Title
Tailoring the Emission Color of Carbon Dots through Nitrogen-Induced Changes of Their Crystalline Structure
Author
Luisa Sciortino, Alice Sciortino, Radian Popescu, Reinhard Schneider, Dagmar Gerthsen, Simonpietro Agnello, Marco Cannas, Fabrizio Messina
Year
2018
Journal
The Journal of Physical Chemistry C
Abstract
Nitrogen content in carbon dots plays a crucial role both on the structure and on the optical properties. We synthesized two distinct families of CDs which differ both in structure and in the optical emission, demonstrating how nitrogen determines the structure and the optical properties of N-carbon dots in two main cases: low content and high content of nitrogen. While the low-nitrogen-content family is characterized by blue-emitting nanoparticles with a N-doped hexagonal C-graphite crystalline core structure and a complex surface structure, the high-nitrogen-content family is composed by nanoparticles behaving as dual emitters (blue and green) with a hexagonal β-C3N4 crystalline core structure and a high amount of amide groups grafted on the surface. Our data demonstrate clearly that the nitrogen is not simply a doping agent but it can also have a decisive role on the structure of carbon dots, which directly reflects into their optical properties. The emission mechanisms of the two types of N-doped CDs are discussed and related to their different structures.
Instrument
FP-6500
Keywords
Fluorescence, Nanostructures, Chemical stability, Optical properties, Materials