Abstract
Metal NPs have been studied for ultrasensitive chemical/biological detection exploiting the local surface plasmon resonance [1] and as a catalytic material because of their extremely large surface/volume ratio [2]. When different metal NPs are hetero-structured, different excitation wavelength can be used to detect various chemical/biological species ultra-sensitively. When applied as catalysts, multiple chemical reactions can be catalyzed. To make a practical use of these promising applications, development of formation processes of hetero nanostructures capable of controlling composition and patterns is mandatory. In this paper we demonstrate formation of hetero nanostructures consisting of silver and gold NPs. A surface of a glass substrate is chemically patterned with micro-contact-printed self-assembled monolayer (SAM) with amino terminal groups, hi the following chemical reduction processes of gold and silver NPs in the liquid- phase, gold NPs are preferentially deposited on the SAM-patterned areas and silver NPs are formed on bare glass surfaces. We have successfully achieved patterning of silver and gold NPs. Heterogeneity of nanostructures was verified by UV-Visible spectroscopy
