Ultra-High Concentrator Photovoltaic (UHCPV) designs with up to more than 6000× geometrical concentration and optical efficiency of 80% are demonstrated in this paper by means of ray tracing simulations. These are developed based on Cassegrain-Koehler concentrators [Opt. Lett. 41(9), 1985 (2016)], with four pairs of paraboloid-hyperboloid mirrors and a central receiver composed of four Cartesian ovals of revolution. Designs at different geometrical concentrations are analyzed based on their aspect ratios (F-number). The most compact designs exhibit highest optical efficiencies. Moreover, a 3015× geometrical concentration one-cell prototype, made of aluminum and PMMA (poly(methyl methacrylate)), is fabricated and characterized indoors, achieving an effective concentration of 938 suns. This represents the CPV module with the highest geometrical concentration that has been experimentally investigated that could be found in the scientific literature.
The dielectric constant and loss were measured at several frequencies and temperatures for red mercuric iodide. The equivalent circuits for the sample, before and after a direct bias has been applied for a long time, are discussed. Complex impedance and loss tangent plots versus frequency and temperature show a contact barrier formation after long time polarization. Results are discussed in terms of gamma radiation detector performance.
Abslmd. Large changes of conductivity QCCUT in annealed pyrolytic SnOz films when irradiated with ulvaviolet radiation under ambient conditions. We have found that this effect is due to chemisorption-photodorption of oxygen following an Elovich-type kinetics, and hat chemisorption pmceeds by the transfer of electrons through a potential barrier.
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