Surface Enhanced Fluorescence of Physically Polished Nanostructured Metal Surface: The Effect of the Native Oxide Layer

The fluorescence emission of Rhodamine 6G molecules at the physically polished nanostructured copper surface with varying thickness of the native oxide layer was investigated. The quenching effect was observed when the dye molecule was directly adsorbed onto the substrate surface without the formative oxide layer. However, the fluorescence was enhanced obviously when the native oxide layer was formed at the substrate surface. The experimental observations were discussed by taking into account the formation of the native oxide layer, the non-radiative energy transfer process and the local surface plasmon resonance at rough copper surface. The study highlights the importance of the native oxide layer formed on the metal substrate in surface enhanced fluorescence.