Researching functional nanocarbons and colloidal photonic crystals
The primary goal of our research is to develop photoactive nanomaterials, in particular nanocarbons and hierarchically-ordered metamaterials, with the tenet of green chemistry. We explore their applications in environmental monitoring and remediation, renewable energy and health care.
Key areas
Functional nanocarbons
Fluorescent nanocarbons: science and applications
In the past decade, fluorescent carbon-based nanomaterials as a new class of materials including carbon nanodots, graphene oxide, graphene quantum dots and polymer dots have attracted significant research interest. Due to their features of highly emissive, photo-stable, non-bleaching and low to non-toxicity, fluorescent nanocarbons are poised to be an alternative to semiconductor-based quantum dots with a broad range of potential applications in sensing, bioimaging, photocatalysis, optoelectronic devices and theranostics.
Carbon dots synthesis – a small loop in Circular Economy?
The C-dots represent a special arrangement of carbon atoms and surface groups that impart them with the desired properties in applications. To achieve broad applications of C-dots in industry, we need to overcome a challenge to produce them economically, yet with atomical precision; from cheap and Earth-abundant materials and at industry-relevant scale. We are particularly interested in converting biowaste into highly functional carbon dots, because it provides a solution to reduce waste, a pressing global issue, and provides elemental doping, which is intrinsic to biowastes, for performance enhancement for carbon dots.
Diverse carbon dots for water quality sensing
Fluorescent C-dots represent a perfect integration of sensors and signal transducers. Owing to their versatile carbon chemistry, C-dots can be readily functionalised to target specific analytes, either in the form of ionic species or organic molecules. The surface functional groups and their spatial arrangement are critical to the C-dots selectivity and sensitivity to those specific analytes, Fig. 1. The carbonaceous nanoparticle provides a geometric template for surface functional groups to arrange with certain 3D spacing.
We have developed and are developing a library of carbon dots for water quality monitoring sensing heavy metals (J. colloids Inter. Sci. 437, p.28, 2015), drug molecules (Analytical Methods, 7, p.6869 2015), persistent organic pollutants (RSC Adv., 5, p.41248, 2015), phosphonate (industry sponsored, unpublished), ammonia (industry sponsored), drinking water disinfection by-products (Sustainable Materials & Technologies, 2020, e00159) and pathogens (ARC ITRH18010002).
We aspire to make a contribution to the Healthy Water initiative through our water quality sensor technologies.
Carbon dots for optoelectronics
Our research team has made the first demonstration of the NIR range photoelectric energy conversion with N-doped carbon dots in solar cells (J. Mater. Chem., 2012, 103 citations) and the discovery on the quantum-confined bandgap tuning in graphene quantum dots/TiO2 composite system. (Chem. Comm., 2016, 52, 9208, cover illustration) Recently, with human-hair derived carbon dots reaching 87% quantum yield, we have demonstrated by appropriate surface engineering, carbon dots ultra- thin film can function as the emitting layer in flexible OLEDs. (Adv. Mater., 2020, 1906176).
Carbon dots for biomedicine and biological systems
In 2009, Professor Qin Li received the Curtin Innovation Award for her visionary work on carbon dots for Cancer Therapy. She published the first work to demonstrate the feasibility of bioconjugating C-dots for targeting cancer cells (J. Phys. Chem. C, 2010, vol. 114, 12062). In 2016, with collaborators at the Chinese Academy of Sciences, we have shown C-dots can be employed as an intelligent drug delivery system for localized cancer treatment using mouse models. (most accessed paper of J. Mater. Chem. B in 2016) Our research team at Griffith University demonstrated the selective toxicity of carbon dots due to surface functional groups and its potential in cancer research and therapy (Nano Res., 2018, 11, 2204).
Laser-assisted fabrication of functional nanocarbon materials
Among diverse fabrication methods of graphene, laser reduced graphene oxide (LRGO) and laser induced graphene (LIG) have attracted significant interest in recent years, owing to its suitability for industrial production, and localized treatment and patterning without the use of chemicals. Based on the LRGO and LIG, various applications have been demonstrated such as supercapacitors, sensors, field effect transistors, solar cells and optical devices. Our research focus is on the understanding of the light-matter interactions (Carbon, 2019, vol. 141, p.83), biosensor (Carbon, 2020, vol. 163, p.385) and wearable device applications (Adv. Mater. Technologies, 2021, 2001191).
Synergistic 2D/0D, 2D/1D, 2D/3D multi-functional materials for clean energy and environment
By embedding 0D, 1D nanomaterials such as C-dots and TiO2, Cu2O nanowires into 2D materials such as reduced graphene oxide, we have observed optimised fluid flow pathways (Chem Comm, 2014, vol.50, 13089), enhanced photoelectrochemical reactions (Catalysis Sci Tech, 2018, vol.8, 1704; Emergent Mater. 2019, 2, 303), and novel cost-effective methods for material functionalization (Emergent Mater. 2019, 2, 303).
Hierarchically ordered micro and nanomaterials
This direction of research has received support from ARC Discovery grants in 2005 (DP0558727) and 2016 (DP160104089) and a Marie Curie Fellowship (2006 – 2008).
Our research team discovered the superior light trapping effect of double heterostructure colloidal crystal, which is patented (US patent granted, Patent No. 10,718,902 B2, Chinese patent no. ZL 201680046559) and published in Scientific Reports (2015). Subsequently, we developed sandwich structured TiO2 inverse photonic crystal by modulating the offset between the TiO2 electronic bandgap and the blue and red edge of the photonic bandgaps, which resulted in 5-fold as high a current density in comparison to the monolithic counterpart in a photoelectrochemical cell, demonstrating the power of light trapping for improving light harvesting (J. Mater. Chem. A, 2017, 5, 12803; Cover Illustration).
Our current research on spherical photonic crystals (photonic beads) has generated new knowledge on the synergistic effect of combining microcavity with photonic effect. (Adv. Optical Materials, 2020, 8, 1901537).