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Triolo C, De Giorgi ML, Lorusso A, Cretì A, Santangelo S, Lomascolo M, Anni M, Mazzeo M, Patané S. Light Emission Properties of Thermally Evaporated CH 3NH 3PbBr 3 Perovskite from Nano- to Macro-Scale: Role of Free and Localized Excitons. NANOMATERIALS 2022; 12:nano12020211. [PMID: 35055230 PMCID: PMC8779009 DOI: 10.3390/nano12020211] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/03/2022] [Accepted: 01/07/2022] [Indexed: 02/04/2023]
Abstract
Over the past decade, interest about metal halide perovskites has rapidly increased, as they can find wide application in optoelectronic devices. Nevertheless, although thermal evaporation is crucial for the development and engineering of such devices based on multilayer structures, the optical properties of thermally deposited perovskite layers (spontaneous and amplified spontaneous emission) have been poorly investigated. This paper is a study from a nano- to micro- and macro-scale about the role of light-emitting species (namely free carriers and excitons) and trap states in the spontaneous emission of thermally evaporated thin layers of CH3NH3PbBr3 perovskite after wet air UV light trap passivation. The map of light emission from grains, carried out by SNOM at the nanoscale and by micro-PL techniques, clearly indicates that free and localized excitons (EXs) are the dominant light-emitting species, the localized excitons being the dominant ones in the presence of crystallites. These species also have a key role in the amplified spontaneous emission (ASE) process: for higher excitation densities, the relative contribution of localized EXs basically remains constant, while a clear competition between ASE and free EXs spontaneous emission is present, which suggests that ASE is due to stimulated emission from the free EXs.
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Affiliation(s)
- Claudia Triolo
- Department of Civil, Energy, Environmental and Materials Engineering (DICEAM), Mediterranean University, 89122 Reggio Calabria, Italy;
- Correspondence: (C.T.); (M.A.)
| | - Maria Luisa De Giorgi
- Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento, 73100 Lecce, Italy; (M.L.D.G.); (A.L.); (M.M.)
| | - Antonella Lorusso
- Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento, 73100 Lecce, Italy; (M.L.D.G.); (A.L.); (M.M.)
| | - Arianna Cretì
- IMM-CNR Institute for Microelectronic and Microsystems, Via per Monteroni, 73100 Lecce, Italy; (A.C.); (M.L.)
| | - Saveria Santangelo
- Department of Civil, Energy, Environmental and Materials Engineering (DICEAM), Mediterranean University, 89122 Reggio Calabria, Italy;
| | - Mauro Lomascolo
- IMM-CNR Institute for Microelectronic and Microsystems, Via per Monteroni, 73100 Lecce, Italy; (A.C.); (M.L.)
| | - Marco Anni
- Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento, 73100 Lecce, Italy; (M.L.D.G.); (A.L.); (M.M.)
- Correspondence: (C.T.); (M.A.)
| | - Marco Mazzeo
- Dipartimento di Matematica e Fisica “Ennio De Giorgi”, Università del Salento, 73100 Lecce, Italy; (M.L.D.G.); (A.L.); (M.M.)
- CNR NANOTEC—Institute of Nanotechnology, 73100 Lecce, Italy
| | - Salvatore Patané
- Department of Mathematical and Computer Sciences, Physical Sciences and Earth Sciences, University of Messina, 98166 Messina, Italy;
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