Roadmap towards efficiencies over 40% at ultra-high concentrations (> 1000 suns)

High efficiency solar cells working under ultra-high concentrations (>;1000X) have been shown to be a promising solution to decrease the cost of PV electricity, increase the efficiency and circumvent the material availability restrictions for massive PV penetration. A detailed analysis of the limitations of our current triple junction solar cell (36.2% at 700X), in the quest to maximize efficiency at 1000X, shows that the main improvements to tackle are: a) implementation of a high band gap tunnel junction; b) increase the band gap of the top cell; c) fine current matching tune; d) enhancement of the front contact process. This constitutes our roadmap to reach an efficiency over 41%

Limiting efficiencies of GaAs solar cells

The limiting efficiencies of GaAs solar cells when used under concentrated sunlight are calculated. The benefits to be expected from applying techniques which restrict the angle of acceptance of the cell are determined. It is concluded that when the acceptance angle is restricted the emission of the luminescent photons and therefore the associated current loss are reduced. A limiting efficiency close to 39% results for concentration ratios of about 1000 suns AM1.5 direct. For lower concentration ratios, the limiting efficiency decreases if Auger recombination is also taken into account

Photovoltaic application of O-doped Wittichenite-Cu 3 BiS 3: from microscopic properties to maximum efficiencies

The electronic properties and the low environmental impact of Cu 3 BiS 3 make this compound a promising material for low-cost thin film solar cell technology. From the first principles, the electronic properties of the isoelectronic substitution of S by O in Cu 3 BiS 3 have been obtained using two different exchange-correlation potentials. This compound has an acceptor level below the conduction band, which modifies the opto-electronic properties with respect to the host semiconductor. In order to analyze a possible efficiency increment with respect to the host semiconductor, we have calculated the maximum efficiency of this photovoltaic absorber material.

Pressurized Irrigation Dealing with Water and Energy Efficiencies

En la conferencia se expone la situación en España de los riegos a presión considerando los condicionantes de escasez de agua y el precio de la energía.