WOLED-三线态激子的有效提取.pptVIP

; content ;Introduction and the recent development;*; The multiple emission layers architecture reported in the literature has been able to achieve the much desired saturated-white emission. ;Solution;Sun et al.showed that by harvesting the singlet and triplets into two different channels, the efficiency roll-off can be improved. Sun et al. harvested the singlet (using fluorescent dye) near the exciton formation region and making use of the long diffusion length of triplet, harvested the triplet excitons at a distance from the formation region (using phosphorescent dyes). ;The device reported in Ref. consists of doped and undoped regions where the excitons are harvested in the doped region.;*;Experiment;*;Fig. 1. (a) Illustration for devices with different doping (host/guest) architectures. (b) Schematic diagram of the WOLED with multilayered emission region;Fig. 1. (a) Illustration for devices with different doping (host/guest) architectures. (b) Schematic diagram of the WOLED with multilayered emission region;Fig. 2. Emission spectra for devices with a thin BCzVBi layer deposited in NPB (a) and CBP (b). Emission spectra for devices with a thin Ir(2-phq)2acac layer deposited in NPB (c) and CBP (d).;Fig. 3. The intensity of the fluorescent and phosphorescent dyes at various positions in the device.;*;Fig. 4. Emission spectra for devices with singlet excitons extracted with single and multiple BCzVBi layers. Inset shows EQE as a function of current density of the corresponding devices.;So we deposited the fluorescent BCzVBi dye in the CBP layer. The structure is NPB (50 nm)/[BCzVBi (0.5 nm)/ CBP (7 nm)]p /CBP (40–7(p + q) nm)/[CBP (7 nm)/BCzVBi (0.5 nm)]q /BCP (20 nm)/ Alq3(30 nm), where p and q are the numbers of repeating host/guest layers and varied from 1 to 3.;Fig. 5. Emission spectra for devices with p and q multiple BCzVBi layers deposited near the NPB/CBP and CBP/BCP interfaces, respectively, to harvest the singlet excito