Fast synthesis of high-quality reduced graphene oxide at room temperature under light exposure

Abstract

An approach of presenting new reducing reagents, sodium–benzophenone (Na–B) or Na–B in the presence of the hydrazine (Na–B–H) system under light exposure could produce rGOs with/without N-doping at room temperature in both the solution phase and on a solid substrate. Benzophenone activated those solutions acting as a photosensitizer under light. It was assumed that the newly generated radical anions with electrons from Na–B under light can reduce GO to rGO sheets (rGO_Na–B1). In addition, the Na–B–H system can allow a higher degree of reduction with the doping of nitrogen atoms by the introduction of hydrazine to produce radical anions and electrons with a sodium hydrazide complex, which helps decrease the sheet resistance of the as-made rGO_Na–B–H2. The excellent properties (very low oxygen content (C/O ∼16.2), and low sheet resistance (∼130 Ω square⁻¹)) of the rGOs were confirmed by XPS, XRD, IR, Raman spectroscopy, TGA, wettability, and sheet resistance measurements. High-quality rGO films on flexible substrates could be prepared by directly immersing the GO films in these solutions for several minutes.