The Polyhedral Specular Reflector: A Spectrum-Splitting Multijunction Design to Achieve Ultrahigh ( >50%) Solar Module Efficiencies

SiNx/Cu Spectral Beam Splitting Films for Hybrid Photovoltaic and Concentrating Solar Thermal Systems

“…Further, Wang et al 13 designed a multilayer SBS film consisting of 13 layers and reported an average transmittance of 72.1% and a reflectance of 27.9% in the wavelength range of 250–2500 nm. In the past decade, various tandem multilayer films, such as SiO 2 /TiO 2 , 14 Nb 2 O 5 /SiO 2 , 15 , 16 SiO 2 /Ta 2 O 5 , 17 Ge/SiO 2 , 18 SiN x /SiO 2 , 19 and Ge/Nb 2 O 3 /Na 3 AlF 6 , 10 have been utilized in hybrid CPV/ST or PV/CST systems. However, such coatings require strict control of the film thickness and the superimposition of multiple layers of various materials, which increase the complexity of processing SBS films.…”

Simulation and partial prototyping of an eight‐junction holographic spectrum‐splitting photovoltaic module

“…Notably, Bragg reflectors are commonly used as spectrum‐splitting optical elements. They can be designed to have sharp cutoffs in reflection or transmission to effectively separate spectral bands without overlap, similar to tandem multijunctions in which incident light to subsequent cells is filtered by the sharp absorption edges of higher bandgap cells . However, depositing many dielectric layers of precise thickness is time‐consuming and costly.…”

DataSheet1.docx

“…The total modeled efficiency of the multijunction cell with a 100x PLSC was determined by a modified detailed balance calculation and is described in the Supplementary Material (Warmann et al, 2017;Eisler et al, 2019). First, the light transmission, reflection, and absorption of the PLSC was calculated using the open-source optical simulation software OpenFilters (Larouche and Martinu, 2008), which uses the transfer matrix method to determine the Fresnel coefficients of a planar multilayer stack.…”

“…This combined calculation accounts for the quantum dot losses, escape losses, and reabsorption losses. The modeled power generated by each subcell is determined by a modified detailed balance calculation that uses the external radiative efficiency (ERE) and fraction of ideal short circuit current to more realistically estimate the photovoltaic conversion losses (Warmann et al, 2017;Eisler et al, 2019). Here, we assumed EREs of 5% and 1% and fraction ideal current of 90% and 96% for the InGaP and Si subcells, respectively, as based on the current records (Warmann et al, 2017;Green et al, 2022).…”

“…Though there have been significant advancements in solar cell efficiency, the deployment of high efficiency photovoltaic designs (>30%) has been decreasing over the last decade (Wiesenfarth et al, 2017). This is because these high efficiency designs rely on costly and complex concentrating multijunction designs, wherein concentrating optics are used with multiple solar absorbers that absorb different parts of the solar spectrum to both convert more of the spectrum and minimize thermalization losses (Imenes and Mills, 2004;King et al, 2012;Polman and Atwater, 2012;Eisler et al, 2019). The cells in these multijunction designs, III-V materials, are costly to fabricate-a 28% efficiency single junction GaAs cell is modeled as $69/W (Horowitz et al, 2018).…”