Polymer light emitting diodes containing nanoparticle clusters for improved efficiency

✍ Scribed by Boris Riedel; Julian Hauss; Markus Aichholz; Andre Gall; Uli Lemmer; Martina Gerken

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 409 KB
• Volume: 11
• Category: Article
• ISSN: 1566-1199
• DOI: 10.1016/j.orgel.2010.04.017

✦ Synopsis

We realized polymer light emitting diodes (PLEDs) containing oxidic nanoparticle clusters between the emission layer and the cathode. Different PLEDs with SiO 2 and SiO 2 /TiO 2 nanoparticle blends were fabricated and characterized by electroluminescence (EL) and photoluminescence (PL) measurements. We found that the incorporation of pure SiO 2 leads to the most efficient devices boosting the efficiency up to a factor of about 4 at 60 mA=cm 2 . Characterization shows that this is not a scattering effect but rather due to enhanced internal quantum efficiency. The underlying mechanism is attributed to the nanoparticles creating a randomly nanopatterned cathode layer which in turn increases the electric field at the organic-cathode interface and the electron injection.