Flexible a-Si:H/nc-Si:H tandem thin film silicon solar cells on plastic substrates with i -layers made by hot-wire CVD

In this letter we report the result of an a-Si:H/nc-Si:H tandem thin film silicon solar mini-module fabricated on plastic foil containing intrinsic silicon layers made by hot-wire CVD (efficiency 7.4%, monolithically series-connected, aperture area 25 cm2). We used the Helianthos cell transfer process. The cells were first deposited on a temporary aluminum foil carrier, which allows the use of the optimal processing temperatures, and then transferred to a plastic foil. This letter reports the characteristics of the flexible solar cells obtained in this manner, and compares the results with those obtained on reference glass substrates. The research focus for implementation of the hot-wire CVD technique for the roll-to-roll process is also discussed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).