Publication date: 28th August 2024
The direct wet-chemical synthesis of 2D lead chalcogenide nanoplatelets yields photoluminescent materials with strong excitonic contribution at room temperature. [1-4] In the spirit of the recent Nobel prize for the discovery and synthesis of quantum dots (QDs) we report herein on our studies of strongly confined wet-chemically synthesized flat 2D PbSe QDs. These 2D nanocrystals have lateral dimensions of e.g. 6 x 5 nm2, a thickness of 1-3 PbSe monolayers and exhibit PL in the NIR between 860 – 1510 nm with a PL quantum yield of up to 60 %. [2,3] The highly efficient PL at fiber-optics-relevant telecommunication wavelengths renders colloidal lead chalcogenide 2D semiconductors intriguing materials for future solution-processable optics. Scanning tunnelling spectroscopy (STS) of single flat PbSe QDs revealsa conduction and valence band density of states that is typical for QDs rather than a steplike function linked to 2D nanoplatelets and substantiates the strong confinement in the flat PbSe QDs. Our experimental observations are supported by theoretical calculations of the electronic band structure using the tight-binding approach.
In the second part of the talk I will focus on colloidal 2D PbS nanoplatelets (NPLs) with a thickness of 1-2 nm. [4] The PbS NPLs exhibit excitonic PL at 720 nm, directly tying to the typical PL limit of unmodified CdSe NPLs. In the first comprehensive study of the low-temperature PL from PbS NPLs we observe unique PL features in single PbS NPLs at 4 K, including narrow zero-phonon lines widths down to 0.6 meV. Time-resolved measurements identify trions as the dominant emission source with a 2.3 ns decay time. Sub-meV spectral diffusion and no immanent blinking over minutes is observed, as well as discrete jumps without memory effects. These findings advance the understanding and underpin the potential of colloidal PbS NPLs for optical and quantum technologies. [5]
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.