Low-Cost strategy for processing hierarchical surface textures on PET foils with modified wetting behavior and increased outcoupling efficiency for OLEDs

Research output: Contribution to book/conference proceedings/anthology/reportConference contributionContributedpeer-review

Contributors

Abstract

Nature provides many examples of surface structures with multiple functionalities. Some of those, such as light management and self-cleaning, are of interest for increasing the efficiency of optoelectronic devices, such as OLEDs, and for adding new surface functions. However, mimicking and transferring these textures to polymers over large areas often requires complex processes at high costs. Here, we demonstrate a low-cost strategy to fabricate hierarchically textured polyethylene terephthalate (PET) films by plate-to-plate hot embossing. Laser-machined stainless-steel plates with doublescaled hole-like textures were used as master for hot embossing. The larger structure with a period between 30 µm and 70 µm and depths up to 8 µm was produced by direct laser writing (DLW), whereas the smaller structure featuring a period of 3 µm at a depth up to 2 µm was fabricated by direct laser interference patterning (DLIP). The textured surfaces of stainless steel were then molded onto PET films at a pressure of 42 MPa and a temperature of 85°C using a hydraulic press. Topographical characterization was performed by confocal microscopy and scanning electron microscopy. Experiments have shown an increased static water contact angle up to 105°. Furthermore, the hierarchically microtextured foils were studied as out-coupling layers in OLEDs, showing a potential increase in device efficiency of up to 57%. The results thus indicate a good suitability of the developed surfaces for use in highly efficient OLEDs with easy-to-clean properties.

Details

Original languageEnglish
Title of host publicationLaser-based Micro- and Nanoprocessing XVI 2022
Pages46
Volume2022
Edition11989
Publication statusPublished - 4 Mar 2022
Peer-reviewedYes

Publication series

SeriesProceedings of SPIE
ISSN0277-786X

External IDs

Scopus 85131225787
Mendeley 5d19f3a2-130a-3921-a0d0-5aa83a85df41
ORCID /0000-0002-4112-6991/work/142254775

Keywords

Keywords

  • Direct Laser Writing, Direct Laser Interference Patterning, OLED, Polymer, Wetting Behavior, Hot Embossing

Library keywords