| 초록 |
Efficiency of polymer light-emitting diodes(LEDs) can depend upon the heat treatment condition and procedure. We have tried thermal annealing at the temperature above Tg of the emissive polymer, poly[2-methoxy-5-(2’-ethly-hexyloxy)-1, 4-phenylene vinylene] (MEH-PPV), before and after Al deposition respectively, in ITO/MEH-PPV/Al structure. An anomalous semiconducting behaviors of unannealed device can be screened by appropriate heat treatments. The annealing treatment after Al deposition also makes the EL efficiency enhanced by two orders and reduce the operating voltage about 40%. The high temperature annealing after Al deposition can enhance the interface characteristics between the emissive polymer and the metal cathode. Post-deposition annealing only without pre-deposition annealing is the most appropriate heat treatment.
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