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Optical Characterization of Cesium Lead Bromide Perovskites

Optical Characterization of Cesium Lead Bromide Perovskites

Authors :
Francesco Vitale
Fabio De Matteis
Simone Privitera
Roberto Pizzoferrato
Barbara Paci
Jacopo Stefano Pelli Cresi
Amanda Generosi
Erica Ciotta
Paolo Prosposito
Faustino Martelli
Lorenzo Di Mario
Source :
Crystals, Vol 9, Iss 6, p 280 (2019), Crystals (Basel) 9 (2019). doi:10.3390/cryst9060280, info:cnr-pdr/source/autori:Fabio De Matteis, Francesco Vitale, Simone Privitera, Erica Ciotta, Roberto Pizzoferrato, Amanda Generosi, Barbara Paci, Lorenzo Di Mario, Jacopo Stefano Pelli Cresi, Faustino Martelli and Paolo Prosposito/titolo:Optical Characterization of Cesium Lead Bromide Perovskites/doi:10.3390%2Fcryst9060280/rivista:Crystals (Basel)/anno:2019/pagina_da:/pagina_a:/intervallo_pagine:/volume:9, Crystals, Volume 9, Issue 6
Publication Year :
2019
Publisher :
MDPI AG, 2019.

Abstract

CsPbBr3 and Cs4PbBr6 perovskite powders have been synthesized through a relatively simple low-temperature and low-cost method. Nanocrystalline films have also been deposited from solutions with four different molar compositions of binary salt precursors. Optical absorption, emission and excitation spectra have been performed in the UV-visible spectral range while X-ray diffraction (XRD) has been recorded to characterize the nanocrystal morphology for the different molar compositions. A preferential orientation of crystallites along the (024) crystalline plane has been observed as a function of the different deposition conditions in films growth. All the crystals show an absorption edge around 530 nm<br />Tauc plots of the absorption returned bandgaps ranging from 2.29 to 2.35 eV characteristic of CsPbBr3 phase. We attribute the UV absorption band peaked at 324 nm to the fundamental band-to-band transition for Cs4PbBr6. It was observed that the samples with the most ordered Cs4PbBr6 crystals exhibited the most intense emission of light, with a bright green emission at 520 nm, which are however due to the luminescence of the inclusion of CsPbBr3 nanoclusters into the Cs4PbBr6. The latter shows instead an intense UV emission. Differently, the pure CsPbBr3 powder did not show any intense fluorescent emission. The excitation spectra of the green fluorescent emission in all samples closely resemble the CsPbBr3 absorption with the peculiar dip around 324 nm as expected from density of state calculations reported in the literature.

Details

ISSN :
20734352
Volume :
9
Database :
OpenAIRE
Journal :
Crystals
Accession number :
edsair.doi.dedup.....a995d53e6cfa47be9127dd90acad493b
Full Text :
https://doi.org/10.3390/cryst9060280