New-type of ultralight flexible a-Si solar cell and its application on an airplane

An ultralight flexible a-Si solar cell fabricated on a transparent film substrate has been developed. High photoconductivity ( sigma ph) of 2*10/sup -5/ Omega /sup -1/ cm/sup -1/ and high photosensitivity ( sigma ph/ sigma d) of 1*10/sup 6/ were obtained with a-Si films deposited by H/sub 2/-dilution of SiH/sub 4/ on a transparent film substrate at 180 degrees C. Prebaking the transparent film substrate effectively reduced the impurity content of the a-Si film. A maximum output power of 550 mW and a power-to-weight ratio of 275 mW/g were obtained for an integrated-type a-Si solar cell with a size of 110*115 mm. As the first application of this flexible a-Si solar cell, a solar-powered airplane has been developed, and it completed a transcontinental flight across the United States. >