Background:
Understanding the interaction between different organic dyes and
carbon quantum dots helps us to understand several photo physical processes like electron
transfer, energy transfer, molecular sensing, drug delivery and dye degradation processes
etc.
Objective:
The primary objective of this study is to whether the carbon quantum dots can
act as an electron donor and can participate in the different photo physical processes.
Methods:
In this work, Carbon Quantum Dots (CQDLs) are synthesized in most economical
and simple carbonization method where petals of Nelumbo nucifera L. are used as a
carbon precursor. The synthesized CQDLs were characterized by using experimental techniques
like UV−Vis absorption, FT-IR, Transmission Electron Microscopy (TEM), steadystate
and time-resolved fluorescence spectroscopy.
Results:
The spectral analysis shows that the so synthesized CQDLs are spherical in shape
and its diameter is around 4.2 nm. It shows the fluorescence emission maximum at 495 nm
with a quantum yield of 4%. In this work the interaction between Carbon Quantum Dots
(CQDLs) and an organic dye Malachite Green (MG) is studied using fluorescence spectroscopic
technique under ambient pH condition (At pH 7). The quenching mechanism of
CQDLs with MG was investigated using Stern-Volmer equation and time-resolved fluorescence
lifetime studies. The results show that the dominant process of fluorescence
quenching is attributed to Forster Resonance Energy Transfer (FRET) having a donor acceptor
distance of 53 Å where CQDLs act as a donor and MG acts as an acceptor.
Conclusion:
This work has a consequence that CQDLs can be used as a donor species for
different photo physical processes such as photovoltaic cell, dye sensitized solar cell, and
also for antioxidant activity study.
Ultrafast transient absorption spectra of photoexcited YOYO-1 molecules call for additional investigations of their fluorescence quenching mechanism
