High colour rendering index white organic light-emitting devices with three emitting layers
A non-doped-type pure white organic light-emitting device with high colour rendering index has been reported. The structure of the device is ITO/m-MTDATA (45nm)/NPB (8nm)/DPVBi (10nm)/DCJTB (xnm)/Alq3 (5nm)/QAD (ynm)/Alq3 (10nm)/BPhen (8nm)/Alq3 (45nm)/LiF (1nm)/Al, where m-MTDATA is 4,4?,4?-tris{N,-(3-methylphenyl)-N-phenylamin}triphenylamine, NPB is N,N?-bis-(1-naphthyl)-N,N?-diphenyl-1,1?-biph-enyl-4,4?-diamine, BPhen is 4,7-diphenyl-1,10-phenanthroline, Alq3 is tris-(8-hydroxyquinoline) aluminium, DCJTB is 4-(dicyanomethylene)-2-tert-butyl-6(1,1,7,7-tetramethyl julolidyl-9-enyl)-4H-pyran, QAD is quinacridone. Through the optimization of x and y, white emission with CIE coordinates of (0.33, 0.33) at 8V was obtained, and the colour temperature and colour rendering index were 6712K and 91 at 8V, respectively. The Commission Internationale de 1Eclairage (CIE) coordinates of the device change from (0.37, 0.36) at 4V to (0.32, 0.33) at 15V that are well in the white region. Its maximum luminance was 27360cd/m2 at 15V and maximum power efficiency was 3.16lm/W at 7V. Moreover, the current efficiency is largely insensitive to the current density.
colour rendering index white organic light-emitting devices non-doped-type multiplayer structure ultrathin layer