Controlled growth and spray deposition of silver nanowires for ITO‐free, flexible, and high brightness OLEDs

Abstract

The next generation of electronic devices will require low cost materials and processing techniques that are fully compatible with flexible substrates and large area applications. Silver nanowires are promising candidates for many applications and can be processed by various solution‐based large area deposition techniques. In this work, high aspect ratio silver nanowires were synthesized via a polyol reduction of silver nitrate in the presence of a metal‐salt and a capping agent. The grown nanowires were spray coated and simply planarized with inkjet printed PEDOT:PSS to produce smooth and high performance nanocomposite electrodes suitable for industrial applications. The nanocomposite electrodes exhibit figure of merit values (σDC/σOP) of about 60, higher than the values required for industrial use (>35). High conductivity with high optical transparency was achieved by controlling the aspect ratio of the nanowires and their concentration in the films. The highly conductive and transparent electrodes were utilized to fabricate organic light emitting diodes, which exhibited high luminance (∼ 7 × 103 cd m−2) and performance comparable to a “benchmark” ITO electrode. The results show that the combination of the nanocomposite materials, together with the solution based techniques could pave the way towards flexible, solution processable, low cost, and large area device applications.ITO‐free OLEDs fabricated using solution processed Ag NW/PEDOT:PSS nanocomposites as transparent conductive electrode. Improving the aspect ratio of the grown nanowires along with controlling their density in the films allow for highly conductive and transparent nanocomposite electrodes. These nanocomposite samples are utilized as a direct replacement for ITO in OLEDs.