Interfacial and mechanical studies of a composite Ag–IZO–PEN barrier film for effective encapsulation of organic TFT

A composite silver–indium zinc oxide (Ag–IZO) layer is deposited on a polyethylene naphthalate (PEN) film by DC and RF sputter respectively. Tof–SIMS and XPS studies showed that an interface was formed when Ag has successfully plugged into the softer layer of IZO forming a composite Ag-IZO layer to achieve a water vapor transmission rate (WVTR) of ∼1.6 × 10−4 g/day/m2. Poly (3-hexylthiophene) (P3HT) based organic thin-film transistors (OTFT) encapsulated with the Ag–IZO–PEN film kept in glove box and ambient condition are tested and shown that this film is capable to provide the OTFT with adequate protection against moisture and oxygen for more than 3600 h. Mechanical bending tests on the Ag–IZO film also revealed that it has only 0.9% increase in sheet resistance after 10,000 cycles of bending which make this barrier film very suitable for encapsulation of flexible OTFT devices.