Revealing the high efficiency of fluorescence quenching of rhodamine B by triangular silver nanodisks due to the inner filter effect mechanism

Performing effective fluorescence quenching based on a metal nanomaterial is essential to construct fluorescence sensors. Silver nanomaterials are well known as an excellent candidate for an absorber in fluorescence sensing systems. Herein, we investigated the fluorescence quenching of rhodamine B (RhB) in the presence of triangular silver nanodisks in which perfect overlap between the absorption of the absorber and the fluorescence of the fluorophore was observed. The fluorescence quenching mechanism of RhB was investigated under various excitation wavelengths, together with measurement of the fluorescence lifetime. The quenching efficiency of RhB was proportional to the wavelength excitation. Remarkably, the highest efficiency of fluorescence quenching of RhB was achieved (∼60%). The quenching mechanism was investigated and revealed to be mostly due to the inner filter effect (IFE) mechanism, without the contribution of energy transfer. This result shows a completely different story from most previous studies based on silver nanoparticles, where energy transfer was reported to play a significant role. Performing effective fluorescence quenching based on a metal nanomaterial is essential to construct fluorescence sensors.