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Steele JA, Puech P, Keshavarz M, Yang R, Banerjee S, Debroye E, Kim CW, Yuan H, Heo NH, Vanacken J, Walsh A, Hofkens J, Roeffaers MBJ. Giant Electron-Phonon Coupling and Deep Conduction Band Resonance in Metal Halide Double Perovskite. ACS NANO 2018; 12:8081-8090. [PMID: 30086242 DOI: 10.1021/acsnano.8b02936] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
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.
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Affiliation(s)
- Julian A Steele
- Centre for Surface Chemistry and Catalysis , KU Leuven , Celestijnenlaan 200F , Leuven 3001 , Belgium
| | - Pascal Puech
- CEMES/CNRS , Université de Toulouse , 29, rue Jeanne Marvig , 31055 Toulouse , France
| | - Masoumeh Keshavarz
- Department of Chemistry , KU Leuven , Celestijnenlaan 200F , Leuven 3001 , Belgium
| | - Ruoxi Yang
- Department of Materials , Imperial College London , Exhibition Road , London SW7 2AZ , United Kingdom
- Department of Chemistry , University of Bath , Claverton Down, Bath BA2 7AY , United Kingdom
| | - Subhasree Banerjee
- Department of Chemistry , KU Leuven , Celestijnenlaan 200F , Leuven 3001 , Belgium
- School of Science, Department of Chemistry , Adamas University , Barasat-Barrackpore Road , Kolkata 700126 , West Bengal , India
| | - Elke Debroye
- Department of Chemistry , KU Leuven , Celestijnenlaan 200F , Leuven 3001 , Belgium
| | - Cheol Woong Kim
- Department of Chemistry , KU Leuven , Celestijnenlaan 200F , Leuven 3001 , Belgium
| | - Haifeng Yuan
- Department of Chemistry , KU Leuven , Celestijnenlaan 200F , Leuven 3001 , Belgium
| | - Nam Ho Heo
- Department of Applied Chemistry, School of Applied Chemical Engineering, College of Engineering , Kyungpook National University , Daegu 41566 , Korea
| | - Johan Vanacken
- INPAC-Institute for Nanoscale Physics and Chemistry , KU Leuven , Celestijnenlaan 200 D , B-3001 Leuven , Belgium
| | - Aron Walsh
- Department of Materials , Imperial College London , Exhibition Road , London SW7 2AZ , United Kingdom
- Global E3 Institute and Department of Materials Science and Engineering , Yonsei University , Seoul 120-749 , Korea
| | - Johan Hofkens
- Department of Chemistry , KU Leuven , Celestijnenlaan 200F , Leuven 3001 , Belgium
| | - Maarten B J Roeffaers
- Centre for Surface Chemistry and Catalysis , KU Leuven , Celestijnenlaan 200F , Leuven 3001 , Belgium
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