An organic electroluminescent device with a molecularly doped polymer hole transport layer

✍ Scribed by Takashi Uemura; Nobuyuki Okuda; Hiroya Kirmura; Yasuko Okuda; Yoshinobu Ueba; Tuguru Shirakawa

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 125 KB
• Volume: 8
• Category: Article
• ISSN: 1042-7147
• DOI: 10.1002/(sici)1099-1581(199707)8:7<437::aid-pat669>3.0.co;2-s

✦ Synopsis

Electroluminescent (EL) devices have been fabricated using four different polymers with different glass transi

as a hole transport layer and tris(8-hydroxyquinoline) aluminum (Alq 3 ) as an emitting layer. It was found that the higher the T g of the polymer, the longer the lifetime of the device. From observations of TPD-doped polymer films with optical microscope and atomic force microscope, dispersing TPD in the polymers was found to suppress the crystallization that causes the roughness of the film surface. It was also observed that the higher the T g of the host polymers, the more difficult TPD crystallization was. The property of the EL device with polyethersulfone (PES) dispersed with TPD was also investigated. The lifetime of EL device with the TPD doped PES film was improved more than five times at a current density below 10 mA/cm 2 compared with the device with a conventional TPD hole transport layer.