ABSTRACT
FIGURE 53 Molecular structure of poly(/?-phenylphenylene vinylene). (From Ref. 100.)
PPPV/PVK EL device with the ratio of 1:50 possesses the highest efficiency among these ratios. The emission efficiency dependence on PPPV content for the EL de vices with different PPPV/PVK ratios (w/w) is shown in Fig. 54. The efficiency increases with increasing PPPV/PVK ratio while the ratio is below 1:50 and then decreases slightly for ratios above 1:50. The quantum efficiencies are as high as 0.16% photons per electron for the devices in which the PPPV/PVK ratio is 1:50.
