| dc.description.abstract | In this thesis, the high refractive index and biaxial properties of the organic small molecule fluorescent material BSB-Cz (4,4′-bis[(N-carbazole) styryl] biphenyl) are used to match the low refractive index PVK (Poly (9) -vinylcarbazole)) An OLED element for making an anisotropic slab waveguide. We refer to the optimized PVK thickness and BSB-Cz thickness of the previous study. Here, the 100 nm PVK has better photoelectric characteristics and 270 nm BSB-Cz, which is the band with the highest optical gain coefficient. We plated different electron injection layers to analyze the differences in their photoelectric properties, EL (electroluminescence) and PL (photoluminescence) spectra. We get a combination of MoO3 and Li2CO3 than PEDOT: PSS and LiF can effectively reduce the open circuit voltage of the component, which is reduced from 35V to 25V, although the overall external quantum effect (EQE%) results almost the same, but at the same voltage (40V) The combination of MoO3 and Li2CO3 performs better in light intensity and current. We also observed the non-isotropic spectral distribution of this waveguide-type OLED through spatial spectrum measurement, and observed a slight blue-shift trend with high angle.
We further observed the equivalent refractive index inside the component and the optical field distribution of the waveguide mode by inserting PVK between the glass substrate and BSB-Cz, using the thickness of PVK (0, 50, 100, 150 and 200 nm). Observing the change of the equivalent refractive index, we found that PVK above 100 nm will reduce the effect of the glass substrate on the overall equivalent refractive index below PVK, so that the overall equivalent refractive index below PVK is raised from 1.46 to 1.67, which is closer to PVK itself. The refractive index (1.6 ~ 1.7), and found that the thickness of the PVK changes can change the light field distribution of the waveguide mode. Next, we use the component structure used in this paper to observe the light field distribution of the waveguide mode. We prepare this component (glass substrate/ITO/MoO3/PVK/BSB-Cz) and cover it with four different upper media (Air; Ag; LiF/Ag; Li2CO3/Ag), the localization factor increased from 86.05% to 90.81%. It can be observed that Li2CO3/Ag can significantly improve the photon confinement in the organic layer, which makes the luminous efficiency more optimized.
| en_US |