Fabrication of polymer LEDs by resonant infrared pulsed laser ablation

Abstract

Polymer light emitting diodes (PLEDs) have been fabricated in a vacuum environment by resonant infrared laser ablation of the light emitting layer. The light emitting polymer used was poly[2-methoxy-5-(2-ethylhexyloxy)- 1,4-phenylenevinylene] (MEH-PPV) and was deposited into the device structure ITO/MEH-PPV/Al. Fourier transform infrared (FTIR) spectroscopy confirmed that the laser-deposited polymer was not drastically altered by the deposition process. Laser-fabricated devices displayed similar properties such as electroluminescence spectra and IV characteristics as conventional spin-coated devices. The dependence of these device properties on laser fluence was investigated, and showed no strong dependency. Peak emission wavelengths of electroluminescence spectra were all within 10 nm of electroluminescence spectra of spin coated devices and showed only slight peak broadening. These results are technologically important in that shadow mask technology can be incorporated into this method to arbitrarily pattern substrates with light emitting polymers.