DuPont is developing Kapton colorless polyimide film for use as a flexible superstrate for cadmium telluride (CdTe) thin film photovoltaic (PV) modules. The film was used by Swiss research institute Empa to reach CdTe conversion efficiency of 13.8%. The efficiency is near to that of glass-based photovoltaics panels.
June 2, 2011 — DuPont is developing Kapton colorless polyimide film for use as a flexible superstrate for cadmium telluride (CdTe) thin film photovoltaic (PV) modules. The film was used by Swiss research institute Empa to reach CdTe conversion efficiency of 13.8%. The efficiency is near to that of glass-based photovoltaics panels.
Kapton film is over 100x thinner and 200x lighter than traditional PV glass, and is flexible. It enables solar cell manufacturers to produce products at higher speed and lower cost on roll-to-roll (R2R) deposition equipment. Installation or balance of systems (BOS) and shipping costs can also be cut with the film-based cells, particularly for building integrated photovoltaics (BIPV). Flexible CdTe cells could be rolled up and carried to an install site, rather than lifted with a crane, points out Robert G. Schmidt, new business development manager, Photovoltaics – DuPont Circuit & Packaging Materials.
Empa’s Laboratory for Thin Films and Photovoltaics has been working on developing and optimizing a low deposition temperature (<450C) process for high-efficiency CdTe solar cells on glass (15.6% efficiency) and polymer film (12.6% efficiency). Empa is currently exploring materials to further these efficiencies in this process. Empa’s laboratory head Dr. Ayodhya N. Tiwari noted that sourcing a transparent yet high-temperature-resistant film was difficult, but once they began working with the DuPont product, they were able to get the right combination of properties for higher efficiency with easier processing.
DuPont is accepting requests for evaluation samples of the Kapton colorless polyimide film for flexible CdTe superstrates. It expects to commercialization in 2012.
Additional Kapton technologies are in development for better efficiency and lifetime reliability, as well as lower costs, of photovoltaic modules. DuPont’s Kapton polyimide film combines electrical, thermal, chemical and mechanical properties to withstand extreme temperatures.
Empa will present a technical paper on this study at the 26th European Photovoltaic Solar Energy Conference and Exhibition September 5-9, 2011, in Hamburg, Germany.
DuPont Photovoltaic Solutions offers materials for the photovoltaics manufacturing industry. To learn more, visit http://photovoltaics.dupont.com.
Empa’s Laboratory for Thin Films and Photovoltaics performs R&D on high-efficiency thin film solar cells with emphasis on novel concepts for enhancing the performance of solar cells, simplifying the fabrication processes, and advancing device structures for next generation of more efficient and low-cost devices. Learn more at www.empa.ch/tfpv.