▎ 摘　　要

NOVELTY - Preparing a deposited graphene, comprises heating a metal substrate and carbon source in a sealed ambient environment to a temperature which produces carbon vapor from the carbon source so that the vapor comes into contact with the metal substrate, maintaining the temperature for a time sufficient to form a graphene lattice and then cooling the substrate at a controlled rate to form a deposited graphene. USE - The method is useful for preparing deposited graphene i.e. as-grown graphene film or a free-standing graphene film (claimed), which is used for electronics and as genosensor. ADVANTAGE - The method: is free from feedstock gases (claimed); utilizes low quality and cheap biomass and is carried out in single step with low temperature and less processing time thus it is cost-effective; is safe, scalable and environmental friendly; and provides deposited graphene with high quality, high optical transmittance and without defects. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for as-grown graphene film or a free-standing graphene film prepared by the method.