Photovoltaic Manufacturing Cost and Throughput Improvements for Thin-Film CIGS-Based Modules: Phase II Technical Report, July 1999 -- August 2000

Thin-film photovoltaics (PV) has expanded dramatically in the last five years, but commercial use remains limited by performance, cost, and reliability. Of all the thin-film systems, copper indium gallium diselenide (CIGS) has demonstrated the greatest potential for achieving high performance at a low cost. The highest-quality CIGS has been formed by multi-source co-evaporation, a techniquepioneered in this country by researchers at NREL. Multi-source co-evaporation is also potentially the fastest and most cost-effective method of CIGS absorber deposition. Global Solar Energy (GSE) has adapted multi-source co-evaporation of CIGS to large-area, roll-to-roll processing on flexible substrates, enabling several manufacturing and product capability advantages. Roll-to-roll processingenables a low-cost, automated continuous manufacturing process. Flexible substrates enable product application in unique, as well as traditional, areas. The primary objectives of the GSE Photovoltaic Manufacturing Technology (PVMaT) subcontract are to reduce cost and expand the production rate of thin-film CIGS-based PV modules on flexible substrates. Improvements will be implemented inmonolithic integration, CIGS deposition, contact deposition, and in-situ CIGS control and monitoring. Specific goals of the three-year contract are:; ? Monolithic Integration-Increase integration speed by developing high-speed, all-laser scribing processes that are more than 100% faster than the baseline process and offer clean, selective scribing; increase capacity and substantially reducemodule area losses by insulating materials with high accuracy into laser scribes.; ? Absorber Deposition-Increase absorber-layer deposition rate by 75% in the large-area, continuous GSE process, increasing throughput and reducing labor and capital costs. Integrate a parallel detector spectroscopic ellipsometer (PDSE) with mathematical algorithms for in-situ control of the CIGS absorber, enablingruns of over 300 meters of moving substrate, while ensuring uniform properties; enhance health and safety by reducing selenium waste generation through modifications to the reactor and Se delivery method.; ? Back Contact Deposition-Reduce back-contact cost and increase operation yield by using improved back-contact materials.;