Synthesis of Soluble Host Materials for Highly Efficient Red Phosphorescent Organic Light-Emitting Diodes.
New soluble host materials with benzocarbazole and triphenyltriazine moieties, 11-[3-(4,6-diphenyl-[1,3,5]triazin-2-yl)-phenyl]-11H-benzo[a]carbazole and 11-[3'-(4,6-diphenyl-[1,3,5]triazin-2-yl)-biphenyl-4-yl]-11H-benzo[a]carbazole, were synthesized for highly efficient red phosphorescent organic light-emitting diodes (PHOLED). Hole-transporting benzocarbazole moiety and electron transporting triphenyltriazine moiety, which are severely twisted each other enhance the solubility of those materials in common organic solvent. The improved solubility from this molecular design could be due to a reduced π-π stacking interaction, which gives a very uniform film morphology after spin coating of those materials. As a result, we obtained highly efficient soluble PHOLEDs combined with an evaporated blue common layer structure. The resultant red PHOLED exhibited the maximum current efficiency as well as external quantum efficiency values up to 23.7 cd/A and 19.0%.
Organic Electronic Materials Laboratory, Department of Information Display, Kyung Hee University , Dongdaemoon-Gu, Seoul 02447, Republic of Korea.
Min Chul
MC
Suh
Organic Electronic Materials Laboratory, Department of Information Display, Kyung Hee University , Dongdaemoon-Gu, Seoul 02447, Republic of Korea.
So-Ra
SR
Park
Organic Electronic Materials Laboratory, Department of Information Display, Kyung Hee University , Dongdaemoon-Gu, Seoul 02447, Republic of Korea.
Ye Ram
YR
Cho
Organic Electronic Materials Laboratory, Department of Information Display, Kyung Hee University , Dongdaemoon-Gu, Seoul 02447, Republic of Korea.
Dong Heon
DH
Shin
Organic Electronic Materials Laboratory, Department of Information Display, Kyung Hee University , Dongdaemoon-Gu, Seoul 02447, Republic of Korea.
Pil-Gu
PG
Kang
Organic Electronic Materials Laboratory, Department of Information Display, Kyung Hee University , Dongdaemoon-Gu, Seoul 02447, Republic of Korea.
Dong A
DA
Ahn
Organic Electronic Materials Laboratory, Department of Information Display, Kyung Hee University , Dongdaemoon-Gu, Seoul 02447, Republic of Korea.
Hyung Suk
HS
Kim
Central Research Institute , KISCO, 69, Yangcheon-ro 75-gil, Gangseo-gu, Seoul 07537, Republic of Korea.
Chul-Bae
CB
Kim
blue common layer; cross-linked HTL; organic light-emitting diodes; relative current density; solution processed red PHOLED