Barrier materials are required for encapsulating organic devices. A simple methodology based on organic passivation layer on a flexible substrate has been developed in this work. Stearyl stearate (SS) was directly coated over the flexible Surlyn film. The barrier films with SS passivation layer exhibited much lower water vapor transmission rates compared to the neat Surlyn films. Moreover, the effect of the process of deposition of organic passivation layer on the resultant water vapor properties of the barrier films was evaluated. The accelerated lifetime studies conducted on encapsulated organic photovoltaics showed that the passivation layer improved the device performance by several fold compared to the non-passivated barrier films. © 2014 AIP Publishing LLC.