Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras

Method of Synthesizing Graphene Quantum Dot

Technology Category/Market

Category – Advanced materials

Applications-Semiconductors, Supercapacitors, electronics, energy storage, sensors, coatings, composites, drug delivery systems, biomedical devices

Industry – Semiconductors, Biomedical

Market The global quantum dots market size reached US$ 6.5 Billion in 2022 and expected reach US$ 25.4 Billion by 2028, exhibiting a growth rate (CAGR) of 23.4% during 2023-2028.


Problem Statement

  • Conventional methods to synthesize graphene quantum dots (GQDs) involves complex processes, the use of strong acids, organic solvents etc.
  • Further there is requirement of  post treatment to purify or modify the surface functionalization and improve the performance of the quantum dots.


Method for synthesizing pristine graphene quantum dots (GQD):

  1. Providing a catalyst loaded substrate in a reactor
  2. Maintaining the reactor (1000 to 1200°C and inert atmosphere )
  3. Passing a hydrocarbon carrier gas
  4. Precipitation of carbon and formation of GQD
  5. The said catalyst comprises a transition metal nanoparticle, a transition metal oxide, a metal alloy, or a metal hydroxide; viz. MmNi3 and the substrate is stainless steel.
  6. The carrier gas is selected from the group of methane, ethane, liquefied petroleum gas, ethylene, acetylene, hexane, benzene, and xylene, thereby causing the atoms from the carrier gas on the catalyst surface to form the GQD.

Method for synthesizing heteroatom doped graphene quantum dots (GQD):

  1. Providing a mixture comprising graphite oxide (GO) and a heteroatom precursor in a reactor
  2. Flushing the reactor with an inert gas
  3. Flushing the reactor with an inert gas
  4. Annealing the mixture at a temperature (200 – 500°C) in the presence of H2 gas
  5. Formation of heteroatom doped GQD.
  6. The heteroatom precursor is selected from a nitrogen precursor (N- GQD), a boron precursor (B-GQD), and a phosphorus precursor (P-GQD), and wherein the weight ratio of GO to heteroatom precursor is in the range of 1: 4 to 4: 1

For the Pristine graphene quantum dots (GQD) electrode material:

  • The primary C(002) X-ray peak at 25.3° two theta using Cu K-alpha radiation
  • Reversible specific capacity for the GQD is in a range of 400 to 500 mAh/g in a voltage range of 0.01 to 3 V for lithium anode
  • Rate capability for the GQD is 400 mAh/g at 1.5 A/g for lithium anode and 76 mAh/g at  2 A/g  for sodium anode

For the Heteroatom doped graphene quantum dots (GQD) electrode material:

  • XRD broad peak at 26.6° and 24.8° corresponding to (002) peak for N –GQD and B-GQD
  • The particle size of GQD is in range of 9 nm to 12 nm
  • The reversible specific capacity of GQD is in range of 800 to 1000 mAh/g at a current density of 0.05 A/g in a voltage range of 0.01-3 V for Li anode
  • Rate capability of GQD is in the range of 400 mAh/g at 1.5 A/g for lithium anode and 51 mAh/g at 1.5 A/g for sodium anode

Key Features/Value Proposition

Technical Perspective:

  • The present invention discloses a facile and single step process to synthesize pristine and heteroatom doped GQDs.
  • Capable of producing a pristine graphene quantum dots (GQD) electrode material with cycling efficiencies for the GQD is in the range of 75-80% at 0.05 A/g at 160 cycles for lithium anode and 40-60% at 500 cycles for sodium ion battery anode.

Industrial Perspective:

  • The purity of GQD better than 99%
  • Cost- effective, simple and large-scale method
Questions about this Technology?

Contact for Licensing

Research Lab

Prof. Ramaprabhu S

Department of Physics

Intellectual Property

  • IITM IDF Ref. 1735
  • IN445132-Granted

Technology Readiness Level


Technology Validated in Lab

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