PROCESS DEVELOPMENTS Sample Clauses

PROCESS DEVELOPMENTS. Printing processes for a wide range of materials were developed. The level of maturity varies. For some materials printability was evaluated, for others further developments were made. Printability was confirmed for semiconductors synthesized at UPD as well as for the commercially available P3CPT. A special technique for patterning P3HT was developed, in which an SU8 well is printed around the channel area. When P3HT is printed inside the well, SU8 attracts it, resulting in a thin and smooth P3HT layer in the middle of the well, where the channel is. This is important because thick and non-uniform layers are believed to decrease performance and stability. Ag, Au and PEDOT electrodes were printed by inkjet. All electrode materials were also overprinted with P3HT and transistor characterizations made using DI water as electrolyte. A modulation was observed in all structures but processes were only optimized further for Au/P3HT. Characterization data for an EGOFET with printed Au electrodes (UTDAu25TE) and printed P3HT is shown in Figure 5.1. The channel length was 10 µm. Unfortunately, we could not reproduce the result because the next Au ink batch did not perform well. Though commercial, the product is seemingly not well controlled. It should be noted that the P3HT was printed without SU8 in this case, so the device can be further improved through the technique developed later. C3 1_2_4