Synthesis and properties of new luminescent hole transporting materials of triarylamine with dehydroabietic acid methyl ester moieties

A series of triarylamines based on dehydroabietic acid methyl ester moieties (6a-h) were synthesized for possible application as hole transporting materials for organic electroluminescent devices. The target compounds were characterized by elemental analysis, FT-IR, NMR, and mass spectrometry. Their optical, electrochemical, and thermal properties were investigated using UV-vis, PL spectroscopy, cyclic voltammetry (CV), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC), respectively. CV measurements show that the compounds present suitable HOMO values (in a range of −4.63 to −5.11 eV) for hole injection, which is confirmed by theoretical calculations. All compounds were thermally stable. Organic light-emitting diode devices having 6f, 6g, and 6h as a hole transporting layer showed better performance of maximum brightness, turn-on voltage, and maximum luminous efficiency than a comparable device NPB. These compounds could be excellent candidates for applications in OLED devices.

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