Quantization of Energy Gap of Nitrogen Doped Graphene Quantum Dots

Wan Ibtisam Wan Omar; Okei Yamaoka; Chin Fhong Soon; Mohd Khairul Ahmad; Masaru Shimomura

Authors

Wan Ibtisam Wan Omar Graduate School of Science and Technology (GSST), Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka, 432-8011, Japan
Okei Yamaoka Graduate School of Integrated Science and Technology, Department of Engineering, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka, 432-8011, Japan
Chin Fhong Soon Microelectronic and Nanotechnology-Shamsuddin Research Centre (MiNT-SRC), Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia, 86400, Parit Raja, Batu Pahat, Johor, Malaysia
Mohd Khairul Ahmad Microelectronic and Nanotechnology-Shamsuddin Research Centre (MiNT-SRC), Faculty of Electrical and Electronic Engineering, Universiti Tun Hussein Onn Malaysia, 86400, Parit Raja, Batu Pahat, Johor, Malaysia
Masaru Shimomura Graduate School of Science and Technology (GSST), Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu, Shizuoka, 432-8011, Japan

Keywords:

Graphene quantum dots, hydrothermal, band gap

Abstract

The outstanding photoluminescence (PL) properties of graphene quantum dots (GQDs) had attracted great interest in optical applications such as fluorescent imaging. In this work, a facile one-step hydrothermal method was used to synthesize nitrogen doped GQDs (N-GQDs) with a Teflon-lined autoclave heated at 180 °C for 8 hours. High crystallinity wasdiscovered in the purified N-GQDs with a lattice spacing of 0.21 nm corresponding to in-plane graphene (100 facet). From Tauc plot, the optical band gap of N-GQDs was estimated, derived from their UV-vis absorption spectrum. The as prepared N-GQDs are strongly fluorescent and highly soluble in aqueous solution. Due to the cheap material source, this synthesis provides a feasible route towards the commercial synthesis of N-GQDs. Thus, provides an effective strategy studies of electron transfer and to engineer the optical properties of GQDs.