Tham khảo tài liệu 'organic light emitting diode part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | The efficient green emitting iridium III complexes and phosphorescent organic light emitting diode characteristics 33 Fig. 8. The device structure top Electroluminescence spectra bottom of the fabricated PHOLEDs based on Ir msippy 3 and Ir ppy 3 complexes. PHOLEDs based on Luminescence Cd m2 EQE Current efficiency Cd A Ir msippy 3 77 910 18V Ir ppy 3 44 700 18V Table 3. The device efficiencies of PHOLEDs based on Ir msippy 3 and Ir ppy 3 dopants. 4. A narrow band green emitting bulky trimethylsilyl substituted Iridium III complex and PHOLED characteristics The homoleptic iridium III complex flc-tris 2- 3 -trimethylsilylphenyl -5-trimethylsilylpyridinato iridium Ir disppy 3 has been synthesized by Suzuki coupling reaction. The effect of the substitution of bulky silyl groups on the photophysical and electroluminescence properties of Ir disppy 3 based device has also been investigated Jung 34 Organic Light Emitting Diode et al. 2009 . The trimethyl functional groups provide to the molecules such higher vapour pressure higher thermal stability good solubility and steric bulk via higher volume. These properties of silyl moieties effectively hinder the aggregation and excimer formation of ppy based iridium III complex Liu et al. 2005 . Ir disppy 3 complex is highly soluble in common organic solvents and slightly soluble in hexane due to the introduction of bulky trimethylsilyl groups. This complex is very stable up to 290 C without degradation under N2 atmosphere. Differential scanning calorimetry DSC showed the glass transition temperature of 184 C. The observed Tg value of Ir disppy 3 complex is considerably higher than that of Ir ppy 3 complex. This suggests that the introduction of silyl moieties in the ppy ring leads to higher thermal stability. Fig. 9. The molecular structure top UV-Visible and photoluminescence spectra of Ir disppy 3 complex bottom in solution solid line and in film dashed line . The UV-Visible spectra of Ir disppy 3 and Ir .
