Sub-micro organic light emitting diode arrays defined by tip-induced resist hollow structures

Abstract

Fabrication of micro-nanoscaled organic light-emitting diodes (OLEDs) with uniformity and scalability has emerged as a promising technology in next-generation displays and light sources. Patterning polymer resist into well-defined structures is a crucial step in the fabrication of optoelectronic device arrays, especially for cost-effectively fabricating lithographical sub-micro resist structures. Atomic force microscopy (AFM) ploughing is promising for patterning high-resolution polymer resist structures owing to nanoscaled resolution, high controllability, with relatively low cost under flexible working conditions. However, the defects of structures resulting from polymer debris contamination or spin-coated film exfoliation in ploughing procedure limit their further application in fabrication of device arrays. Herein, lithographical poly(methyl methacrylate) (PMMA) resist patterns in micro-nanoscale with excellent reproducibility and uniformity are achieved via AFM mechanical ploughing at the optimized lithography conditions. Taking use of the isolated PMMA cavities as current channels, we fabricate prototype OLED arrays with pixels of 500 nm and 1 μm. This work paves the way for developing a tip-based mechanical lithography approach to fabricate micro-nanoscaled optoelectronic devices in a simple and low-cost way.