Dopant와 Host 물질의 변화에 따른 적색 유기발광다이오드의 특성 분석

Charactenzanon of Red Oigamc Ltght-emittiiiff Diodes with Various Dopant and Host Materials

Host-dopant system in Organic Light-Emitting Diode(OLED) is used to improve the electrical and optical performance of the device. Red OLED devices were fabricated using MADN and TCTA as the host materials, and rubrene and DCJTB as red dopant materials in the emitting layer. When MADN was used as a host material, luminous efficiency of rubrene doped device and DCJTB doped device were 9.83cd/A and 6.59cd/A which showed a significant difference. However, the red device used TCTA as host material showed luminous efficiency of 4.18cd/A and 4.45cd/A each. In EL spectrum, blue emission peak at 456 nm and red emission peak at 556nm (Rubrene) or 584nm (DCJTB) were appeared with similar intensity because TCTA has low LUMO energy level and high HOMO energy level. Recombination was occurred by direct tunneling of charge from function layers to dopant due to relatively large energy band gap of TCTA.