Open AccessA fluorescence-electrochemical study of carbon nanodots (CNDs) in bio- and photoelectronic applications and energy gap investigation
Author(s) -
Zheng Zeng,
Wendi Zhang,
Durga M. Arvapalli,
Brian P. Bloom,
Alex T. Sheardy,
Taylor Mabe,
Yiyang Liu,
Zuowei Ji,
Harish Chevva,
David H. Waldeck,
Jianjun Wei
Publication year - 2017
Publication title -
physical chemistry chemical physics/pccp. physical chemistry chemical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.053
H-Index - 239
eISSN - 1463-9084
pISSN - 1463-9076
DOI - 10.1039/c7cp02875j
Subject(s) - photocurrent , photoluminescence , photochemistry , fluorophore , electrochemistry , materials science , fluorescence , cyclic voltammetry , chemistry , nanotechnology , optoelectronics , electrode , optics , physics
Carbon nanodots (CNDs) have attracted great attention due to their superior solubility, biocompatibility, tunable photoluminescence, and opto-electronic properties. This work describes a new fluorescence-based spectroelectrochemistry approach to simultaneously study the photoluminescence and wavelength dependent photocurrent of microwave synthesized CNDs. The fluorescence of CNDs shows selective quenching upon a reversible redox couple, ferricyanide/ferrocyanide, reaction during cyclic voltammetry. The CND modified gold slide electrode demonstrates wavelength dependent photocurrent generation during the fluorescence-electrochemical study, suggesting the potential application of CNDs in photoelectronics. UV-Vis absorption and electrochemistry are used to quantify the energy gap of the CNDs, and then to calibrate a Hückel model for CNDs' electronic energy levels. The Hückel (or tight binding) model treatment of an individual CND as a molecule combines the conjugated π states (C[double bond, length as m-dash]C) with the functional groups (C[double bond, length as m-dash]O, C-O, and COOH) associated with the surface electronic states. This experimental and theoretical investigation of CNDs provides a new perspective on the optoelectronic properties of CNDs and should aid in their development for practical use in biomedicine, chemical sensing, and photoelectric devices.