Fluorescent carbon nanoparticles synthesized from benzene by electric plasma discharge

Abstract

Various allotropes of Carbon nanoparticles (CNP) are emerging as very important building blocks for nanotechnology and biomedical applications due to their unique electronic, optical, mechanical and thermal properties. We report synthesis of crystalline CNPs from benzene using electric plasma discharge method under controlled laboratory environment. With varied electric field, different allotropes of carbon were synthesized as observed under high resolution electron microscope and selected area electron diffraction, optical spectroscopic studies revealed distinct differences between these CNPs. Raman spectroscopy of these CNPs showed a distinct peak at 1330 cm^-1 (characteristic of defect band) and another peak at 1600 cm^-1 (graphitic band). The ratio of defect to graphitic band was found to increase with increasing voltage between Fe-electrodes. Further, the ratio was altered when CNPs were formed using graphite-electrodes. Fluorescence spectroscopic measurements showed evident blue fluorescence exhibited by CNPs formed at relatively higher voltage between two Fe-electrodes. This was attributed to the increasing Fe-content, as measured by Energy dispersive X-ray analysis (EDX) and vibrating sample magnetometer (VSM). Addition of exogenous dyes in benzene during synthesis of CNPs using electric plasma discharge led to formation of fluorescent nanotubes. These fluorescent CNPs can be functionalized to target cancer cells for both imaging and targeted photothermal therapy using near-IR laser beam.