Abstract
This thesis describes the preparation and tuning of photoelectronic properties of two classes of polycyclic aromatic hydrocarbon (PAH) and Ir-bearing isoquinoline complexes. For sake of ease of better discussion, this thesis has been divided into three chapters. Chapter1 The work presented in this chapter serves as the first demonstration that structural modification of small PAH produces a great alteration of the electronic states, giving HOMO–LUMO gaps over a wide range. In our approach, the anthracene framework was attached to four phenyl groups at the 2,3,6,7 positions, and two additional phenyl, alkynyl and diphenylamino groups at the 9, 10 positions. Such substituent modification not only effectively tunes the emission wavelength, but also enhances fluorescent quantum yields. Such PAH with diverse energy gaps should have widespread applications in materials chemistry. (Chem. Commun., 2009, 6961) Chapter2 The chapter 2 demonstrates that the 2,3,6,7,9,10-hexaphenylanthracene-based derivatives were synthesized to serve as deep-blue dopants in organic EL devices. The emissions of fluorophores, fine-tuned from 439 to 453 nm with varied substituted phenyl rings attached to the anthracene core, produced PL quantum yields of 53–74% in solution. These blue dopants in dilute solutions showed no spectral red shift with increasing solvent polarity; the emission color of dopants is thus insensitive to the polarity of the medium. The HOMO、LUMO energy levels are 5.40–5.70 eV and 2.58–2.89 eV, respectively. These blue dopants undergo thermal decomposition at temperatures greater than 300 °C. The 1bb-doped EL devices attained an EQE as much as 5.3% (4.83 cd/A) with CIEx, y (0.14, 0.10)；After optimizing the device configuration, the efficiency of 4a-doped EL devices reached 6.7% (7.52 cd/A) with CIEx, y (0.14, 0.13). (J. Mater. Chem., 2011, 21, 8122) Chapter3 We designed and synthesized a series of Ir-phenyl-isoquinolino complexes with varied substituent on isoquinoline or phenyl groups to alter the emission wavelength (607 nm ~ 637nm) and the electronic states. According to result of the emission, we revealed the effect of substituent at different position on phenyl group. Among these fluoronated complexes 1i ~ 8i, the efficiency of 6i-doped device is superior to others. It show maximum external quantum efficiencies as high as 17.63% (19.88 cd/A) at CIEx, y (0.65, 0.33).