Solar Energy Photoconversion

  • PDF / 1,156,246 Bytes
  • 2 Pages / 597.6 x 777.6 pts Page_size
  • 96 Downloads / 175 Views

DOWNLOAD

REPORT


L. Kazmerski, Chairman amorphous materials research and application, outlined his company's philosophy and future in the amorphous silicon solar cell arena. Ovshinsky said his company approached the amorphous solar cell development dealing with large area devices and a scaled-up technology from the beginning. Energy Conversion Devices' joint effort with Sharp Electronics in Japan will be in commercial production in early 1983, area, p-i-n processing 1 ft2 amorphous Si:H:F solar cells. These cells, according to Ovshinsky, have no degradation and have indicated better than 20-year lifetimes under accelerated lifetime testing. Energy Conversion Devices has developed, built and sold three amorphous Si

PAGE 8, MRS BULLETIN, NOVEMBER/DECEMBER 1982

multichamber cell production systems that continuously coat one foot wide flexible stainless steel ribbon with amorphous cells, with a 3 MW/yr production capability. Ovshinsky expects cells in the 11% - 12% range maximum for single junction devices, but over 30% for tandem cells which he says will represent no added cost over single cells. Ovshinsky demonstrated the large-scale production capabilities of his system with a slide of a 1,000 foot long, 1 foot wide tandem amorphous solar cell. Two contributed papers dealing with the thermal annealing of amorphous Si:H cells (M.K. Han, SUNY) and the characterization of a-Si:Sn:H alloys (D.L.Williamson, Colorado School of Mines and SERI) were also presented. The stability of electrodes in photoelectrochemical cells was discussed in an invited presentation by A. J. Bard of the University of Texas. Incorporation of silicides (Pt, Ir, Ru) and utilization of catalysts provide stable Si photoelectrodes. The status of amorphous hydrogenated Si electrodes was presented by G. S. Calabrese of M.I.T. Although cost considerations favor this material, photovoltages have been limited. Large area thinfilm CdSe electrochemical cells with efficiencies in excess of 6% were reported by R. D. Rauh of EIC Laboratories. Areas up to 400cm2 for these cells have been tested. Grain boundary limitations in polycrystalline Si cells formed the subject of a group of papers by P. E. Russell, S.E.R.I, E. S. Yang, Columbia University, J. I. Hanoka, Mobil Tyco, S. J. Fonash, Pennsylvania State University, W. F. Regnault, Semix Inc., and J. S. Song, Columbia University. The invited paper by Russell and Yang focused on the role of impurities - specifically

materials and devices

oxygen - on the electrical activity of the intergrain regions. Fonash reported that the degree of activation depends significantly upon the thermal and process history of the polysilicon. Hanoka reported an improvement in efficiency (from 8.4% to 9.5%) of hydrogen passivated EFG silicon. Antireflection coated ribbons exhibited efficiencies of up to 14% following hydrogen treatment. Semix reported on the differences in grain boundary behavior with structural and orientational properties. A model for polycrystalline Si photoconductivity was covered by J. S. Song. A near-commercialization photo