Figure 1
(a) Example of a multi-layer structure that exhibits selective thermal emission that is nearly optimal for the spectral response of InGaAsSb PVs. (b) The spectral response (which has SI units of A/W) of InGaAsSb plotted against the thermal emission spectrum of the structure illustrated in (a) and the blackbody spectrum at 1700 K; these thermal emission spectra are divided by an arbitrary number (5 ⋅ 1010) to aid visualization against the spectral response function. (c) Plot of the product of the spectral response function of InGaAsSb with the thermal emission of the structure in (a) plotted against the thermal emission itself; these two functions are the integrands that give rise to the short circuit current and the incident power in a STPV system, respectively. See reference [8] for a more detailed discussion of these quantities and their relation to the STPV efficiency.
Figure 2
(a) Visible absorptivity/emissivity (blue line) of a multi-layered structure optimized for radiative cooling plotted alongside the AM1.5 solar spectrum, illustrating that this structure minimizes absorption of solar power; the AM1.5 spectrum is divided by an arbitrary number (1.4 ⋅ 109) to aid visualization. (b) IR emissivity (red line) of the multi-layered structure optimized for radiative cooling plotted alongside the transmissivity of the earth’s atmospheres, illustrating that this structure maximizes ambient thermal radiation and minimizes absorption of thermal radiation from the atmosphere. This simulated structure was inspired by reference [5], and code to reproduce these figures in WPTherml can be found in the Example Code for radiative cooling application section of this manuscript and in a Jupyter notebook that ships with our package [12].
Figure 3
Schematic of the three-layer structure as defined by the ‘structure’ dictionary above, illustrating the convention for the direction of incoming, reflected, transmitted, and emitted light with respect to the order in which materials and thicknesses are specified by the user.
Figure 4
Schematic illustrating the flow of data between the user, the multilayer class, and the data and function libraries of WPTherml. More details can be found in the WPTherml README documentation [11].