Noticia

The Group “III-V Semiconductors” of the Instituto de Energía Solar of the Universidad Politécnica de Madrid have set a world record in dual-junction solar cell efficiency with a photovoltaic device that converts 32.6% of the light impinging it into electricity.

The lattice-matched GaInP/GaAs dual-junction solar cell was designed and manufactured by the group led by Prof. Carlos Algora (IES-UPM, Spain) and independently measured at the calibration laboratory of Fraunhofer Institute of Freiburg (Germany). The 32.6% efficiency was measured under a concentrated light of 1026 suns while at 2873 suns the efficiency is still 31.1%. One sun is about the amount of light that typically hits Earth on a sunny day.

The new cell is a natural candidate for terrestrial concentrated photovoltaic modules, which use lenses or mirrors to focus sunlight onto the solar cells. The IES-UPM solar cell differs significantly from the previous world record holder dated of 2000 set at 31.0% at 300 suns by Fraunhofer Institute of Freiburg (Germany). The importance of the new record is not only in an increase of efficiency of 1.6% with regard to the previous record but also in the concentration level at which has been obtained (1026 suns now while the previous one was at 300 suns). As a rule of thumb, the higher the concentration the lower the resulting price of the generated electricity. The potential of the new record solar cell is highlighted when consider that after a development of about five years of concentrator photovoltaic systems based in this type of solar cell the cost analysis results in a solar electricity cost of about 5.5 c€/kWh while at present the cost of electricity in Spain (generated by all available sources: nuclear, oil, coil, gas, renewable…) is about 7.5 c€/kWh. The record solar cell represents a new step for improving the efficiency of the triple junction solar cells whose actual record at 40.8% was achieved under concentrating light of 300 suns by NREL (USA). Researchers of the Group of III-V Semiconductors of IES-UPM think that the proper integration of its dual junction in a triple junction solar cell could result in a device with efficiencies higher than 41% at 1000 suns.