OVERVIEW OF THIN FILM SILICON SOLAR CELL AND MODULE DEVELOPMENTS AT OERLIKON SOLAR

摘要

High initial efficiencies of 10.6 % could be achieved for 1 cm~2 amorphous silicon single-junction p-i-n solar cells of 0.20 μm thick i-layer deposited on TCO from Asahi U type (SnO_2) in small single-chamber R&D KAI-M reactor. Such an i-layer thickness has been found to be a good compromise between current loss and reduced light-soaking effect leading to a high stabilized efficiency of 8.6 % for this TCO. Incorporating such cells in 10 × 10 cm~2 mini-modules aperture efficiencies of initial 9.8% and stabilized ones of 8.0% have been realized. Using the commercial available TCO from AFG still leads to high initial mini-module aperture efficiencies of 9.1% and stabilized efficiencies of 7.6%. This a-Si:H deposition process is successfully transferred to industrial size substrates of 1.4 m~2 area. Independently measured by the ESTI Laboratories of the JRC (ISPRA) initial module powers of 110.6 W using a commercial TCO front AFG and, recently, 112.4 W using in-house developed LPCVD front ZnO have been reached. For both modules our in-house LPCVD ZnO layers have been applied as back contact. In a test production series of 1.4 m~2 unlaminated amorphous modules deposited on AFG a high production yield of over 96% could be achieved at an average output power of 107.6 W. Laminated modules passed successfully the damp-heat, the high voltage and thermal cycling tests which have been performed by the TUV Rheinland. Combining our amorphous and microcrystalline processes to micromorph tandems resulted in initial cell efficiencies over 10 % showing relative degradation rates of 9% for bottom limited test cells.