Fluorescence Quenching of Perylene DBPI Dye by Colloidal Low-Dimensional Gold Nanoparticles.

The interaction of a perylene DBPI dye [N,N-bis(2,5-di-tert-butylphenyl)-3,4:9,10-perylenebis(dicarboximide)] with aqueous colloidal gold nanoparticles (AuNPs) was studied using steady state fluorescence quenching measurements. The Stern-Volmer quenching rate constant (Ksv) was calculated as ~2.2 × 10(8) and ~1.072 × 10(9) M(-1) in ethanol and ethylene glycol respectively. From fluorescence quenching data, the static quenching and energy transfer play a significant role in the fluorescence quenching of DBPI with AuNPs. The apparent association constant (Kapp) was calculated as ~1.4 × 10(9) (EtOH)and ~3.7 × 10(9) M(-1) (ethylene). Due to AuNPs interaction with DBPI, the average aggregated colloidal AuNPs size is increased from ~53.39 nm (before interaction) to ~94.12 nm (after interaction).