The EALD-Al2O3/CTPEN composite films with Al-O-C chemical bonding exhibit enhanced moisture barrier and mechanical properties for encapsulation

Encapsulation is a crucial technology for isolating and protecting moisture-sensitive materials. However, traditional organic-inorganic composite films often exhibit poor adhesion at the interface and high gas permeability, making stable operation difficult. In this work, an enhanced atomic layer deposition (EALD) method was used to uniformly deposit a layer of thickness-controlled alumina on a Polyethylene Naphthalate (PEN) film with oxygen-containing polar groups(CTPEN) on its surface, successfully producing a high-barrier composite film (EALD-Al 2 O 3 /CTPEN) with Al-O-C chemical bonds. The designed CTPEN film significantly enhanced the adhesion of alumina, thereby improving the performance of the composite film. Moreover, the mechanical properties of the composite film were significantly enhanced, with the elongation at break of EALD-Al 2 O 3 /CTPEN at 72 % being considerably higher than that of ALD-Al 2 O 3 /PEN at 44 %, and the tensile strength reaching 220 MPa. At the same time, EALD-Al 2 O 3 /CTPEN maintained excellent light transmission, exceeding 85 %. Humidity -sensitive resistors encapsulated with EALD-Al 2 O 3 /CTPEN exhibited stable operating performance in both air and humidity-sensitive environments, confirming the superior barrier properties of the composite film. This EALD-Al 2 O 3 /CTPEN composite layer holds promise as a prospective encapsulation layer for future flexible devices.