Synthesis and Electroluminescence Property of Anthracene Green Fluorescent Derivatives Based on Optimized Side Groups

Molecular size of OLED emitting materials is nano-metric size and when it is applied to the electric field it emits the light based on the energy conversion result. As new green fluorescent emitters, N,N,N',N'-Tetra-m-tolyl-anthracene-9,10-diamine (m-Me-TAD) and N,N,N',N'-Tetra-p-tolyl-anthracene-9,10-diamine (p-Me-TAD) were synthesized and the properties were evaluated. In solution state, photoluminescence (PL) maximum wavelength is 517 nm for m-Me-TAD and 529 nm for p-Me-TAD. In electroluminescence (EL) spectra, EL maximum wavelength of m-Me-TAD is 518 nm and p-Me-TAD is 533 nm. The doped device using m-Me-TAD as green fluorescent dopant exhibited current efficiency (CE) of 17.41 cd/A and external quantum efficiency (EQE) of 7.41%. The doped device with p-Me-TAD was optimized in order to achieve a green OLED with high efficiency.

Synthesis and Electroluminescence Property of New Hexaphenyl Benzene Derivatives Including Emitting Core for OLED

Three new emitting compounds of 5P-2TPA, 5P-2An and 5P-2Py for OLED based on hexaphenyl benzene moiety were synthesized. Physical properties were systematically examined by the change of the substitution groups of the synthesized materials. Photoluminescence (PL) spectrum of the synthesized materials showed maximum emitting wavelengths of about 437∼488 nm in solution state and 457∼516 nm in film state, indicating blue emission color. OLED devices were fabricated by the synthesized compounds using vacuum deposition process as an emitting layer. Device structure was ITO/2-TNATA 60 nm/NPB 15 nm/EML 35 nm/TPBi 20 nm/LiF 1 nm/Al 200 nm. External quantum efficiencies and CIE values of 5P-2TPA, 5P-2An and 5P-2Py were 3.34, 1.06 and 2.06% and (0.14, 0.12), (0.23, 0.45) and (0.24, 0.45), respectively. The three compounds exhibited thermal stablility with high Td of 426 °C, 449 °C and 467 °C.