A series of multilayer polymeric light-emitting diodes (PLEDs) containing an electron-transporting layer (ETL), that is tris(8-quinolinolato)- aluminum(III) (Alq) and 2,2′,2″-(1,3,5-phenylene)-tris[1-phenyl-1H- benzimidazole] (TPBI), were fabricated by doping fluorescent oligo(p-phenylene-vinylene)s (BIII and BV) and polymer derivatives (PBV) into poly(N-vinyl carbazole) (PVK). These PLEDs can be optimized by the design of multilayer device configurations (brightness increased 8-15 times by addition of ETL) and possess greenish electroluminescent (EL) spectra peaked about 500-540 nm. A remarkably high brightness of 56,935 cd/m2 with a power efficiency of 3.25 lm/W was obtained in the device of PVK:BVOC 8-OC8 (100:20)/Alq (60 nm/60 nm). It suggests that the emission mechanism (including the conjugated and excimer emissions of BVOC 8-OC8 emitters) originates from both of BVOC 8-OC8 and ETL (Alq and TPBI) by varying the concentration of chromophores and adjusting the thickness of ETL. The concentration effect of the emitters in PVK (i.e. PVK:BVOC8-OC8 = 100:5, 100:20, and 100:100 wt %) and the influence of the ETL (including its thickness) on the EL characteristics are also reported.
|Number of pages||15|
|Journal||Journal of Polymer Science, Part A: Polymer Chemistry|
|State||Published - 1 May 2006|
- Electron-transporting layer (ETL)
- Poly(N-vinyl carbazole) (PVK)