotovoltaic systems Lee, Heon Ju, 1977- Sang-Gook Kim. Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Mechanical Engineering. Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012. Cataloged from PDF version of thesis. Includes bibliographical references (p. 97-103). A fundamental challenge in solar-thermal-electrical energy conversion is the thermal stability of materials and devices at high operational temperatures. This study focuses on the thermal stability of tungsten selective emitters for thermophotovoltaic (TPV) systems which are anticipated to enhance the conversion efficiency. Selective emitters, 2-D photonic crystals, are periodic micro/nano-scale structures that are designed to affect the motion of photons at certain wavelengths. The structured patterns, however, lose their structural integrity at high temperatures, which disrupt the tight tolerances required for spectral control of the thermal emitters. Through analytical studies and experimental observations, the failure modes of tungsten 2-D photonic crystal are indentified. There were four major mechanisms of thermal degradation by which micro/nano-scale structures change their geometry when heated: grain growth and recrystallization, oxidation, surface diffusion, and evaporation. A novel idea of flat surface tungsten photonic crystal (FSTPC) was proposed and was validated by theoretical modeling and by experiments. Pre-annealing or using single crystalline tungsten will prevent the grain growth. A thin layer of diffusion barrier will prevent oxidation and/or evaporation and maintain the optical performance. By filling in the micro/nano-scale cavities with a damascened IR transparent ceramic, the surface of the emitter will have negligible second derivative of the curvature, and thus eliminates the surface diffusion even at high temperatures. Accelerated tests on silicon-based 2-D photonic crystal show that the micro/nano-scale structures on the silicon surface survive for at least 100 hours at 400 °C, homologous temperature of 0.4, which is equivalent temperature of 1200 °C for tungsten. Based on a scale-accelerated failure model, the life time of the Flat Surface Tungsten Photonic Crystal (FSTPC) is estimated to be at least 40 years at 800 °C. by Heon Ju Lee. Ph.D. 2013-03-28T18:10:50Z 2013-03-28T18:10:50Z 2012 2012 Thesis http://hdl.handle.net/1721.1/78173 829740704 eng M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 103 p. application/pdf Massachusetts Institute of Technology |
| spellingShingle | Mechanical Engineering. Lee, Heon Ju, 1977- Thermal stability of nano-structured selective emitters for thermophotovoltaic systems |
| title | Thermal stability of nano-structured selective emitters for thermophotovoltaic systems |
| title_full | Thermal stability of nano-structured selective emitters for thermophotovoltaic systems |
| title_fullStr | Thermal stability of nano-structured selective emitters for thermophotovoltaic systems |
| title_full_unstemmed | Thermal stability of nano-structured selective emitters for thermophotovoltaic systems |
| title_short | Thermal stability of nano-structured selective emitters for thermophotovoltaic systems |
| title_sort | thermal stability of nano structured selective emitters for thermophotovoltaic systems |
| topic | Mechanical Engineering. |
| url | http://hdl.handle.net/1721.1/78173 |
| work_keys_str_mv | AT leeheonju1977 thermalstabilityofnanostructuredselectiveemittersforthermophotovoltaicsystems |