Proceedings of Online school on Fundamentals of Semiconductive Quantum Dots (QDsSCHOOL)
DOI: https://doi.org/10.29363/nanoge.qdsschool.2021.017
Publication date: 30th April 2021
PbS quantum dots and nanoplatelets (NPLs) are of enormous interest in the development of optoelectronic devices. However, some important aspects of their nature remain unclear. Recent studies have revealed that colloidal PbS NPLs may depart from the rock-salt crystal structure of bulk and form an orthorhombic (Pnma) modification instead[1,2]. To gain insight into the implications of such a change over the optoelectronic properties, we have synthesized orthorhombic PbS NPLs and determined the lattice parameters by means of selected area electron diffraction measurements. We have then calculated the associated band structure using density functional theory with Perdew−Burke−Ernzerhof functional for solids and with the GW approximation, including spin−orbit interactions. An indirect band gap is found, which may explain the weak luminescence reported in experiments. We derive effective masses for conduction and valence bands and deduce that quantum confinement along the a crystallographic axis (short axis of the NPL) reinforces the indirect band gap but that along b and c axes favors a direct gap instead[3] .
Calculations for colloidal nanoplatelets of 1.8 nm thickness, carried out with k·p theory [4], show that excitonic effects are strong, with binding energies of about 150 meV.
[1] A. H. Khan, et al. Chemistry of Materials 29, 2883 (2017).
[2] Q. A. Akkerman, et al. Chemistry of Materials 31, 8145 (2019).
[3] D. F. Macias, et al. Chemistry of Materials 33, 420 (2021).
[4] F. Rajadell, et al. Physical Review B 96, 035307 (2017)
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.