HIGH EFFICIENCY MULTIJUNCTION PHOTOVOLTAIC SYSTEM

THE PROPOSED PROGRAM WOULD DEVELOP A MULTIJUNCTION PHOTOVOLTAIC SYSTEM BASED ON ACHIEVING SPECTRUM SPLITTING BY PASSING CONCENTRATED SUNLIGHT THORUGH A PRISM. THE OVERALL OBJECTIVE OF THE PHASE I EFFORT IS TO DEMONSTATE THE FEASIBILITY OF A PRISM/SPECTRUMSPLITTING MULTIJUNCTION CONCEPT FOR CONSTRUCTING A PHOTOVOLTAIC SYSTEM WITH AN AMO EFFICIENCY GREATER THAN 25% IN THE NEAR TERM AND ON THE ORDER OF 40% IN THE LONG TERM. THE PHASE I EFFORT WILL INVOLVE: DESIGN AND FABRICATION OF A PRISM TO SPLIT THE SOLAR SPECTRUM INTO TWO WAVELENGTH REGIONS APPROPRIATE FOR SI AND ALGAAS CELLS; FABRICATION AND CHARACTERIZATION OF A RED-ENHANCED SI CELL AND AN AL .27 GA .73AS CELL CAPABLE OF CONTRIBUTING TO THE SYSTEM EFFICIENCY 8.5% AND 16.5% RESPECTIVELY; DEMONSTRATION EXPERIMENTS TO SHOW THE FEASIBILITY OF ACHIEVING AN AMO EFFICIENCY OF 25% WITH SI AND ALGAAS CELLS USED WITH PRISM/SPECTRUM-SPLITTING; AND MODELING CALCULATIONS FOR A THREE-CELL SYSTEM. AT THE END OF PHASE I, IT IS EXPECTED THAT THE FEASIBILITY OF THE PRISM/SPECTRUM-SPLITTING APPROACH TO THE MANUFACTURE OF TWO OR THREE-CELL SYSTEMS, WITH SILICON AS THE LOW BANDGAP CELL, THAT EXHIBIT AN AMO EFFICIENCY GREATER THAN 25%. FINALLY, COMMERCIALIZATION OF THE TECHNOLOGY WOULD BE DONE IN PHASE III.