Screen printing of carbon nanotubes for display applications

Carbon nanotubes (CNTs) have been significantly used for the field emitters for display applications. It is necessary to investigate the process variables affecting the screen printing of carbon nanotubes for the fabrication of good-quality field emitter devices with uniformity. Screen printing techniques have some advantages such as the short processing time and lower processing cost. The carbon nanotube pastes for screen printing are normally composed of organic binders, carbon nanotubes, and some additive materials. In this study, the carbon nanotube emitters for field emission displays were investigated with different processing variables such as carbon nanotube materials, screen mask mesh, cathode shape, post-treatment. The CNT pastes were printed on Cr-coated/Ag-printed soda-lime glass substrates. As a result, the processing variables were optimized for the good screen printing. From the I-V characteristics, the turn-on field of single-walled nanotubes was lower than that of multi-walled nanotubes. The decrease in the mesh number of screen masks resulted in decreasing the turn-on field and increasing the electron emission current due to the higher density and vertical alignment of printed-CNTs. As the edge length of cathode electrode increases, the electron emission from carbon nanotube was improved.