Thin-film photovoltaic partnership -- CIS-based thin film PV technology: Final technical report, September 1995--December 1998

Abstract

PrefaceSiemens Solar Industries (SSI) has pursued the research and development of CuInSe 2 -based thin film PV technology since 1980 (1). SSI began a 3-year, 3 phase cost-shared subcontract (No. ZN-1-19019-5) on May 1, 1991 with the overall project goal of fabricating a large area, stable, 12.5% aperture efficient encapsulated CIS module by scaleable, low-cost techniques on inexpensive substrates. At the start of this subcontract SSI had demonstrated a 14.1% efficient 3.4 cm 2 active-area cell, unencapsulated integrated modules with aperture efficiencies of 11.2% on 940 cm 2 and 9.1% on 3900 cm 2 , and an encapsulated module with 8.7% efficiency on 3883 cm 2 (verified by NREL). Subcontract accomplishments included demonstration of encapsulated module efficiencies that were at that time the highest reported minimodule efficiencies for any thin film technology (encapsulated 12.8% efficient mini-module on 68.9 cm 2 and an NREL-verified 12.7% efficient unencapsulated circuit on 69 cm 2 with a prismatic cover), demonstration of a champion large area (3860 cm 2 ) encapsulated module efficiency of 10.3% (verified by NREL) that was the first thin film module of its size to exceed the 10% efficiency level, and delivery to NREL of a one kilowatt array of large area (~3890 cm2 ) approximately 30 watt modules (2).The primary objective of this subcontract (#ZAF-5-14142-03) is to establish reliable high-throughput, high-yield thin film deposition processes in order to make CIS a viable option for the next generation of photovoltaics. The primary goals for the project are to deliver a champion prototype 13% efficient large area module and to deliver sets of modules in 1 kW arrays composed of steadily increasing efficiency, reaching 1 kW of 12% efficient large-area modules by the end of the third year, demonstrating performance as well as commercial viability. This focus on sets of high-performance modules as deliverables reflects SSI's commitment to demonstrating a reliable low-cost product. This document is the final subcontract report on progress toward these objectives and goals through the three-year period of this subcontract, September 1995 through December 1998. AcknowledgmentsSiemens Solar Industries wishes to acknowledge the contributions of the following people and organizations. SummaryMultinary Cu(In,Ga)(Se,S)2 absorbers (CIS-based absorbers) are promising candidates for reducing the cost of photovoltaics well below the cost of crystalline silicon. The primary objective of this subcontract (#ZAF-5-14142-03) is to establish reliable high-throughput, high-yield thin film deposition processes in order to make CIS a viable option for the next generation of photovoltaics. The primary goals for the project are to deliver a champion prototype 13% efficient large area module and to deliver sets of modules in 1 kW arrays composed of steadily increasing efficiency, reaching 1 kW of 12% efficient large-area modules by the end of the third year, demonstrating performance as well as commercial viability. A major contract wor...