Improvements of permeation barrier coatings using encapsulated parylene interlayers for flexible electronic applications

A multilayer barrier structure composed of silicon nitride, silicon oxide, and encapsulated parylene on a polycarbonate substrate has been investigated for flexible electronic applications. The organic buffer is commonly used as the smoothing, strengthening and defect-decoupling layer. However, a lateral leakage problem was observed in the organic interlayer, and resulted in increased permeation and poor adhesion between organic and inorganic layers. It was found that an encapsulated, thermal-treated parylene interlayer can be used to efficiently reduce the water vapor and oxygen permeation. After 75 d, the water vapor transmission rate (WVTR) can reach 2.5 x 10(-7) (g. m(-2)) d(-1), as calculated by the calcium test. After being flexed for 5 000 times, the WVTR value almost keeps around 2.1 x 10(-6) (g.m(-2)) d(-1). The performance of the proposed multilayer barrier structure has a high potential for flexible solar cell and organic light-emitting diode applications.