Organic electroluminescent devices with a vacuum-deposited Lewis-acid-doped hole-injecting layer

Organic electroluminescent (EL) devices with a novel hole-injecting layer using Lewis-acid-doped arylamine derivatives were investigated. The hole-injecting layer was fabricated by coevaporation of a Lewis acid, FeCl3, and an arylamine derivative, N,N'-dinaphtyl-N,N-diphenyl bendizine (alpha-NPD). Optical absorption spectra of the Lewis acid-doped layer indicated that charge transfer (CT) complexes between alpha-NPD and FeCl3 were formed. Organic EL devices having a structure of ITO/FeCl3-doped alpha-NPD (1000 Angstrom)/alpha-NPD (500 Angstrom)/tris(8-quinolinolato)aluminum (III) (Alq(3)) (700 Angstrom)/LiF (5 Angstrom)/Al exhibited low drive and high luminance of 27000 cd/m(2) at 10V.