▎ 摘　　要

NOVELTY - Composite of graphene quantum dot (gqd) and silica in the weight ratio gqd and silica of 1-5:1-2, and depend upon source of paper, is claimed. USE - The composite is useful: in biological applications including bioimaging and drug delivery; in photocatalysis and photovoltaic devices; and in photoluminescence sensors that are used for detection of metal (e.g. ferric) ion. ADVANTAGE - The composite: can be manufactured by a one step process (claimed), in a very short time i.e. less than one hour and without using any harsh chemical, hence economical and biocompatible; exhibits bright photoluminescence and low cytotoxicity, hence suitable for biological applications; and facilitates the fabrication of different sensors with either signal-off or signal-on processes. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for one step process for the synthesis of the composite, comprising: (a) burning the paper to afford ash; (b) suspending the ash of step (a) in water by sonicating and adding oxidizing agent followed by heating in a microwave for 2-4 minutes and repeating the microwave heating for 6-7 times at 750 watts to give a black residue of gqds silica composite, with green fluorescence.