A Solvent‐Free, Thermally Curable Low‐Temperature Organic Planarization Layer for Thin Film Encapsulation

Abstract

Thin film encapsulation (TFE) is an essential component to ensure reliable operation of environmentally susceptible organic light‐emitting diode‐based display. In order to integrate defect‐free TFE on display with complex surface structures, additional planarization layer is imperative to planarize the surface topography. The thickness of conventional planarization layer is as high as tens of µm, but the thickness must be reduced substantially to minimize the light leakage in smaller devices such as micro light‐emitting diodes. In this study, a thin—less than 2 µm—planarization is achieved via solvent‐free process, initiated chemical vapor deposition (iCVD). By adapting copolymer from two soft, but curable monomers, glycidyl acrylate (GA) and 2‐(dimethylamino)ethyl methacrylate, excellent planarization performance is achieved on various nano‐grating patterns. With only 1.5 µm‐thick iCVD planarization layer, a 600 nm‐deep trench polyurethane acrylate pattern is flattened completely. The TFE fabricated on planarized pattern exhibits excellent barrier property as fabricated on flat glass substrate, which strongly suggests that iCVD planarization layer can serve as a promising planarization layer to fabricate TFE on various types of complicated device surfaces.

Designing Organic and Hybrid Surfaces and Devices with Initiated Chemical Vapor Deposition (iCVD)

“…[138] Copyright 2022, Wiley-VCH and H) planarization by a low T g iCVD polymer (Section 13.4), Reproduced with permission. [139] Copyright 2023, Wiley-VCH .…”

“…Planarizing layers with a low curing temperature were designed using iCVD. [139] The iCVD p(GA-co-DMAEMA) copolymer used has a T g value below 25 °C. Hence, using an iCVD surface growth temperature of 25 °C or higher causes this copolymer to flow during the deposition.…”

“…Copyright 2023, Elsevier B.V. G) self-wrinkling over a patterned substrate (Section 13.3), Reproduced with permission [138]. Copyright 2022, Wiley-VCH and H) planarization by a low T g iCVD polymer (Section 13.4), Reproduced with permission [139]. Copyright 2023, Wiley-VCH .…”