The profile optimization of periodic nano-structures for wavelength-selective thermophotovoltaic emitters

• Published in: International journal of heat and mass transfer Vol. 53; no. 23; pp. 5542 - 5551
• Main Authors: Chen, Y.-B., Tan, K.-H.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-11-2010; Elsevier
• Subjects: Applied sciences; Emittance; Emitters; Energy; Exact sciences and technology; Nanomaterials; Nanostructure; Natural energy; Optimization; Orthogonal arrays; Periodic nano-structure; Photovoltaic conversion; Rigorous coupled-wave analysis; Solar cells. Photoelectrochemical cells; Solar collectors; Solar energy; Solar thermal conversion; Spectral emittance; Taguchi method; Thermophotovoltaic; Thermophotovoltaics; Wavelength-selective; Wavelengths; Periodic nano-structure; Thermophotovoltaic; Rigorous coupled-wave analysis; Wavelength-selective; Taguchi method
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2010.06.051

This work demonstrates a systematic and efficient way of searching two-dimensional periodic nano-structures with wavelength-selective radiative properties appealing to thermophotovoltaic emitters. The orthogonal array from the Taguchi method benefits the optimization of structure depth, periods, and filling ratios among 1024 combinations. The spectral emittance from optimized structures is above 0.9 at wavelengths between 1.0 and 2.0
μm, but the emittance is below 0.2 at wavelengths between 2.0 and 4.0
μm. Furthermore, such spectral emittance characteristics can be kept for wide ranges of emission direction and either polarization. Representative emittance spectra from an example of convex rectangular structures are plotted and compared to those of concave structures in previous works. The comparison shows that radiative properties of convex structures are dominated by cavity resonances while those of concave structures are the interplay of multiple mechanisms. All numerical results are obtained from validated programs based on the rigorous coupled-wave analysis.