Wavelength Selective Emitting Materials Using High-Temperature Photonic Structures
- PDF / 233,794 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 104 Downloads / 194 Views
1162-J02-03
Wavelength Selective Emitting Materials Using High-Temperature Photonic Structures Yong Sung Kim and Shawn-Yu Lin Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
ABSTRACT Recently, wavelength selective emitting materials have attracted extensive interest due to their potential of high optical-to-electricity conversion efficiency for thermal photovoltaic (TPV) cells and realizing high efficient incandescent light sources. A substantial increase in spectral control over thermal radiation and photon recycling can accomplish this objective by the development of high-temperature photonic structures (HTPS) that simultaneously suppress unwanted radiation and enhance emission in a desirable wavelength range. In this paper, we shall review the properties of HTPS as a wavelength selective emitter, the radiative energy transfer relation in real devices, and photon recycling scheme using wavelength selective filters. INTRODUCTION Recently, wavelength selective emitting materials have attracted extensive interest due to their potential applications for thermal photovoltaic (TPV) cells with high conversion efficiency and high efficient incandescent light sources. These objectives can be accomplished by the development of high-temperature photonic structures (HTPS) that simultaneously suppress unwanted radiation and enhance emission in a desirable wavelength range. An application of the wavelength selective high-temperature photonic structure is an absorber/emitter in a thermal photo-voltaic (TPV) system. A conventional TPV system converts heat differentials into electricity via photons. In TPV conversion, an intermediate absorber/emitter is placed in between a heat source and a solar cell. Photons with their energy below the band gap do not generate electron-hole pairs and merely contribute to heat loss. To achieve a better efficiency, blackbody radiation must be altered and matched to the band gap energy of a solar cell. A recent calculation predicts a maximum efficiency of 84% for a concentrated solar TPV system, assuming that perfect energy matching is achievable [1]. Blackbody radiation is the most fundamental form of thermal radiation. The temperature of a typical absorber/emitter is 1500K and the corresponding peak emission wavelength is at λ~2µm. The 3D metallic photonic crystal structure, as a thermal radiator, was proposed in 2003 [2, 3]. The structure itself is an emitter and, therefore, its intrinsic radiation properties are directly and locally influenced by the basic photon modes. By controlling the Bloch modes in a 3D photonic crystal, it enables to control radiation wavelength by structuring, to sharpen radiation spectral linewidth substantially as compared to that of a blackbody and to maintain the peak radiation wavelength while increasing the radiator’s temperature. Another application of the wavelength selective high-temperature photonic structure is the filament of an incandescent light source. Incandescent light sources have been domina
Data Loading...
