posted on 2024-02-05, 09:29authored bySarina Yoshida, Takane Tsuchii, Mimari Matsumoto, Kenta Morita, Tatsuo Maruyama
Gold
thin films are useful as conductive materials for electrical
devices and sensors, owing to their high conductivity and inertness.
In the present study, we propose a novel alternative to conventional
gold-coating techniques (i.e., gold-vapor deposition and gold plating)
to prepare a gold thin film on a plastic surface using a gold colloidal
solution. Gold nanoparticles (AuNPs) were immobilized on a plastic
surface with a high density of amino groups (two-dimensional assembly
of AuNPs) and subsequently grew to form a gold thin film. The growth
of the AuNPs was induced using an amino acid as the reducing agent.
The selection of the amino acid significantly influenced the growth
of the AuNPs and the morphology of the gold thin film. Microscopic
observations and absorbance measurements demonstrated the growth and
connection of the AuNPs on the surface. The thickness of the gold
thin film was limited to between 50 nm and 0.5 μm by varying
the growth conditions. The formed film was lustrous and exhibited
electrical conductivity comparable to that of a gold-vapor deposited
surface. Moreover, we successfully micropatterned the gold thin film
on the plastic substrate using the present method combined with a
microcontact printing method. The results indicate that our approach
has significant potential for use in the manufacture of electrical
devices and biosensors.