ARTICLE
Chemical Cleavage of Layered Carbon Nitride with Enhanced Photoluminescent Performances and Photoconduction Zhixin Zhou,† Yanfei Shen,‡ Ying Li,† Anran Liu,† Songqin Liu,† and Yuanjian Zhang*,† †
Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research, Jiangsu Optoelectronic Functional Materials and Engineering Laboratory, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China and ‡Medical School, Southeast University, Nanjing 210009, China
ABSTRACT Graphene quantum dots (GQDs) and carbon dots (C-dots) have various alluring properties and
potential applications, but they are often limited by unsatisfied optical performance such as low quantum yield, ambiguous fluorescence emission mechanism, and narrow emission wavelength. Herein, we report that bulk polymeric carbon nitride could be utilized as a layered precursor to prepare carbon nitride nanostructures such as nanorods, nanoleaves and quantum dots by chemical tailoring. As doped carbon materials, these carbon nitride nanostructures not only intrinsically emitted UV lights but also well inherited the explicit photoluminescence mechanism of the bulk pristine precursor, both of which were rarely reported for GQDs and C-dots. Especially, carbon nitride quantum dots (CNQDs) had a photoluminescence quantum yield (QY) up to 46%, among the highest QY for metal-free quantum dots so far. As examples, the CNQDs were utilized as a photoluminescence probe for rapid detection of Fe3þ with a detection limit of 1 μM in 2 min and a photoconductor in an all-solid-state device. This work would open up an avenue for doped nanocarbon in developing photoelectrical devices and sensors. KEYWORDS: carbon nitride . quantum dots . photoluminescence . sensors . photoconduction
R
ecently, a wide range of carbon nanomaterials such as carbon nanodots (C-dots) and graphene quantum dots (GQDs) have attracted numerous attention due to their unique structural, optical and electronic properties that are not accessible in other materials,1,2 thus leading to great prospective applications such as in photovoltaic devices,3 photocatalysis,4,5 bioimaging68 and sensors.911 Many approaches have been developed to fabricate C-dots/ GQDs, such as breakage of graphene oxide nanosheets by hydrothermal12 or electrochemical methods,13 bottom-up synthesis,1418 strong acid-assisted cleavage of graphite-based materials (graphite fibers,19 carbon fibers,20 CX-72 carbon black21 and coals22), chemical exfoliation,23 cage-opening of fullerene24 and electron beam lithography.1 However, most of C-dots/GQDs exhibited narrow spectra coverage (blue or green) and low photoluminescence (PL) quantum yield (
