Publication date: 21st July 2025
MXenes are gaining increasing attention as heterogeneous catalysts[1, 2]. For these applications, surface defects – typically present at very low densities, often at sub-nanometric populations per gram – are believed to play a key role. However, due to this extremely low density, very few experimental techniques are sensitive enough to detect and monitor these types of sites.
In this presentation, I will show that pyrene photoemission, using borylated and amino-functionalized pyrene derivatives[3], can report on subtle surface differences in Ti₃C₂ MXenes prepared by different synthetic methods.
Specifically, Ti₃C₂ obtained by etching Ti₃AlC₂ with NH₄F, which introduces –F, –OH, and –O surface terminations, interacts strongly with boronic acid–functionalized pyrene. The binding of this molecule indicates the presence of surface –OH groups with a spatial arrangement similar to vicinal diols in organic molecules.
In contrast, 1-aminopyrene reveals unique properties when tested on Ti₃C₂Br₂ prepared by molten salt etching of Ti₃AlC₂ in a eutectic LiBr/KBr mixture. In this case, the characteristic excimer emission of 1-aminopyrene disappears upon binding to the surface, and only monomer fluorescence is observed. This indicates that NH₂ groups strongly attach to specific sites on the Br-terminated MXene, which are sufficiently isolated to prevent π–π interactions between neighboring pyrene molecules (Fig. 1).
These results demonstrate the potential of photophysical probes to detect and monitor defect sites on MXene surfaces, even at sub-nanometric concentrations.
nanoGe is a prestigious brand of successful science conferences that are developed along the year in different areas of the world since 2009. Our worldwide conferences cover cutting-edge materials topics like perovskite solar cells, photovoltaics, optoelectronics, solar fuel conversion, surface science, catalysis and two-dimensional materials, among many others.
Previously nanoGe Spring Meeting (NSM) and nanoGe Fall Meeting (NFM), MATSUS is a multiple symposia conference focused on a broad set of topics of advanced materials preparation, their fundamental properties, and their applications, in fields such as renewable energy, photovoltaics, lighting, semiconductor quantum dots, 2-D materials synthesis, charge carriers dynamics, microscopy and spectroscopy semiconductors fundamentals, etc.
International Conference on Hybrid and Organic Photovoltaics
International Conference on Hybrid and Organic Photovoltaics (HOPV) is celebrated yearly in May. The main topics are the development, function and modeling of materials and devices for hybrid and organic solar cells. The field is now dominated by perovskite solar cells but also other hybrid technologies, as organic solar cells, quantum dot solar cells, and dye-sensitized solar cells and their integration into devices for photoelectrochemical solar fuel production.
Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics
The main topics of the Asia-Pacific International Conference on Perovskite, Organic Photovoltaics and Optoelectronics (IPEROP) are discussed every year in Asia-Pacific for gathering the recent advances in the fields of material preparation, modeling and fabrication of perovskite and hybrid and organic materials. Photovoltaic devices are analyzed from fundamental physics and materials properties to a broad set of applications. The conference also covers the developments of perovskite optoelectronics, including light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.
The International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics (NIPHO) is the best place to hear the latest developments in perovskite solar cells as well as on recent advances in the fields of perovskite light-emitting diodes, lasers, optical devices, nanophotonics, nonlinear optical properties, colloidal nanostructures, photophysics and light-matter coupling.