Charge-Carrier Mobility and Localization in Semiconducting Cu2AgBiI6 for Photovoltaic Applications
Autor: | Henry J. Snaith, Leonardo R. V. Buizza, Adam D. Wright, Giulia Longo, Chelsea Q. Xia, Laura M. Herz, Michael B. Johnston, Harry C. Sansom, Matthew J. Rosseinsky |
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Jazyk: | angličtina |
Rok vydání: | 2021 |
Předmět: |
Photoluminescence
Materials science Letter H600 Energy Engineering and Power Technology Physics::Optics 02 engineering and technology 010402 general chemistry Polaron 01 natural sciences Condensed Matter::Materials Science Materials Chemistry Absorption (electromagnetic radiation) Renewable Energy Sustainability and the Environment business.industry Photoconductivity G900 021001 nanoscience & nanotechnology 0104 chemical sciences Fuel Technology Semiconductor Chemistry (miscellaneous) Picosecond Optoelectronics Direct and indirect band gaps Charge carrier 0210 nano-technology business |
Zdroj: | ACS ENERGY LETTERS ACS Energy Letters |
ISSN: | 2380-8195 |
Popis: | Lead-free silver–bismuth semiconductors have become increasingly popular materials for optoelectronic applications, building upon the success of lead halide perovskites. In these materials, charge-lattice couplings fundamentally determine charge transport, critically affecting device performance. In this study, we investigate the optoelectronic properties of the recently discovered lead-free semiconductor Cu2AgBiI6 using temperature-dependent photoluminescence, absorption, and optical-pump terahertz-probe spectroscopy. We report ultrafast charge-carrier localization effects, evident from sharp THz photoconductivity decays occurring within a few picoseconds after excitation and a rise in intensity with decreasing temperature of long-lived, highly Stokes-shifted photoluminescence. We conclude that charge carriers in Cu2AgBiI6 are subject to strong charge-lattice coupling. However, such small polarons still exhibit mobilities in excess of 1 cm2 V–1 s–1 at room temperature because of low energetic barriers to formation and transport. Together with a low exciton binding energy of ∼29 meV and a direct band gap near 2.1 eV, these findings highlight Cu2AgBiI6 as an attractive lead-free material for photovoltaic applications. |
Databáze: | OpenAIRE |
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