Device Physics of Thin-Film Polycrystalline Cells and Modules: December 6, 1993 - March 31, 1998

Research output: NRELSubcontract Report


This report describes work performed under this subcontract by Colorado State University (CSU). The results of the subcontract effort included progress in understanding CdTe and Cu(In1-xGax)Se2-based solar cells, in developing additional measurement and analysis techniques at the module level, and in strengthening collaboration within the thin-film polycrystalline solar-cell community. A majorpart of the CdTe work consisted of elevated-temperature stress tests to determine fabrication and operation conditions that minimize the possibility of long-term performance changes. Other CdTe studies included analysis of the back-contact junction, complete photon accounting, and the tradeoff with thin CdS between photocurrent gain and voltage loss. The Cu(In1-xGax)Se2 studies included work onthe role of sodium in enhancing performance, the conditions under which conduction-band offsets affect cell performance, the transient effects of cycling between light and dark conditions, and detailed analysis of several individual series of cells. One aspect of thin-film module analysis has been addressing the differences in approach needed for relatively large individual cells made withoutgrids. Most work, however, focused on analysis of laser-scanning data, including defect signatures, photocurrent/shunting separation, and the effects of forward bias or high-intensity light. Collaborations with other laboratories continued on an individual basis, and starting in 1994, collaboration was through the national R&D photovoltaic teams. CSU has been heavily involved in the structureand logistics of both the CdTe and CIS teams, as well as making frequent technical contributions in both areas.
Original languageAmerican English
PublisherNational Renewable Energy Laboratory (NREL)
Number of pages59
StatePublished - 1999

Bibliographical note

Work performed by Colorado State University, Fort Collins, Colorado

NREL Publication Number

  • NREL/SR-520-26315


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