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

2020 ◽  
Author(s):  
Carlota Xavier ◽  
Paulo Zagalo ◽  
Paulo Ribeiro ◽  
Maria Raposo
Keyword(s):  
Graphene Oxide ◽  
Oxide Layer ◽  
Optical Fibers ◽  
Layer By Layer

scholarly journals Tuning of Fiber Optic Surface Reflectivity through Graphene Oxide-Based Layer-by-Layer Film Coatings

Photonics ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 11
Author(s):  
Catarina S. Monteiro ◽  
Maria Raposo ◽  
Paulo A. Ribeiro ◽  
Susana O. Silva ◽  
Orlando Frazão
Keyword(s):  
Graphene Oxide ◽  
Optical Fiber ◽  
Optical Fibers ◽  
Growth Kinetics ◽  
Fiber Optic ◽  
Hollow Microsphere ◽  
Layer Growth ◽  
Layer By Layer ◽  
Film Coatings ◽  
Surface Reflectivity

The use of graphene oxide-based coatings on optical fibers are investigated, aiming to tune the reflectivity of optical fiber surfaces for use in precision sensing devices. Graphene oxide (GO) layers are successfully deposited onto optical fiber ends, either in cleaved or hollow microspheres, by mounting combined bilayers of polyethylenimine (PEI) and GO layers using the Layer-by-Layer (LbL) technique. The reflectivity of optical fibers coated with graphene oxide layers is investigated for the telecom region allowing to both monitor layer growth kinetics and cavity characterization. Tunable reflective surfaces are successfully attained in both cleaved optical fibers and hollow microsphere fiber-based sensors by simply coating them with PEI/GO layers through the LbL film technique.

scholarly journals Enhancing the Efficiency of a Forward Osmosis Membrane with a Polydopamine/Graphene Oxide Layer Prepared Via the Modified Molecular Layer-by-Layer Method

ACS Omega ◽  
2020 ◽  
Vol 5 (30) ◽  
pp. 18738-18745
Author(s):  
Chi-feng Lin ◽  
Li-han Chung ◽  
Guan-you Lin ◽  
Min-Chao Chang ◽  
Chi-Young Lee ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Oxide Layer ◽  
Molecular Layer ◽  
Forward Osmosis ◽  
Layer By Layer ◽  
Layer Method

Fabrication of layer-by-layer graphene oxide thin film on copper substrate by electrophoretic deposition

2020 ◽  
Vol 59 (12) ◽  
pp. 125001
Author(s):  
Nan Ye ◽  
Satoka Ohnishi ◽  
Mitsuhiro Okada ◽  
Kazuto Hatakeyama ◽  
Kazuhiko Seki ◽  
...  
Keyword(s):  
Thin Film ◽  
Graphene Oxide ◽  
Electrophoretic Deposition ◽  
Copper Substrate ◽  
Oxide Thin Film ◽  
Layer By Layer ◽  
Layer Graphene

scholarly journals Thermally Stimulated Desorption Optical Fiber-Based Interrogation System: An Analysis of Graphene Oxide Layers’ Stability

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 70
Author(s):  
Maria Raposo ◽  
Carlota Xavier ◽  
Catarina Monteiro ◽  
Susana Silva ◽  
Orlando Frazão ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Optical Fiber ◽  
Optical Fiber Sensor ◽  
Layer By Layer ◽  
Film Stability ◽  
A Value ◽  
Device Reliability ◽  
Sensor Devices ◽  
Lbl Films ◽  
The Stability

Thin graphene oxide (GO) film layers are being widely used as sensing layers in different types of electrical and optical sensor devices. GO layers are particularly popular because of their tuned interface reflectivity. The stability of GO layers is fundamental for sensor device reliability, particularly in complex aqueous environments such as wastewater. In this work, the stability of GO layers in layer-by-layer (LbL) films of polyethyleneimine (PEI) and GO was investigated. The results led to the following conclusions: PEI/GO films grow linearly with the number of bilayers as long as the adsorption time is kept constant; the adsorption kinetics of a GO layer follow the behavior of the adsorption of polyelectrolytes; and the interaction associated with the growth of these films is of the ionic type since the desorption activation energy has a value of 119 ± 17 kJ/mol. Therefore, it is possible to conclude that PEI/GO films are suitable for application in optical fiber sensor devices; most importantly, an optical fiber-based interrogation setup can easily be adapted to investigate in situ desorption via a thermally stimulated process. In addition, it is possible to draw inferences about film stability in solution in a fast, reliable way when compared with the traditional ones.

scholarly journals Engineering of TiO2 or ZnO—Graphene Oxide Nanoheterojunctions for Hybrid Solar Cells Devices

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 75
Author(s):  
Duarte Carreira ◽  
Paulo A. Ribeiro ◽  
Maria Raposo ◽  
Susana Sério
Keyword(s):  
Graphene Oxide ◽  
Solar Cells ◽  
Fossil Fuels ◽  
Electrical Characterization ◽  
Modern Society ◽  
Clean Energy ◽  
Zno Films ◽  
Layer By Layer ◽  
Glass Substrates ◽  
Rc Circuit

It is currently of huge importance to find alternatives to fossil fuels to produce clean energy and to ensure the energy demands of modern society. In the present work, two types of hybrid solar cell devices were developed and characterized. The photoactive layers of the hybrid heterojunctions comprise poly (allylamine chloride) (PAH) and graphene oxide (GO) and TiO2 or ZnO films, which were deposited using the layer-by-layer technique and DC-reactive magnetron sputtering, respectively, onto fluorine-doped tin oxide (FTO)-coated glass substrates. Scanning electron microscopy evidenced a homogeneous inorganic layer, the surface morphology of which was dependent on the number of organic bilayers. The electrical characterization pointed out that FTO/(PAH/GO)50/TiO2/Al, FTO/(PAH/GO)30/ZnO/Al, and FTO/(PAH/GO)50/ZnO/Al architectures were the only ones to exhibit a diode behavior, and the last one experienced a decrease in current in a low-humidity environment. The (PAH/GO)20 impedance spectroscopy study further revealed the typical impedance of a parallel RC circuit for a dry environment, whereas in a humid environment, it approached the impedance of a series of three parallel RC circuits, indicating that water and oxygen contribute to other conduction processes. Finally, the achieved devices should be encapsulated to work successfully as solar cells.

Layer by layer assembled functionalized graphene oxide-based polymer brushes for superlubricity on steel-steel tribocontact

Soft Matter ◽  
2021 ◽  
Author(s):  
Suprakash Samanta ◽  
Rashmi Ranjan Sahoo
Keyword(s):  
Graphene Oxide ◽  
Nucleophilic Addition ◽  
Polymer Brushes ◽  
Addition Reaction ◽  
Layer By Layer ◽  
Functionalized Graphene ◽  
Covalent Functionalization ◽  
Functionalized Graphene Oxide ◽  
Nucleophilic Addition Reaction ◽  
Branched Polyethylenimine

Present study demonstrates a simple and multistep approach for the preparation of covalent functionalization of chemically prepared graphene oxide (GO) by branched polyethylenimine (PEI) through nucleophilic addition reaction to prepare...

Layer-by-layer of graphene oxide-chitosan assembly on PVA membrane surface for the pervaporation separation of water-isopropanol mixtures

2021 ◽  
Vol 38 (2) ◽  
pp. 411-421
Author(s):  
Shivshankar Chaudhari ◽  
KieYong Cho ◽  
SoHyan Joo ◽  
ByeongYun An ◽  
SongEun Lee ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Membrane Surface ◽  
Layer By Layer ◽  
Pervaporation Separation
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