Properties of a field emission lighting plane employing highly crystalline single-walled carbon nanotubes fabricated by simple processes

We developed a new cathode for a visible ray flat plane-emission device formed from a mixture of highly crystalline single-walled carbon nanotubes (SWNTs) dispersed into an organic In₂O₃-SnO₂ precursor solution and a non-ionic surfactant. A thin film field emission cathode having highly homogeneously dispersed SWNTs was able to be fabricated with low driving voltage, high electron emission homogeneity in the plane, and high brightness efficiency by employing a simple scratching process for the film. The turn-on field of a diode using the optimized cathode was 1.2 V/μm, with the brightness homogeneity in that plane being within 5% against the averaged brightness in the lighting plane. Favorable brightness homogeneity from the lighting device to control the content of SWNTs in the coated film was achieved by employing highly crystalline SWNTs. Furthermore, brightness efficiency and emission life-time, which are important factors when comparing luminance devices, totaled more than 70 lm/W and over 5000 h until reaching the half time against the initial field emission current density. This flat plane-emission device has the potential to provide a new approach to lighting in everyday life as it contributes to energy saving through its low power consumption.