Study on the Preparation of Silver Nanoparticles Coated with Diamond-Like Carbon Film and their Properties

Abstract

Ag nanoparticles (NPs) have prominent local surface plasma resonance effect (LSPR), and Ag NPs exhibit sharpest and strongest bands among all metals. Diamond-like carbon (DLC) film have good biological compatibility and also have high transmissibility in the visible and near-infrared region. A new LSPR interface between Ag NPs and ultra-thin DLC film was formed by Plasma Enhanced Chemical Vapor Deposition. The morphologies and properties of the Ag NPs coated with DLC film were studied with SEM and AFM. The results indicated that the thickness of DLC film increased with the deposition time. LSPR peak became sharper after depositing for 1 or 2 min. DLC film was prior to nucleate on the surface of Ag NPs, and it has high content of sp2 bonds near the interface. The sensitivity of new LSPR interface deposited for 20s was about the half of the sensitivity of bare Ag NPs and the sensitivity significantly decreased with deposition time. This result is helpful to understand the behavior of the new LSPR interface and to improve its sensitivity.