Transmission electron microscope observation of organic–inorganic hybrid thin active layers of light-emitting diodes

We performed transmission electron microscope (TEM) observation of organic–inorganic hybrid thin films fabricated by the sol–gel reaction and used as the active layers of organic light-emitting diodes. The cross-sectional TEM images show that the films consist of a triple-layer structure. To evaluate the composition of these layers, the distribution of atoms in them was measured by energy-dispersive X-ray fluorescence spectroscopy. As a result, most of the organic emissive material, poly(9,9-dioctyl-fluorene-co- N -4-butylphenyl-diphenylamine (TFB), was found to be distributed in the middle layer sandwiched by SiO and SiO 2 layers. The surface SiO layer was fabricated due to the lack of oxygen. This means that the best sol–gel condition was changed due to the TFB doping; thus, the novel best condition should be found.