Preparation, characterization and optical properties evaluations of bamboo charcoal

Abstract

Herein, we report a facile and scalable approach to prepare fluorescent carbon nanostructures prepared from annealing of bamboo stems in argon atmosphere (BC). The resultant nano-structured carbon possesses an optical band gap of 2.8eV when annealed at 500 ​°C (BC-500). But BC annealed at 600 ​°C (BC-600) has an optical band gap of 3.3eV. X-ray diffraction study confirmed formation of graphite nanostructure (SP2 carbon clusters) embedded in amorphous carbon matrix. The as synthesized charcoal samples show two optical centers. When excited with UV light, two photoluminescence (PL) spectra were observed (one sharp intense emission spectra in green light region and another one in yellow light region), and found to be excitation wavelength independent. Both the PL spectra were originated from extrinsic sp2 clustered band gap. The graphitic band gap energy is altered due to -CO, -COOH and –NH2 group directly linked to sp2 carbon back bone. The PL properties of the synthesized Bamboo Charcoal nanostructures establish the material as a potential candidate for excitation wavelength-independent bio-based sensors that can convert UV light to visible light for detection and/or observation.