Energy Transfer from Carbon Dots to Organic Dye

Organic fluorophores and inorganic material such as metal nano-clusters and fluorescent quantum dots (QDs) are reliable and quantitative nanoprobes in bio-imaging and bio-sensing. The excellent water solubility, good biocompatibility, and photostability of carbon based QDs (CBQDs) make them suitable for sensing. The sensing capability of the fluorescent probe was further enhanced by the non-covalent functionalization approach with an organic dye rhodamine 6G (R6G). The nanohybrid (O-f-CD-R6G) indicates the possibility of non-radiative resonance energy transfer (NRET). Steady-state measurements indicate that the spectral overlap between the photoluminescence (PL) spectrum of O-f-CD and the absorption spectrum of the R6G makes them suitable for excited-state energy transfer studies. For Forster resonance energy transfer (FRET), the value of the critical transfer distance (R0) obtained from the spectral overlap (22 Å) is within the permissible limit. The FRET efficiency was obtained to be 8% at R0.