loading
Papers Papers/2022 Papers Papers/2022

Research.Publish.Connect.

Affiliation

Select a Subject

CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, UNL, Campus de Caparica, 2829-516, Caparica and Portugal
Context (please use complete words only)
Field
Sort by

3 Papers

Development of Hybrid Solar Cells based on TiO2 or ZnO-Graphene Oxide Heterojunctions

Topic: Photonics for Energy and Green Photonics

Authors: D. Carreira 1 , P. A. Ribeiro 2 , M. Raposo 2 and S. Sério 2

Affiliations: 1 Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal , 2 CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal

Digital Object Identifier: 10.5220/0009380801850191

Proceedings of PHOTOPTICS 2020, ISBN: 978-989-758-401-5

Collapse Button Quick Abstract
Nowadays it is becoming increasingly necessary to find alternatives to fossil fuels in order to produce energy from renewable sources that do not have a negative impact on the environment. In this work, two types of hybrid solar cells devices were produced, in which the photoactive layer is made of poly (allylamine chloride) (PAH) and graphene oxide (GO) organic films and titanium dioxide (TiO2) or zinc oxide (ZnO) inorganic films. These films were deposited on fluoride-doped tin oxide (FTO) glass substrates, being the organic layer deposited by the layer-by-layer (LbL) technique and the inorganic layer by DC-reactive magnetron sputtering. The aluminum electrodes were deposited by thermal evaporation. The final device configuration was FTO/(PAH/GO)x/TiO2/Al and FTO/(PAH/GO)x/ZnO/Al, where x is the number of bilayers deposited. (PAH/GO)x films were characterized by ultraviolet-visible spectrophotometry, which revealed a linearity in the growth of the films with the number of bilayers. Scanning electron microscopy (SEM) showed that the morphology of the inorganic layer is homogeneous and is dependent on the number of layers of the organic layer. The SEM cross section images further revealed the desired architecture. The electrical properties were characterized by constructing current-voltage curves. The FTO/(PAH/GO)50 /TiO2/Al, FTO/(PAH/GO)30/ZnO/Al and FTO/(PAH/GO)50/ZnO/Al devices were the only ones to exhibit a diode behavior, although they did not show any reaction when exposed to light. The FTO/ (PAH/GO)50/ZnO/Al cell experienced a decrease in current when characterized in a low humidity environment, revealing that humidity is a key factor in the conduction of the organic films.

Optimization of Graphene Oxide Layer-by-Layer Films to Be Used as an Enhancer Coating of Optical Fibers Sensors

Topics: Organic and Bio-Photonics; Photonic and Optoelectronic Materials and Devices; Photodetectors, Sensors and Imaging

Authors: Carlota Xavier , Paulo A. Zagalo , Paulo A. Ribeiro and Maria Raposo

Affiliation: CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, UNL, Campus de Caparica, 2829-516, Caparica, Portugal

Digital Object Identifier: 10.5220/0009380701920195

Proceedings of PHOTOPTICS 2020, ISBN: 978-989-758-401-5

Collapse Button Quick Abstract
The stability of Graphene oxide (GO) layers obtained by the layer-by-layer (LbL) films was investigated having in view the development of tunnable surfaces for optical fibre sensors in aqueous environments. For this purpose layer-by-layer (LbL) films based polyethylenimine (PEI) and GO, were prepared and characterized. The kinetics of adsorption of PEI/GO LBL films revealed that the adsorbed amount per bilayer increases linearly with the number of bilayers as expected. Furthermore adsorbed amount per bilayer for short adsorption times tends to a constant value revealing that GO layer growth also follows the adsorption behaviour expected polyelectrolytes in which electrostatic interaction is ruling the process. Finally desorption studies carried out to infer about GO layer stability revealed that GO layers are more stable at higher solutions pHs and if the adsorption time for each layer is short. These results/conclusions allowed to infer on the possible range of applications of PEI/GO LbL films.

Analysis of Wavelength Effect on Birefringence Creation on PAH/PAZO Layer-by-Layer Films

Topics: Photonic and Optoelectronic Materials and Devices; Optical Materials and Devices

Authors: Maria Raposo , Ana Rita Monteiro Timóteo and Paulo António Ribeiro

Affiliation: CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, UNL, Campus de Caparica, 2829-516, Caparica and Portugal

Digital Object Identifier: 10.5220/0007698603250328

Proceedings of PHOTOPTICS 2019, ISBN: 978-989-758-364-3

Collapse Button Quick Abstract
The influence of wavelength of writing laser beam in the photoinduced birefringence dynamics on layer-by-layer (LBL) films of poly(allylamine hydrochloride) (PAH) and poly{1-(4-(3-carboxy-4-hydroxyphenylazo) benzenesulfonamido)-1,2-ethanediyl, sodium salt} (PAZO) was investigated. Results revealed that the increase of laser wavelength lead to a slower birefringence build up process, whereas the relaxation process stands approximately unchanged. The buildup celerity was shown to follow the film absorbance with wavelength. The imposition of excess energy density to the PAH/PAZO LBL film was also shown to induce morphological changes in the film surface,which are also wavelength dependent.
Collapse Button Related Ontology Subjects/Areas/Topics (3)
Photonic and Optoelectronic Materials and Devices

Photonics

Photonics, Optics and Laser Technology

Context (please use complete words only)
Field
Sort by

Topic(s):

Filter listed results, by

Publication date

From:
To:
Author
Locate Author in list below
Add Author(s) to filter:

- Science and Technology Publications, Lda.
RESOURCES

Proceedings

Papers

Authors

Ontology

CONTACTS

Science and Technology Publications, Lda
Avenida de S. Francisco Xavier, Lote 7 Cv. C,
2900-616 Setúbal, Portugal.

Phone: +351 265 520 185 (National fixed network call)
Fax: +351 265 520 186
Email: info@scitepress.org

EXTERNAL LINKS

PRIMORIS

INSTICC

SCITEVENTS

CROSSREF

PROCEEDINGS SUBMITTED FOR INDEXATION BY:

dblp

Ei Compendex

SCOPUS

Semantic Scholar

Google Scholar

Microsoft Academic