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Barreto ARJ, Candiotto G, Avila HJC, Carvalho RS, Dos Santos AM, Prosa M, Benvenuti E, Moschetto S, Toffanin S, Capaz RB, Muccini M, Cremona M. Improved Performance of Organic Light-Emitting Transistors Enabled by Polyurethane Gate Dielectric. ACS Appl Mater Interfaces 2023. [PMID: 37403922 DOI: 10.1021/acsami.3c04509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 07/06/2023]
Abstract
Organic light-emitting transistors (OLETs) are multifunctional optoelectronic devices that combine in a single structure the advantages of organic light-emitting diodes (OLEDs) and organic field-effect transistors (OFETs). However, low charge mobility and high threshold voltage are critical hurdles to practical OLET implementation. This work reports on the improvements obtained by using polyurethane films as a dielectric layer material in place of the standard poly(methyl methacrylate) (PMMA) in OLET devices. It was found that polyurethane drastically reduces the number of traps in the device, thereby improving electrical and optoelectronic device parameters. In addition, a model was developed to rationalize an anomalous behavior at the pinch-off voltage. Our findings represent a step forward to overcome the limiting factors of OLETs that prevent their use in commercial electronics by providing a simple route for low-bias device operation.
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Affiliation(s)
- Arthur R J Barreto
- Organic and Molecular Optoelectronics Laboratory (LOEM), Department of Physics, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro 22451-900, RJ, Brazil
| | - Graziâni Candiotto
- Institute of Physics, Federal University of Rio de Janeiro, Rio de Janeiro 21941-909, RJ, Brazil
| | - Harold J C Avila
- Department of Physics, University of Atlantic, Puerto Colombia 081008, Atlántico, Colombia
| | - Rafael S Carvalho
- Organic and Molecular Optoelectronics Laboratory (LOEM), Department of Physics, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro 22451-900, RJ, Brazil
| | - Aline Magalhães Dos Santos
- Organic and Molecular Optoelectronics Laboratory (LOEM), Department of Physics, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro 22451-900, RJ, Brazil
| | - Mario Prosa
- Institute of Nanostructured Materials (ISMN), National Research Council (CNR), via P. Gobetti 101, 40129 Bologna, Italy
| | - Emilia Benvenuti
- Institute of Nanostructured Materials (ISMN), National Research Council (CNR), via P. Gobetti 101, 40129 Bologna, Italy
| | - Salvatore Moschetto
- Institute of Nanostructured Materials (ISMN), National Research Council (CNR), via P. Gobetti 101, 40129 Bologna, Italy
| | - Stefano Toffanin
- Institute of Nanostructured Materials (ISMN), National Research Council (CNR), via P. Gobetti 101, 40129 Bologna, Italy
| | - Rodrigo B Capaz
- Institute of Physics, Federal University of Rio de Janeiro, Rio de Janeiro 21941-909, RJ, Brazil
- Brazilian Nanotechnology National Laboratory (LNNano), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-100, SP, Brazil
| | - Michele Muccini
- Institute of Nanostructured Materials (ISMN), National Research Council (CNR), via P. Gobetti 101, 40129 Bologna, Italy
| | - Marco Cremona
- Organic and Molecular Optoelectronics Laboratory (LOEM), Department of Physics, Pontifical Catholic University of Rio de Janeiro, Rio de Janeiro 22451-900, RJ, Brazil
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Zaman Q, S Costa J, R J Barreto A, F D F Araujo J, D Carlos L, N Carneiro Neto A, Cremona M, Ahmed Z, S Cruz AF, P Souza NW, Q da Costa K, Dmitriev V, Laurenzana A, Margheri F, Del Rosso T. Dielectric-Loaded Waveguides as Advanced Platforms for Diagnostics and Application of Transparent Thin Films. Langmuir 2021; 37:3248-3260. [PMID: 33683133 DOI: 10.1021/acs.langmuir.0c02862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
An alternative approach to classical surface plasmon resonance spectroscopy is dielectric-loaded waveguide (DLWG) spectroscopy, widely used in the past decades to investigate bio-interaction kinetics. Despite their wide application, a successful and clear approach to use the DLWGs for the one-step simultaneous determination of both the thickness and refractive index of organic thin films is absent in the literature. We propose here, for the first time, an experimental protocol based on the multimodal nature of DLWGs to be followed in order to evaluate the optical constants and thickness of transparent thin films with a unique measurement. The proposed method is general and can be applied to every class of transparent organic materials, with a resolution and accuracy which depend on the nature of the external medium (gaseous or liquid), the geometrical characteristics of the DLWG, and the values of both the thickness and dielectric constant of the thin film. From the experimental point of view, the method is demonstrated in a nitrogen environment with an accuracy of about 3%, for the special case of electroluminescent thin films of Eu3+β-diketonate complexes, with an average thickness of about 20 nm. The high value of the refractive index measured for the thin film with the Eu(btfa)3(t-bpete) complex was confirmed by the use of a spectroscopic model based on the Judd-Ofelt theory, in which the magnetic dipole transition 5D0 → 7F1 (Eu3+) for similar films containing Eu3+ complexes is taken as a reference. The DLWGs are finally applied to control the refractive index changes of the organic thin films under UVA irradiation, with potential applications in dosimetry and monitoring light-induced transformation in organic thin films.
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Affiliation(s)
- Quaid Zaman
- Department of Physics, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marques de São Vicente, 22451-900 Rio de Janeiro, Brazil
| | - Jefferson S Costa
- Department of Electrical Engineering, Federal University of Pará, Belém, 66075-110 Pará, Brazil
| | - Arthur R J Barreto
- Department of Physics, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marques de São Vicente, 22451-900 Rio de Janeiro, Brazil
| | - Jefferson F D F Araujo
- Department of Physics, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marques de São Vicente, 22451-900 Rio de Janeiro, Brazil
| | - Luís D Carlos
- Phantom-g, CICECO-Aveiro Institute of Materials, Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Albano N Carneiro Neto
- Phantom-g, CICECO-Aveiro Institute of Materials, Physics Department, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Marco Cremona
- Department of Physics, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marques de São Vicente, 22451-900 Rio de Janeiro, Brazil
| | - Zubair Ahmed
- Department of Physics, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marques de São Vicente, 22451-900 Rio de Janeiro, Brazil
| | - André Felipe S Cruz
- Department of Electrical Engineering, Federal University of Pará, Belém, 66075-110 Pará, Brazil
| | - Nadson Welkson P Souza
- Department of Electrical Engineering, Federal University of Pará, Belém, 66075-110 Pará, Brazil
| | - Karlo Q da Costa
- Department of Electrical Engineering, Federal University of Pará, Belém, 66075-110 Pará, Brazil
| | - Victor Dmitriev
- Department of Electrical Engineering, Federal University of Pará, Belém, 66075-110 Pará, Brazil
| | - Anna Laurenzana
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale G.B. Morgagni 50, 50134 Florence, Italy
| | - Francesca Margheri
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale G.B. Morgagni 50, 50134 Florence, Italy
| | - Tommaso Del Rosso
- Department of Physics, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marques de São Vicente, 22451-900 Rio de Janeiro, Brazil
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