Absorber and emitter for solar thermo-photovoltaic systems to achieve efficiency exceeding the Shockley-Queisser limit

Abstract

We present theoretical considerations as well as detailed numerical design of absorber and emitter for Solar Thermophotovoltaics (STPV) applications. The absorber, consisting of an array of tungsten pyramids, was designed to provide near-unity absorptivity over all solar wavelengths for a wide angular range, enabling it to absorb light effectively from solar sources regardless of concentration. The emitter, a tungsten slab with Si/SiO(2) multilayer stack, provides a sharp emissivity peak at the solar cell band-gap while suppressing emission at lower frequencies. We show that, under a suitable light concentration condition, and with a reasonable area ratio between the emitter and absorber, a STPV system employing such absorber-emitter pair and a single-junction solar cell can attain efficiency that exceeds the Shockley-Queisser limit.

Analog of superradiant emission in thermal emitters

“…Nanophotonic control of thermal emission [1,2] has attracted significant recent interests because of potential applications in areas such as thermophotovoltaics [3][4][5][6][7][8], lighting [9], and radiative cooling [10,11]. From a fundamental physics perspective, with the capability to tailor lightmatter interactions, nanophotonic structures can enable thermal emission behaviors that are drastically different from those of conventional bulk emitters [12][13][14][15][16][17][18][19][20][21][22][23].…”

“…From a fundamental physics perspective, with the capability to tailor lightmatter interactions, nanophotonic structures can enable thermal emission behaviors that are drastically different from those of conventional bulk emitters [12][13][14][15][16][17][18][19][20][21][22][23]. For example, while blackbody emitters are typically considered to be incoherent with a total emission power limited by the Stephan-Boltzman law, nanophotonic emitters can be highly coherent [6,20,22] or have emission beyond the blackbody limit [4,19].…”

Enhancing far-field thermal emission with thermal extraction

“…Any actual macroscopic thermal body cannot emit more thermal radiation than a blackbody. The Stefan-Boltzman law provides an important theoretical foundation for much of the recent works aiming to design nanophotonic structures in order to tailor the spatial and spectral properties of far-field thermal emission [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] .…”

Integrated photonic crystal selective emitter for thermophotovoltaics

“…2, corresponding to 100% emittance between 1300 and 1771 nm, and zero emittance elsewhere. This property fully suppresses sub-bandgap losses and greatly reduces carrier thermalization, 47 yielding an ideal emission conversion efficiency η ideal ¼ 46.1%.…”