A substrateless, flexible, and water-resistant organic light-emitting diode

TL;DR

This paper presents a novel ultrathin, flexible, and water-resistant OLED with embedded barriers that ensure stability in harsh environments, enabling new applications in wearables and bioimplants.

Contribution

The authors develop a 12 μm thick OLED with conformal barriers made of parylene-C and metal oxides, achieving unprecedented stability and robustness.

Findings

Stable in water and cell media for weeks

Endures repeated bending and postprocessing

Maintains performance under harsh conditions

Abstract

Despite widespread interest, ultrathin and highly flexible light-emitting devices that can be seamlessly integrated and used for flexible displays, wearables, and as bioimplants remain elusive. Organic light-emitting diodes (OLEDs) with $\mu$m-scale thickness and exceptional flexibility have been demonstrated but show insufficient stability in air and moist environments due to a lack of suitable encapsulation barriers. Here, we demonstrate an efficient and stable OLED with a total thickness of $\approx$12 $\mu$m that can be fully immersed in water or cell nutrient media for weeks without suffering substantial degradation. The active layers of the device are embedded between conformal barriers formed by alternating layers of parylene-C and metal oxides that are deposited through a low temperature chemical vapour process. These barriers also confer stability of the OLED to repeated bending and to extensive postprocessing, e.g. via reactive gas plasmas, organic solvents, and photolithography. This unprecedented robustness opens up a wide range of novel possibilities for ultrathin OLEDs.