Low Pressure Organic Vapor Phase Deposition of Small Molecular Weight Organic Device Structures

Abstract

AbstractA new technique for the deposition of amorphous organic thin films, low pressure organic vapor phase deposition (LP-OVPD), was used to fabricate organic light emitting devices (OLEDs) and optically pumped organic lasers. The OLED consisted of a film of aluminum tris- (8 hydroxyquinoline) (Alq3) grown on the surface of a film of N'-diphenyl-N,N'-bis(3- methylphenyl)1–l'biphenyl-4–4'diamine (TPD). Growth on both glass and polyester substrates was accomplished and the resulting heterojunction devices were found to have a performance similar to conventional, small molecular weight OLEDs grown using thermal evaporation in vacuum. The LP-OVPD grown OLED has an external quantum efficiency of 0.40 ± 0.05% and a turn-on voltage of approximately 6V. The optically pumped organic laser consisted of a film of Alq3 doped with the laser dye, benzoic acid, 2-[6-(ethylamino)-3-(ethylimino)-2,7-dimethyl-3Hxanthen- 9-yl]-ethyl ester, monohydrochloride (Rhodamine 6G). The laser output was centered at approximately 610nm and the lasing threshold was 30μJcm−2. The rapid throughput of LP-OVPD and its use of low vacuum in a horizontal reactor demonstrate its potential to facilitate low cost, roll-to-roll deposition of organic films for many photonic device applications.