Flexible high barrier materials are needed for the use of future PV module technologies. R2R processes playa key roll for the production of e.g. a-Si, !-Ic-Si, CIS, CIGS or CdTe modules. The requirements for such flexible high barrier materials are very demanding. Permeation values as low as 10-5 g/m2 day for water vapor transition (WVTR) and respectively 10-5 cm3/m2 day atm for oxygen transition (OTR) are needed. The basic way to produce such materials is combining oxide layers (e.g. AIOx, SiOx) and barrier coatings with suitable polymer substrates.

Photochemical methods were developed to obtain a variation of the refractive index in aromatic polymer surfaces and a change in the photoluminescence characteristics of phenylene-vinylene-based polymers. Films of aromatic polymers, among them polystyrene (PS), poly(2-vinylnaphthalene) (PVN) and derivatives of poly(-phenylene-vinylene) (PPV) were UV irradiated in the presence of gaseous hydrazine (N2H4). The photoreaction led to a strongreduction of the refractive index of the polymers due to a hydrogenation of the aromatic units. In the case of PPV, we observed reductive photobleaching. This new technique was employed to produce photogenerated patterns in PPV. The results are compared to oxidative bleaching.

Photochemical methods were developed to obtain a variation of the refractive index in aromatic polymer surfaces and a change in the photoluminescence characteristics of phenylenevinylene-based polymers. Films of aromatic polymers, among them polystyrene (PS), poly(2-vinylnaphthalene) (PVN) and derivatives of poly(p-phenylene-vinylene) (PPV) were UV irradiated in the presence of gaseous hydrazine (N2H4). The photoreaction led to a strong reduction of the refractive index of the polymers due to a hydrogenation of the aromatic units. In the case of PPV, we observed reductive photobleaching. This new technique was employed to produce photogenerated patterns in PPV. The results are compared to oxidative bleaching.

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