Effects of electron transport layer thickness on light extraction in corrugated OLEDs
Journal
Optics Express
Journal Volume
30
Journal Issue
11
Pages
18066-18078
Date Issued
2022
Author(s)
Abstract
This study reported the effects of electron transport layer (ETL) thickness on light extraction in corrugated organic light-emitting diodes (OLEDs) and each layer in OLEDs exhibited a periodical corrugated structure, which was determined by depositing thin films on a glass substrate with a nanoimprinted blazed grating structure. The insight is that light extraction in corrugated OLEDs significantly depends on the ETL thickness. Varying the ETL thickness changed the distribution of carrier recombination and led to exciton formation and optical interference, thereby resulting in different attribution of optical loss modes in OLEDs, which increased or even decreased light extraction and device efficiency. Trapped light extraction from the surface plasmon polariton (SPP) and waveguide (WG) modes was identified by splitting the light into transverse electric and transverse magnetic emissions. Thus, the contributions from the individual SPP and WG modes to the external quantum efficiency (EQE) were distinctly clarified by comparing the experimental results with the theoretical calculations. At the ETL thickness of 115 nm, the corrugated OLED exhibited a significantly enhanced (1.83-fold) EQE compared to the planar one due to the effective extraction of trapped light from the SPP and WG modes. The EQE was enhanced by 0.5%, wherein 0.39% came from the WG mode and 0.11% came from the SPP mode. © 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement
SDGs
Other Subjects
Efficiency; Electromagnetic wave polarization; Electron transport properties; Substrates; Surface plasmon resonance; Corrugated structures; Electron transport layers; External quantum efficiency; Layer thickness; Light extraction; Surface plasmon polariton modes; Surface plasmon waveguide; Thin-films; Trapped light; Waveguides modes; Organic light emitting diodes (OLED)
Type
journal article