Development of New Hole-transporting Amorphous Molecular Materials with High Glass-transition Temperatures and Their Application in Thermally Stable Organic Electroluminescent Devices

摘要

Improvement in thermal stability and durability of organic electroluminescent (EL) devices is a subject of crucial importance for their practical applications for flat display. High-performance charge-transporting and temperatures (T_gS) remain to be developed. Tris(8-quinolinolato)aluminum (Alq_3) [1] and N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD) [2] have been most widely used as an emitting material with electron-transporting property and a hole-transporting material, respectively, for the study of organic EL devices. However, TPD lacks thermal and morphological stability. Recently, N,N'-di(1-naphthyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine has recently been used as a hole-transporting material in organic EL devices [3]; however, its thermal stability is not satisfactory, either. Likewise, Alq_3 is not an ideal material for use as an emitting material [4,5].