Current Status of Polycrystalline Thin-Film PV Technologies

In the past 18 months, thin-film solar cell technologies based on CdTe and CIS have made significant technical progress. Most of the improvements have occurred at the level of solar cells, modules, systems, and reliability testing in both CdTe and CIS. Total-area efficiencies of 14.7% for a thin-film CdTe solar cell deposited on a low-cost, sodalime glass fabricated by Golden Photon, Inc; was verified by NREL. Siemens Solar Industries has fabricated a world-record, aperture-area efficiency of 11.1% and a power output of 40.6 W for a thinfilm CIGSS module. Solar Cells, Inc. has fabricated a largearea, thin-film CdTe module with an aperture-area efficiency of 9.1% and power output of 61.3 W; Golden Photon, Inc., has also fabricated a power module with an aperture-area efficiency of 9.2% and power output of 31.0 W. Key research issues for CdTe and CIS are discussed in this paper. Several polycrystalline thin-film arrays based on CdTe and one based on CIGSS have been deployed worldwide. Stability data indicated by both thin-film CIS and thin-film CdTe modules and systems are encouraging. Many companies worldwide are actively pursuing early commercialization efforts based on both speciality products and power modules.