Multijunction solar arrays for space and terrestrial applications

Photovoltaic conversion of the solar energy is the most prospective direction of the renewable power engineering. Solar arrays ensure power supply of spacecrafts and are gaining increasingly more application on the Earth. In the majority of developed countries, laws on state support of the “green” power engineering assisted in a substantial increase of power of the solar photovoltaic systems have been adopted. The main barrier to increasing the terrestrial solar photovoltaics development rates is a relatively high cost of the “solar” electric power. The ways for reducing the cost are the rise of the efficiency of power systems and the reduction of the material consumption for arrays based on multijunction solar cells. Results of multijunction solar cells and modules developments for space and terrestrial solar arrays are discussed in the article. In the last years, a significant experience on creation of multijunction solar cells was accumulated. Cascade solar cells and solar photovoltaic installations on their base with sunlight concentrators have been developed. At present, the terrestrial cascade solar cell efficiency exceeds 45%, which is substantially higher than that in conventional Si and thin-film solar arrays. The cascade solar cell efficiency increase has been achieved at the expense of “splitting” the sunlight spectrum into several intervals by the solar cell semiconductor structure fulfilling more effective photon energy conversion of each of these intervals in a definite parts of this structure. It is shown that multijunction solar cells provide the highest efficiency and they are the basic components of space arrays. Multijunction solar cells provide the highest conversion efficiency of concentrated sunlight as well. It opens prospects for decreasing the solar cell area and cost proportionally to the sunlight concentration. Developed concentrated photovoltaic installations are promising for wide applications in the high scale terrestrial solar photovoltaic energetics.