양자우물구조 유기발광다이오드에서 공진터널링현상에 의한 휘도효율 개선의 관찰

Abstract

In this study, a synchronized appearance of resonant tunneling and luminance is reported in quantum well-structured organic light-emitting diodes (OLEDs) when the tris 8-hydroxyquinolinato aluminium (Alq3, 30 nm) and metal-free phthalocyanine (H2Pc, 5 nm) layers are employed as green and blue emission layers, respectively. The current density (J)-voltage (V) characteristic showed "peak and valley" between 14.6 and 16 V with a ratio of 4.5, which is clear evidence of the resonant tunneling phenomenon. The luminance (L)-voltage (V) characteristic also showed synchronized behavior with the resonant type of the J-V characteristic. On the other hand, the "peak and valley" characteristic was not observed when the thickness of H2Pc was thicker than 5 nm, which means no resonant tunneling took place. In conclusion, we were successful in showing improved luminance efficiency in quantum well-structured organic light-emitting diodes (OLEDs) by the resonant tunneling phenomenon.