Proceedings of MATSUS Spring 2025 Conference (MATSUSSpring25)
Publication date: 16th December 2024
Colloidal semiconductor nanocrystals, or quantum dots (QDs), are nanometer-sized crystallites with optoelectronic properties that can be tuned by their size and shape. With the continuous advancement of computational power, density functional theory (DFT) has enabled to compute the electronic structure of QDs from atomistic models. Through DFT, the band structure of these atomistic models can be visualized via “Bloch Orbital Expansion” (BOE). This involves projecting the QD orbitals onto plane waves and then backfolding them into the first Brillouin zone defined by the QD lattice. This method allows for the analysis of surface trap states – defects within the bandgap of these materials – and facilitates strategies to remove them for different QD materials.
Since the implementation of the Restriction of Hazardous Substances (RoHS), focus shifted from the toxic Cd-, Pb-, and Hg-based materials towards the III-V semiconductors. With recent advancements in the III-V field, including the colloidal synthesis of GaAs via molten salt reactions (US),1 near-unity PLQY for InP-based QDs (Belgium, Netherlands),2,3 70% PLQY for InAs-based QDs (Italy),4 and the development of new synthesis routes for InSb (France),5 worldwide research shows the need for a screening of these III-V materials. In this study, we applied the Bloch Orbital Expansion to generic quantum dot models passivated with halides for different compositions and sizes. For the same quantum dot model, the trap band width in the valence band varied with composition, e.g. 0.60 eV for InP and 0.06 eV for GaAs. The number of valence band trap states decreased significantly when the anion was changed from P to As to Sb, across all calculated sizes. A less pronounced reduction in trap states was observed when changing the cation from In to Ga. We conclude that surface states primarily originate from the unpassivated anion (-111) facets, highlighting the importance of passivating or eliminating these facets to further improve III-V quantum dot applications.
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.