Stamp Structure on the Conductive Grid Patterns Prepared by Microcontact Printing

Conductive grid patterns with fine line were achieved on the PET substrate via microcontact printing silver nanoparticle ink for its high resolution advantage. Conductive grids were patterned and compared by using the stamps with either line-or grid-structured patterns. When using line-structured stamp, the line width of the grid pattern was nearly the same as that on the stamp and the printed line edge was also smooth. The extra thickness at the cross of the grid which was due to two sequential stamp operations, was beneficial for higher conductivity. When using the grid-structured stamp, the conductive grid was acquired by only one stamp operation. However, the line width was broader than designed on the stamp and the line edge was poorer amid to liquid bridges formed between two adjacent lines on the stamp. The situation improved for the liquid bridge was easy to rupture when the line spacing of the grid line became bigger, but the conductivity was lowered as fewer conductive paths within the unit area. Hence, it is beneficial to acquire grid patterns using line-structured stamp, but the process is complicated and it will take longer time to complete two successive transfer processes.