DEVELOPMENT OF HOT-WIRE CVD SILICON NIP THIN FILM SOLAR CELLS

摘要

The preparation of all-microcrystalline nip solar cells entirely prepared by hot-wire chemical vapourdeposition (HWCVD) on highly reflecting Ag/ZnO substrates was investigated. An efficiency of ηinitial = 7.0 % couldbe obtained, which to the best of our knowledge is the highest value obtained for an all-HWCVD μc-Si:H singlejunction nip solar cell. These cells show no decrease in efficiency after 1000 hours of light soaking. A very smalldecrease of the fill factor and the open-circuit voltage was even overcompensated by an increase of the short circuitcurrent density jsc, which is observed for light soaking exceeding 30 h. This increase in jSC is attributed to changes in the indium tin oxide TCO or the p/TCO interface due to air exposure and leads to an ηstable = 7.3 %. Further studies on the integration of such nip solar cell into an all-hot-wire amorphous-microcrystalline nipniptandem solar cell were successfully carried out, leading to as-deposited initial efficiencies of up to η = 8.2 %. Also for these tandem solar cells the increase of jSC is partially compensating the expected Staebler-Wronsky degradation of the amorphous top cell resulting in an efficiency ηstable?= 7.9%. Finally, the preparation of an a-Si:H/μc-Si:H/μc-Si:H-triple cell is demonstrated, with an initial efficiency of 8.3%.