Dongjin Lee

Abstract As an alternative to the brittle and expensive indium tin oxide (ITO) transparent conductor, a very simple, room‐temperature nanosoldering method of Ag nanowire percolation network is developed with conducting polymer to demonstrate highly flexible and even stretchable transparent conductors. The drying conducting polymer on Ag nanowire percolation network is used as a nanosoldering material inducing strong capillary‐force‐assisted stiction of the nanowires to other nanowires or to the

Abstract A transparent conductive film incorporating silver nanowires (AgNW TCF) is fabricated through roll‐to‐roll (R2R) slot‐die coating and a subsequent calendering process and applied to a resistive touch panel. To produce a uniform AgNW film on a flexible polyethylene terephthalate substrate, the R2R slot‐die coating is optimized in terms of the solvent, concentration, and flow rate of the AgNW solution, and the length of the AgNWs synthesized using a polyol method. The coated AgNW TCF is c

One of the challenges in printed electronics is the capacity to print a high resolution electrode. However, it is difficult to gain control over fidelity of microscale line-width of printed patterns especially in roll-to-roll (R2R) gravure printing process. Here, we report a simple solution based on the wettability of ink on the substrate to prevent a widening effect of printed patterns thereby enhancing the precision. The widening effect was found to be affected by intrinsic (ink wetting behavi

Tumor spheroids are considered a valuable three dimensional (3D) tissue model to study various aspects of tumor physiology for biomedical applications such as tissue engineering and drug screening as well as basic scientific endeavors, as several cell types can efficiently form spheroids by themselves in both suspension and adherent cell cultures. However, it is more desirable to utilize a 3D scaffold with tunable properties to create more physiologically relevant tumor spheroids as well as opti

The authors report pH-dependent conductance behaviors of single-walled carbon nanotube (SWCNT) multilayer thin-film sensors. SWCNTs are functionalized with carboxylic groups, and layer-by-layer assembled alternatively with polycation, polydiallyldimethyammonium chloride on the microfabricated metal electrodes. Current-voltage (I-V) characteristics show that the conductance of SWCNT multilayer thin-film sensors decreases with increase of pH values. On the other hand, the multilayer resistors with

We present ion-sensitive conductometric glucose sensors prepared by layer-by-layer (LbL) nano self-assembly of single-walled carbon nanotube (SWNT) and enzyme glucose oxidase (GOx). The carboxylated SWNT and GOx are self-assembled alternatively with a positively charged polyelectrolyte, poly(diallyldimethylammonium chloride, PDDA). Quartz crystal microbalance (QCM) study and Fourier transform infrared (FTIR) spectroscopy demonstrate GOx is negatively charged, and it is possible to successively c