Proceedings of nanoGe Fall Meeting 2021 (NFM21)
Publication date: 23rd September 2021
Low-dimensional lead-halide perovskite nanocrystals (pNCs) have emerged in the recent years as new emitters with remarkable optoelectronic properties, all the while being easily synthesized and processed. Recent reports of optical coherence time measurements have further shown that, although new and unprocessed, pNCs readily show favourable characteristics as a quantum light source [1,2]. The emission nonetheless remains impacted by solid-state decoherent processes such as carrier-phonon scattering and interaction with the electrostatic environment.
Here, we focus on all-inorganic CsPbBr3 NCs in the weak confinement regime (L≥2aB∼7 nm) dispersed in a polystyrene matrix. They exhibit stable and bright emission at cryogenic temperatures comprised of two- or 3-peak spectra with almost linear polarisation attributed to the bright exciton states [3]. The emission arising from this bright exciton manifold shows strong photon antibunching and fast sub-100 ps decay times. We use a combination of steady-state photoluminescence (PL) and time-resolved PL to study the emission of individual CsPbBr3 NCs from liquid-helium temperature to ~100 K and gain further understanding of the mechanisms at play, namely exciton-phonon coupling and its interaction with the exciton fine structure in this material.
As previously reported [4], the temperature-dependence of the PL reveals that the emission exhibits a blueshift and a thermal broadening induced mainly by optical phonon scattering. We identify the optical phonon mode at play in the Stokes optical phonon sidebands, together with other lower-energy optical phonon modes that do not seem to play a role in the thermal broadening.
Further information is sought from the temperature dependence of the time-resolved PL. While at the lowest temperatures, the emission is fast and mono-exponential, as temperature is increased a longer decay component gains weight and shortens, to become the main decay channel at ~80 K.
This behaviour reveals that the emission results from the interplay between thermally mixed exciton fine structure states (bright and dark). which enables us to estimate the characteristic energies of the phonons involved in this process and rationalize these findings in light of the recent literature on other hybrid and all-inorganic pNCs [5, 6].
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.