Evaluation of Electrogenerated Chemiluminescence Cells Having Titanium Dioxide Nanoparticles-Based Electron Injection Layers Annealed at Different Temperatures

We fabricated electrogenerated chemiluminescence (ECL) cells having titanium dioxide nanoparticles (TiO2 NPs) as an electron injection layer (EIL). The EIL paste, which was spin-coated on a cathode substrate, was annealed at three different temperatures of 250°C, 350°C, and 450°C. A tris(2,2'-bipyridine)ruthenium(II) solution was used as an emitter. The ECL performances were significantly increased with the increase in the annealing temperature. The 450°C-annealed cell showed the maximum luminance of 91.9 cd/m2. By evaluating the crystalline structures and the surface chemical composition of the EIL, the improved performance was found to be attributed to the removal of undesired organic components from the EIL surface.