Effect of nanoclay laponite and pH on the energy transfer between fluorescent dyes

TL;DR

This study investigates how nanoclay laponite and pH influence fluorescence energy transfer between dyes in solution and films, revealing enhanced transfer efficiency and potential pH sensing applications.

Contribution

It demonstrates the effect of laponite and pH on FRET efficiency between acriflavine and rhodamine B, including potential for pH sensing over a wide range.

Findings

Energy transfer efficiency increases with laponite presence.

Maximum efficiency of 78.17% in clay dispersion.

Energy transfer efficiency varies from 4.5% to 44.45% with pH change.

Abstract

Fluorescence resonance energy transfer (FRET) between two dyes acriflavine (Acf) and rhodamine B (RhB) were investigated in solution and Layer-by-Layer (LbL) self assembled films in presence and absence of clay mineral laponite. UV-Vis absorption and fluorescence spectroscopy studies suggest both the dyes present mainly as monomer in solution and films. Energy transfer occurred from Acf to RhB in solution and LbL films. The energy transfer efficiency increases in presence of clay laponite and the maximum efficiency were 78.17% and 32.54% in clay dispersion and in LbL films respectively. Presence of laponite particles onto LbL film was confirmed by atomic force microscopy investigations with a surface coverage of more than 75%. Energy transfer efficiency was pH sensitive and the energy transfer efficiency varies from 4.5% to 44.45% in mixed dye solution for a change in pH from 3.0 to 12.0. With proper calibration it is possible to use the present system under investigation to sense pH over a wide range of pH from 3.0 to 12.0.