Design and Fabrication of PDMS/Al₂O₃ Hybrid Flexible Thin Films for OLED Encapsulation Applications

Highly effective flexible thin film encapsulation (TFE) is significant and challenging for organic light-emitting diodes (OLEDs). In this work, the Al 2 O 3 film fabricated by the atomic layer infiltration (ALI) technique penetrates into the PDMS material to form PDMS/Al 2 O 3 hybrid flexible thin films for OLED encapsulation to prolong its lifetime. It was found that the penetrative depth and density of Al 2 O 3 in PDMS could be regulated by the pulse time of the ALI precursor and reached saturation. The penetration of the Al 2 O 3 film could not only enhance the barrier performance of PDMS/Al 2 O 3 hybrid films but also alleviate the interfacial stress between PDMS and Al 2 O 3 . As a result, 3 pairs of PDMS/Al 2 O 3 hybrid films with a water vapor transmission rate (WVTR) of 9.24 × 10 –5 g/m 2 /day measured at 25 °C/50% RH were successfully prepared. The hybrid films were applied as encapsulation layers for OLED devices, whose brightness remains more than 50% of the initial brightness, exhibiting great barrier properties. Finally, the relationships between the penetrative degree, inorganic layer thickness, and maximum stress of PDMS/Al 2 O 3 hybrid flexible films under different bending deformations were simulated and verified by the experiment. These results indicate the promising application of PDMS/Al 2 O 3 hybrid films prepared by ALI in OLED encapsulation and stretchable, wearable, and flexible devices.