Red, green, blue and white organic electroluminescent devices

Full-color capability is an essential feature in organic electroluminescent (OEL) devices for flat panel display. This work presents novel designs for red, green, blue and white OEL devices. Indium tin oxide (ITO) was used as a glass substrate and N,N′-bis-(1-naphthyl)-N,N′-diphenyl-1,1-biphenyl-4-4′-diamine (NPB) as a hole transport layer (HTL). Bathocuproine (BCP) was used as a hole-blocking layer (HBL), DCM2, as a red fluorescent dye, was doped into the BCP layer. Tris-(8-hydroxy-quinoline) aluminum (Alq3) was used in the electron transport layer (ETL), and aluminum (Al) was used as a cathode in OEL devices with the configuration ITO/NPB (30 nm)/BCP:DCM2 (x%, 30 nm)/Alq3 (40 nm)/Al. A green OEL device is obtained by employing this structure without a BCP:DCM2 (x %) layer; a blue OEL device is obtained by using a BCP layer without the DCM2 dopant. The red OEL device is obtained by doping 10% DCM2 in the BCP layer. The white OEL device is produced by doping 1% DCM2 in the BCP layer. The CIE x and y coordinates of the white OEL device are 0.32 and 0.32, respectively.