Preparations of carbon nanofiber emitters for diode type field emission display with organic luminescence thin films

Carbon nanofiber (CNF), which was massively synthesized by thermal vapor deposition, emitters were fabricated by following easy processes: screen printing (SP), spin coating (SC) and spray spreading (SS) methods. Emission current density of 23 μA/cm2 at 300 V was obtained after treatment by nitric acid to CNF paste in the SP method. Specimen prepared by the SC method with nanofibers of which length is approximately 1.5 μm showed 85.2 μA/cm2 at 350 V. The surface was sufficiently smooth and CNFs were dispersive with the density of 1.0 ⁎ 107 cm− 2. Such the surface structure is suitable for electric field being applied to CNFs uniformly. The result of the SS method insisted that the existence of the nanofibers with the length less than 1 μm on the substrate was important to obtain a high performance of emitter. In the SS method sparse CNFs were obtained, that is suitable surface structure for emission, with the decanted suspension from tetrahydrofuran (THF) rather than that of dimethylformamide (DMF). The boiling temperature of solution for suspension and substrate temperature during spray were significant parameters in the SS method. The electric field enhancement factor was 2560 in the specimen with DMF.