印章结构对微接触印刷制备导电网格的影响

为了在PET基底上制备精细的透明网格状导电图案, 本工作利用微接触印刷高精度的优势, 分别采用线条结构和网格结构的印章转印银纳米粒子导电油墨, 分析了其转印过程, 并讨论了印章结构对网格图案性能的影响。结果表明: 采用线条结构的印章可真实还原印章设计尺寸, 避免了线条的扩展, 有利于提高网格图案的透光率; 同时, 在交叉处墨层较厚可提高导电性。而采用网格结构印章可一次转移快速获得网格图案, 但由于印章网格上相邻线条之间液桥的形成会使图案线宽增加, 降低其透光率; 采用间距较大的印章可使液桥断裂, 得到边缘光滑的网格图案, 但间距增大导致单位面积导电路径减少, 降低其导电性。总之, 采用线条结构印章有利于获得性能较好的网格图案, 但两次转移过程相对复杂, 需用时间较长。

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.