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Clabel H JL, Awan IT, Lozano G, Pereira-da-Silva MA, Romano RA, Rivera VAG, Ferreira SO, Marega E. Understanding the electronic properties of BaTiO 3 and Er 3+ doped BaTiO 3 films through confocal scanning microscopy and XPS: the role of oxygen vacancies. Phys Chem Chem Phys 2020; 22:15022-15034. [PMID: 32597431 DOI: 10.1039/d0cp01010c] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Photonic and electronic properties exist inherently in ferroelectric barium titanate (BaTiO3); severe luminescence quenching also exists due to the insufficient confinement of excitons. In this sense, high optical emission can only be achieved by its chemical and structural modification. Thin BaTiO3 and Er:BaTiO3 films were grown by the spin coating method on a glass substrate at room temperature. Self-trapping of excitons in the thin BaTiO3 film and its structural modification due to the doping with Er3+ ions (Er:BaTiO3) are verified using scanning confocal fluorescence microscopy (SCFM), where self-trapping excitons never occured in its pure state. By thermal treatment and doping (BaTiO3 and Er:BaTiO3) we obtained localization of the excitons, which would further induce lattice strain around the surface defects, to accommodate the self-trapped excitons. With such a self-trapped state, the structure of BaTiO3 generates broadband emission of several overlapping bands between 1.95 and 2.65 eV at room temperature, while the structure Er:BaTiO3 showed defined emission bands at 2.24 and 2.35 eV, with very weak contributions of the emission due to the self-trapping state. The influence of the variation of the excitation wavelength using 1PE and 2PE on the emission bands of BaTiO3 and Er:BaTiO3 is also investigated. The results of enhanced emission bands suggest a clear dependence of the emission intensity on the excitation energy, where a ∼3 fold enhancement in emission has been demonstrated under Er3+ (1.55 eV) excitation, which can be attributed to effective energy transfer between the Er3+ ions. As a result, it is concluded that the developed BaTiO3 and Er:BaTiO3 can pave the way for future photonic devices.
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Affiliation(s)
- J L Clabel H
- Physics Institute of São Carlos, University of São Paulo, P.O. Box 369, 13560-970, São Carlos, SP, Brazil.
| | - Iram T Awan
- Physics Institute of São Carlos, University of São Paulo, P.O. Box 369, 13560-970, São Carlos, SP, Brazil.
| | - G Lozano
- Physics Institute of São Carlos, University of São Paulo, P.O. Box 369, 13560-970, São Carlos, SP, Brazil.
| | - M A Pereira-da-Silva
- Physics Institute of São Carlos, University of São Paulo, P.O. Box 369, 13560-970, São Carlos, SP, Brazil. and University Center Central Paulista, UNICEP, P.O. Box 13563-470, São Carlos, SP, Brazil
| | - R A Romano
- Physics Institute of São Carlos, University of São Paulo, P.O. Box 369, 13560-970, São Carlos, SP, Brazil.
| | - V A G Rivera
- Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos, UNMSM, Lima, Lima, Peru
| | - S O Ferreira
- Departament of Physics, Federal University of Viçosa, UFV, P.O. Box 36570-901, Viçosa, MG, Brazil
| | - E Marega
- Physics Institute of São Carlos, University of São Paulo, P.O. Box 369, 13560-970, São Carlos, SP, Brazil.
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Xiangzhao A, Qiang M, Xingguang S. Nanosensor for dopamine and glutathione based on the quenching and recovery of the fluorescence of silica-coated quantum dots. Mikrochim Acta 2012. [DOI: 10.1007/s00604-012-0925-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Yadav RS, Mishra P, Mishra R, Kumar M, Pandey AC. Growth mechanism and optical property of CdS nanoparticles synthesized using amino-acid histidine as chelating agent under sonochemical process. ULTRASONICS SONOCHEMISTRY 2010; 17:116-122. [PMID: 19481969 DOI: 10.1016/j.ultsonch.2009.04.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2008] [Revised: 04/24/2009] [Accepted: 04/30/2009] [Indexed: 05/27/2023]
Abstract
Using amino-acid histidine as chelating agent, CdS nanoparticles have been synthesized by sonochemical method. It is found that by varying the ultrasonic irradiation time, we can tune the band gap and particle size of CdS nanoparticles. The imidazole ring of histidine captures the Cd ions from the solution, and prevents the growth of the CdS nanoparticles. The deviation in the linear relation in between cube of radius of nanoparticles and ultrasonic irradiation time confirms the growth of CdS nanoparticles occur via two process; one is the diffusion process of the reactants as well as reaction at the surface of the crystallite. CdS nanoparticles synthesized using histidine as organic chelating agent have band edge emission at approximately 481 nm and have greater photoluminescence intensity with blue-shift to higher energy due to typical quantum confinement effect.
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Affiliation(s)
- Raghvendra S Yadav
- Nanophosphor Application Centre, Physics Department, University of Allahabad, Allahabad-211002, India.
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