Improvements of Permeation Barrier Coatings Using Encapsulated Parylene Interlayers for Flexible Electronic Applications

Abstract

Abstract 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 × 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 × 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. magnified image