Electroluminescence of bipolar tetraphenylmethane-based molecular materials
Abstract
Bipolar p-TPAOXD and m-TPAOXD are both tetraphenylmethane- based isomeric compounds containing triphenylamine- substituted 1,3,4-oxadizaole moieties. Two are amorphous materials showing no melting or crystallization transition but only glass transition at 187 and 149 degree(s)C, respectively. Single-layer organic light-emitting devices based on p-TPAOXD or m-TPAOXD as active layer were fabricated via spin-casting method. With varied fabrication conditions (solvent, cathode material, and film thickness) devices with turn-on voltage as low as 4V, blue electroluminance with intensity of 1,700 cd/m2, and photometric efficiency larger than 0.7 cd/A can be achieved for p-TPAOXD. The luminance and photometric efficiency of the device containing m-TPAOXD are low (always less than 100 cd/m2 and 0.2 cd/A) as compared to those containing p- TPAOXD.
- Publication:
-
Organic Light-Emitting Materials and Devices V
- Pub Date:
- February 2002
- DOI:
- 10.1117/12.457488
- Bibcode:
- 2002SPIE.4464..291L