Giant electron-phonon coupling and deep conduction band resonance in metal halide double perovskite

Julian A. Steele; Pascal Puech; Masoumeh Keshavarz; Ruoxi Yang; Subhasree Banerjee; Elke Debroye; Cheol Woong Kim; Haifeng Yuan; Nam Ho Heo; Johan Vanacken; Aron Walsh; Johan Hofkens; Maarten B.J. Roeffaers

doi:10.1021/acsnano.8b02936

Giant electron-phonon coupling and deep conduction band resonance in metal halide double perovskite

Julian A. Steele, Pascal Puech, Masoumeh Keshavarz, Ruoxi Yang, Subhasree Banerjee, Elke Debroye, Cheol Woong Kim, Haifeng Yuan, Nam Ho Heo, Johan Vanacken, Aron Walsh, Johan Hofkens, Maarten B.J. Roeffaers

Department of Physics

Research output: Contribution to journal › Article › peer-review

165 Scopus citations

Abstract

The room-temperature charge carrier mobility and excitation-emission properties of metal halide perovskites are governed by their electronic band structures and intrinsic lattice phonon scattering mechanisms. Establishing how charge carriers interact within this scenario will have far-reaching consequences for developing high-efficiency materials for optoelectronic applications. Herein we evaluate the charge carrier scattering properties and conduction band environment of the double perovskite Cs₂AgBiBr₆ via a combinatorial approach; single crystal X-ray diffraction, optical excitation and temperature-dependent emission spectroscopy, resonant and nonresonant Raman scattering, further supported by first-principles calculations. We identify deep conduction band energy levels and that scattering from longitudinal optical phonons-via the Fröhlich interaction-dominates electron scattering at room temperature, manifesting within the nominally nonresonant Raman spectrum as multiphonon processes up to the fourth order. A Fröhlich coupling constant nearing 230 meV is inferred from a temperature-dependent emission line width analysis and is found to be extremely large compared to popular lead halide perovskites (between 40 and 60 meV), highlighting the fundamentally different nature of the two "single" and "double" perovskite materials branches.

Original language	English
Pages (from-to)	8081-8090
Number of pages	10
Journal	ACS Nano
Volume	12
Issue number	8
DOIs	https://doi.org/10.1021/acsnano.8b02936
State	Published - 28 Aug 2018

Bibliographical note

Funding Information:
The authors acknowledge financial support from the Research Foundation-Flanders (FWO, grant nos. G.0962.13, G.0B39.15, G.0197.11, and ZW15_09 GOH6316, postdoctoral fellowships to J.A.S., H.Y., and E.D.), KU Leuven Research Fund (C14/ 15/053), the Flemish government through long term structural funding Methusalem (CASAS2, Meth/15/04), the Hercules foundation (HER/11/14), and the Belgian Federal Science Policy Office (IAP-VII/05). The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC grant agreement (grant no. 307523), ERC-Stg LIGHT to M.B.J.R. C.W.K and N.H.H. acknowledge the Pohang Light Source, Korea, for the use of their diffractometers and computing facilities.

Publisher Copyright:
© 2018 American Chemical Society.

Keywords

CsAgBiBr
Fröhlich interactions
Raman scattering
conduction band resonance
double perovskite

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10.1021/acsnano.8b02936

Cite this

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title = "Giant electron-phonon coupling and deep conduction band resonance in metal halide double perovskite",

abstract = "The room-temperature charge carrier mobility and excitation-emission properties of metal halide perovskites are governed by their electronic band structures and intrinsic lattice phonon scattering mechanisms. Establishing how charge carriers interact within this scenario will have far-reaching consequences for developing high-efficiency materials for optoelectronic applications. Herein we evaluate the charge carrier scattering properties and conduction band environment of the double perovskite Cs2AgBiBr6 via a combinatorial approach; single crystal X-ray diffraction, optical excitation and temperature-dependent emission spectroscopy, resonant and nonresonant Raman scattering, further supported by first-principles calculations. We identify deep conduction band energy levels and that scattering from longitudinal optical phonons-via the Fr{\"o}hlich interaction-dominates electron scattering at room temperature, manifesting within the nominally nonresonant Raman spectrum as multiphonon processes up to the fourth order. A Fr{\"o}hlich coupling constant nearing 230 meV is inferred from a temperature-dependent emission line width analysis and is found to be extremely large compared to popular lead halide perovskites (between 40 and 60 meV), highlighting the fundamentally different nature of the two {"}single{"} and {"}double{"} perovskite materials branches.",

keywords = "CsAgBiBr, Fr{\"o}hlich interactions, Raman scattering, conduction band resonance, double perovskite",

author = "Steele, {Julian A.} and Pascal Puech and Masoumeh Keshavarz and Ruoxi Yang and Subhasree Banerjee and Elke Debroye and Kim, {Cheol Woong} and Haifeng Yuan and Heo, {Nam Ho} and Johan Vanacken and Aron Walsh and Johan Hofkens and Roeffaers, {Maarten B.J.}",

note = "Funding Information: The authors acknowledge financial support from the Research Foundation-Flanders (FWO, grant nos. G.0962.13, G.0B39.15, G.0197.11, and ZW15_09 GOH6316, postdoctoral fellowships to J.A.S., H.Y., and E.D.), KU Leuven Research Fund (C14/ 15/053), the Flemish government through long term structural funding Methusalem (CASAS2, Meth/15/04), the Hercules foundation (HER/11/14), and the Belgian Federal Science Policy Office (IAP-VII/05). The research leading to these results has received funding from the European Research Council under the European Union{\textquoteright}s Seventh Framework Programme (FP/2007-2013)/ERC grant agreement (grant no. 307523), ERC-Stg LIGHT to M.B.J.R. C.W.K and N.H.H. acknowledge the Pohang Light Source, Korea, for the use of their diffractometers and computing facilities. Publisher Copyright: {\textcopyright} 2018 American Chemical Society.",

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AU - Steele, Julian A.

AU - Puech, Pascal

AU - Keshavarz, Masoumeh

AU - Yang, Ruoxi

AU - Banerjee, Subhasree

AU - Debroye, Elke

AU - Kim, Cheol Woong

AU - Yuan, Haifeng

AU - Heo, Nam Ho

AU - Vanacken, Johan

AU - Walsh, Aron

AU - Hofkens, Johan

AU - Roeffaers, Maarten B.J.

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PY - 2018/8/28

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N2 - The room-temperature charge carrier mobility and excitation-emission properties of metal halide perovskites are governed by their electronic band structures and intrinsic lattice phonon scattering mechanisms. Establishing how charge carriers interact within this scenario will have far-reaching consequences for developing high-efficiency materials for optoelectronic applications. Herein we evaluate the charge carrier scattering properties and conduction band environment of the double perovskite Cs2AgBiBr6 via a combinatorial approach; single crystal X-ray diffraction, optical excitation and temperature-dependent emission spectroscopy, resonant and nonresonant Raman scattering, further supported by first-principles calculations. We identify deep conduction band energy levels and that scattering from longitudinal optical phonons-via the Fröhlich interaction-dominates electron scattering at room temperature, manifesting within the nominally nonresonant Raman spectrum as multiphonon processes up to the fourth order. A Fröhlich coupling constant nearing 230 meV is inferred from a temperature-dependent emission line width analysis and is found to be extremely large compared to popular lead halide perovskites (between 40 and 60 meV), highlighting the fundamentally different nature of the two "single" and "double" perovskite materials branches.

AB - The room-temperature charge carrier mobility and excitation-emission properties of metal halide perovskites are governed by their electronic band structures and intrinsic lattice phonon scattering mechanisms. Establishing how charge carriers interact within this scenario will have far-reaching consequences for developing high-efficiency materials for optoelectronic applications. Herein we evaluate the charge carrier scattering properties and conduction band environment of the double perovskite Cs2AgBiBr6 via a combinatorial approach; single crystal X-ray diffraction, optical excitation and temperature-dependent emission spectroscopy, resonant and nonresonant Raman scattering, further supported by first-principles calculations. We identify deep conduction band energy levels and that scattering from longitudinal optical phonons-via the Fröhlich interaction-dominates electron scattering at room temperature, manifesting within the nominally nonresonant Raman spectrum as multiphonon processes up to the fourth order. A Fröhlich coupling constant nearing 230 meV is inferred from a temperature-dependent emission line width analysis and is found to be extremely large compared to popular lead halide perovskites (between 40 and 60 meV), highlighting the fundamentally different nature of the two "single" and "double" perovskite materials branches.

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Giant electron-phonon coupling and deep conduction band resonance in metal halide double perovskite

Abstract

Bibliographical note

Keywords

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