Proceedings of nanoGe Fall Meeting19 (NFM19)
DOI: https://doi.org/10.29363/nanoge.nfm.2019.207
Publication date: 18th July 2019
The pioneer synthesis of nanocrystals (NCs) published in 1993 opened up new routes to prepare highly monodisperse quantum dots. This, together with the outstanding electronical, optical and surface properties observed in different kinds of such semiconductor nanocrystals, has triggered an increased scientific interest on these nanomaterials. As a result, well-defined methods to synthesize and characterize NCs have been developed, and very precise control on the synthesis allows obtaining a variety of crystal structures, shapes and sizes. Despite this, usually these advances are the result of trial-mistake approaches and this is due to the lack of knowledge in the events concurring during the formation of such nanocrystals. The key point to investigate the formation dynamics of nanocrystals lies on the possibility to in-situ characterize nucleation and growth events, which take place from the millisecond to second time window.
To this aim, we have designed and assembled a state-of-the-art continuous-flow device to perform the synthesis of CdSe NCs at very different reaction conditions. The addition of optical flow cells and X-ray transparent flow cells enables in-situ characterization by means of optical spectroscopy and SAXS/WAXS experiments (synchrotron radiation facilities). With this reactor we have studied the growth dynamics of CdSe nanocrystals. Our results show that CdSe magic sized clusters are formed always as intermediates in the formation of CdSe nanocrystals. Whether they can be observed or not in solution depends mainly on the reaction temperature, which is closely related to the monomer concentration and the nucleation rate. A series of experiments utilizing worked-up CdSe clusters demonstrates our proposed new growth mechanism, according to which, CdSe nanocrystals are formed subsequently to burst dissolution of small CdSe magic sized clusters and further growth into larger clusters and nanocrystals. This new growth mechanism suggests that the classical nucleation theory, as we know it, is no longer suitable to explain formation processes in nanocrystals.
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.