Effect of pretreatment on PET films and its application for flexible amorphous silicon solar cells

We proposed a low cost solution of flexible amorphous silicon solar cells on Polyethylene terephthalate(PET) polymer substrates deposited at low temperatures. PET films were firstly annealed both in the air and in vacuum at different temperatures, and the properties of PET films after annealing were evaluated. Then PET films were exposed to glow discharge Argon plasma in a standard PECVD system to improve their surface properties. The relationship between glow discharge parameters and the energy of Ar plasma were investigated by OES. After Ar plasma treatment, not only the surface morphology of PET but also the adhesion of the solar cell thin films to the PET substrates were improved. Finally, single junction a-Si solar cells with a p-i-n superstrate type were fabricated on PET/ITO substrates at low temperature of Ts=125°C, and an initial efficiency of 4.8% was obtained.