Improvement of barrier performance in thin film encapsulation for organic light-emitting diodes by a prior planarization process

The organic/inorganic hybrid barriers were fabricated to encapsulate the organic light-emitting diodes. Al 2 O 3 as inorganic layer was deposited by atomic layer deposition (ALD) and polydimethoxysilane (PDMS) as organic layer was prepared by the spin-coating process. It was found that the optimized encapsulation structure with a prior planarization process had a better barrier performance with a lower water vapor transmission rate improved effectively from 4.95 × 10 −1 gm −2 day −1 of Al 2 O3/PDMS films to 7.30 × 10 −3 gm −2 day −1 of the hybrid PDMS/Al 2 O 3 /PDMS films at 60 °C and a relative humidity of 90% and a longer luminance decay time. These improvements were attributed to the surface planarization of encapsulation basement including the coverage of particles by the prior spin-coating process, reducing the defects of inorganic film in process, and the hydrophobic surface of the outermost polymer lowering the adsorption of water vapor.