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Highly Robust, Flexible Top‐Emission Organic Light‐Emitting Diode Exhibiting Stable Performance under Infolding of Curvature Radius of 0.32 mm
Author(s) -
Jeong Hansol,
Kim Hyo-Min,
Kim Jeonggi,
Jeong Wonkyeong,
Jang Jin
Publication year - 2021
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.202100045
Subject(s) - oled , materials science , radius of curvature , parylene , curvature , optoelectronics , radius , diode , silicon nitride , bend radius , active matrix , light emitting diode , silicon , optics , thin film transistor , nanotechnology , composite material , polymer , bending , mean curvature , geometry , mathematics , computer security , layer (electronics) , mean curvature flow , physics , computer science
Flexible top‐emission organic light‐emitting diodes (TOLEDs) with a thin‐film encapsulation (TFE) are of increasing attention to improve the flexibility of foldable smartphone organic light‐emitting diode (OLED) displays. There are inevitable issues to achieve foldable display with smaller folding radius for the future portable display. Herein, the device flexibility is investigated with infolding and outfolding tests with the curvature radius from 2.5 to 0.32 mm. Parylene (1 μm)/silicon nitride (SiN x ) ( X nm)/parylene (1 μm)/SiN x ( X nm) ( X = 100, 70, 50, and 30 nm) of TFEs are applied on the TOLEDs. It is found that stable device performances can be achieved at the curvature radius of 0.32 mm after 100 000 cycles infolding testing when the SiN x thickness is 30 nm. The device has significant degradation upon outfolding of 5000 cycles at the same radius of 0.32 mm. Note that, the water vapor transmission rate (WVTR) of the TFT with 30 nm SiN x is higher than the TFE with thicker SiN x (e.g., 50 nm). The flexibility and WVTR can be much improved using four‐stacked TFE with 30 nm SiN x for foldable active‐matrix OLED displays.