It means that intermolecular distance in film state was closed, and intermolecular π-π* interaction was WH-4-023 solubility dmso increased because of no bulky side group. However, 5P-VTPA and 5P-DVTPA having bulky side group of aromatic amine moiety had slightly red-shifted with 5 to 15 nm in film state. 5P-VTPA including diphenyl amine group in solution state showed large red shift of 46 nm in emission wavelength compared to 5P-VA having only alkyl amine and dimethyl amine (see Table 1). DSC and TGA analyses to determine the thermal properties of the synthesized molecules Autophagy Compound Library datasheet were carried out (see Table 1). High T g and T d values indicate that the morphology of the material will not easily be changed by the high temperatures generated during

the operation of OLED devices and are closely correlated with long OLED device life-times [17, 18]. Two compounds showed high T g of 108°C and 110°C and high T d of 448°C and 449°C. Comparing on T m and T d of three compounds, two compounds having prevented molecular packing had the slightly decreased T m and the increased T g and T d. The

increased T g and T d can be interpreted by the increased molecular weight. Energy levels of three synthesized compounds such as HOMO, LUMO, and bandgap were estimated by ultraviolet photon spectroscopy of HDAC inhibitor AC-2 and optical absorption spectroscopy (see Table 2). 5P-VA had HOMO and bandgap values of -5.50 and 2.99 eV, respectively. 5P-VTPA and 5P-DVTPA showed HOMO values of -5.65 and -5.60 eV and bandgap values of 2.95 and 2.89 eV, respectively. Bandgap was decreased and emission wavelength was red-shifted according to the change from alkyl amine side group

to aromatic amine side group. Table 2 EL performance of multilayered devices with the synthesized compounds at 10 mA/cm 2 Compound Volt (V) Current efficiency (cd/A) Power efficiency (lm/W) EQE (%) CIE ( x , y) EL maximum HOMO (eV) LUMO (eV) Bandgap 5P-VA STK38 9.51 1.91 0.76 1.89 0.154, 0196 466 -5.50 -2.52 2.99 5P-VTPA 7.31 1.30 0.63 3.59 0.150, 0.076 451 -5.65 -2.70 2.95 5P-DVTPA 7.87 2.10 0.93 3.34 0.148, 0.120 457 -5.60 -2.71 2.89 Device: ITO/ 2-TNATA 60 nm/ NPB 15 nm/ EML 35 nm/ TPBi 20 nm/ LiF 1 nm/ Al 200 nm. OLED devices of the three compounds as an EML were fabricated as ITO/2-TNATA 60 nm/NPB 15 nm/EML 35 nm/TPBi 20 nm/LiF 1 nm/Al 200 nm. All organic films were prepared by evaporation under high vacuum of 10-6 Torr. Figure 5 shows I-V-L characteristics of the three devices. It exhibits the current density and luminance according to the applied voltage. I-V-L curves of the three compounds showed typical diode characteristics, but 5P-VTPA and 5P-DVTPA devices had the relatively smaller operating voltage compared to that of 5P-VA. The related efficiency data were also summarized in Table 2.