Hiromi KAWADA, Takashi Ienaga, Tomoyuki Shiozaki, Toshiya Yasunaga, Takao Fukuoka, Akinobu Yamaguchi
Stealth nanobeacons consisting of irregular-shaped aggregates of gold colloidal nanoparticles are promising anti-counterfeiting taggants due to their surface-enhanced Raman scattering (SERS) signals and high resistance to imitation as chemical physical unclonable functions (PUFs). Inkjet printing enables flexible placement of such taggants but suffers from unstable droplet ejection caused by particle aggregation arising from their irregular and anisotropic structures.