웨어러블 디바이스 응용을 위한 판상형 은 나노 구조체의 합성 및 성장 메커니즘 연구

Abstract

One-dimensional or two-dimensional anisotropic metal nanocrystals, such as nanowires, nanosheets, and nanobelts, have the potential to be used in wearable electronics due to their geometric morphologies. In particular, nanoplates can be stacked between particles and have a low percolation threshold via high aspect ratio, resulting in high conductivity. However, nanoplate is not thermodynamically favored, and it is difficult to synthesize large dimensions. Furthermore, the symmetrically grown nanoplates were not suitable for wearable electronics because it easily split between particles in a small deformation. Therefore, a method of synthesizing an anisotropic nanoplates with a large size has been demanded for a wearable electronics. In present work, we report the synthesis of irregular Ag nanoplate with zig-zag morphology via coordination-based chemical reduction method. In the entire synthetic process, Ag nanoplates were formed in a kinetic control approach, in which cyanuric acid played a crucial role. As a ligand, cyanuric acid reduced the reduction rate of Ag+ ions by forming a complex with Ag+ ions, resulting decreased number of Ag atoms and was involved in the anisotropic growth of Ag nanoplates as a capping agent. In the synthesis strategy, through simultaneous extinction of the complexes and growth of zig-zag Ag nanoplates, the growth during the reaction followed ostwald ripening rather than the oriented attachment of predominant growth mechanism to irregular metal nanocrystals. When zigzag Ag nanoplate applied to rubber-based strain sensor, geometric anisotropic structure induced orientation in the stretching direction, resulting a lot of crack to create a rich percolation path. Through rich percolation path, the strain sensor exhibited good stretchability (range ~27%) and highly sensitivity (Gauge factor ~2100) responding a linear change. Based on high reliability, it enabled to monitor motion including finger bending, voice and pulse with sensor.