Fine Structure of Excitons and their Interactions with Phonons in Polymorphic CsPbBr3 Single Nanocrystals

Laurent Legrand^a, Julien Ramade^a, Léon Marcel Andriambariarijaona^a, Violette Steinmetz^a, Thierry Barisien^a, Frédérick Bernardot^a, Christophe Testelin^a, Emmanuel Lhuillier^a, Quentin Glorieux^b, Alberto Bramati^b, Maria Chamarro^a

^aSorbonne Universités, UPMC Univ Paris 06, UMR CNRS 7588, Institut des Nanosciences de Paris (INSP), Place Jussieu, 4, Paris, France

^bSorbonne Universités, Laboratoire Kastler Brossel, UPMC – CNRS, ENS-PSL, Research University, Collège de France, Place Jussieu, 4, Paris, France

NIPHO
Proceedings of International Conference on Perovskite Thin Film Photovoltaics, Photonics and Optoelectronics (ABXPV18PEROPTO)

Perovskite Photonics and Optoelectronics (PEROPTO18). 1st March

Rennes, France, 2018 February 27th - March 1st

Organizers: Jacky Even and Sam Stranks

Oral, Laurent Legrand, presentation 058
DOI: https://doi.org/10.29363/nanoge.abxpvperopto.2018.058
Publication date: 11th December 2017

We investigate the exciton fine structure (EFS) and exciton-phonon coupling (EPC) of individual CsPbBr₃ nanocrystals (NCs). These NCs belong to the novel class of confined inorganic metal-halide perovkites that currently arouses enthusiasm and stimulates a huge activity due to its outstanding attendant properties within several fields of optoelectronics. The NCs studied in this work are synthesized in a form of colloidal solution through a previously described method [1] and present a cubic shape, which length dispersion is very sensitive to the temperature synthesis.

Micro-photoluminescence (μ-PL) measurements at cryogenic temperature reveal an EFS composed by either two or three Lorentzian-shaped ultrasharp peaks, which directly mirrors the adopted crystalline structure [2], namely tetragonal (doublet) or orthorhombic (triplet). We show through polarization-resolved μ-PL that these peaks are orthogonally polarized. Fine analysis of the energy structure allows to determine both exchange energy terms and crystal field terms for both structure, as well as an estimation of the dark state position in the EFS.

In a second time, EPC is studied in single polymorphic NCs. For this purpose, we perform for the first time μ-PL measurements on selectively polarized lines under various temperature from 4K to 80K. The temperature-dependence of emission linewidth follows the empirical Bose-Einstein model [3], which accounts for charge-phonon coupling for both acoustic and LO (Fröhlich) phonons. We find that acoustic coupling dominates the low temperature regime (up to 30K) while in the higher temperatures, broadening is mainly ruled by the Fröhlich term.

Our results bring fundamental information for the understanding of the CsPbBr₃ excitonic response as single emitters and provide new insights into their optical properties and performances for future integration in devices such as quantum sources.

[1] L. Protesescu, S. Yakunin, M.I. Bodnarchuk et al., Nano Lett. 15, 3692 (2015)

[2] M. Fu, P. Tamarat, H. Huang et al., Nano Lett. 17, 2895 (2017)

[3] S. Rudin, T.L. Reinecke and B. Segall, Phys. Rev. B. 42, 11218 (1990)

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.

MATSUS

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.

International Conference on Perovskite Thin Film Photovoltaics Perovskite Photonics and Optoelectronics

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.