Suchergebnisse

Altres ajuts: we also acknowledge financial support from the Czech science foundation (20-08633X), MEYS project (LTC18039). The authors also acknowledge the assistance provided by the Research Infrastructures Nano-EnviCz (Project No. LM2015073) supported by the Ministry of Education, Youth and Sports of the Czech Republic and the project Pro-NanoEnviCz (Reg. No. CZ.02.1.01/0.0/0.0/ 16_013/0001821) supported by the Ministry of Education, Youth and Sports of the Czech Republic and the European Union - European Structural and Investments Funds in the frame of Operational Programme Research Development and Education. ; In the present work, the effect of doping on electronic properties in bulk purified and filled arc-discharge single-walled carbon nanotubes samples is studied for the first time by in situ Raman spectroelectrochemical method. A major challenge to turn the potential of SWCNTs into customer applications is to reduce or eliminate their contaminants by means of purification techniques. Besides, the endohedral functionalization of SWCNTs with organic and inorganic materials (i.e. metal halides) allows the development of tailored functional hybrids. Here, we report the purification and endohedral functionalization of SWCNTs with doping affecting the SWCNTs. Steam-purified SWCNTs have been filled with selected lutetium(iii) halides, LuCl, LuBr, LuI, and sealed using high-temperature treatment, yielding closed-ended SWCNTs with the filling material confined in the inner cavity. The purified SWCNTs were studied using TGA, EDX, STEM and Raman spectroscopy. The lutetium(iii) halide-filled SWCNTs (LuX@SWCNTs) were characterized using STEM, EDX, Raman spectroscopy and in situ Raman spectroelectrochemistry. It was found that there is a charge transfer between the SWCNTs and the encapsulated LuX (X = Cl, Br, I). The obtained data testify to the acceptor doping effect of lutetium(iii) halides incorporated into the SWCNT channels, which is accompanied by the charge transfer from nanotube walls to the introduced substances.

A major challenge to turn the potential of carbon nanotubes (CNTs) into customer applications is to reduce or eliminate their toxicity. Taking into account health and safety concerns, intensified research efforts have been conducted to improve the biocompatibility of CNTs, including the development of new shortening and purification strategies. Ideally, the methods used for improving the biocompatibility of CNTs should not alter the electronic properties of CNTs. Herein, we report on the shortening of a sample containing single-walled and double-walled CNTs using steam and obtain new insights in the properties of the steam-treated CNTs. The present study shows that short CNTs (median length ca. 200 nm) can be obtained under the reported conditions. Raman analysis reveals that wider and outer nanotubes undergo more significant changes than the narrower and inner ones, especially after a prolonged steam treatment. ; The research leading to these results has received fundingfrom the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme FP7/2007–2013/under REA grant agreement n8 290023 (RADDEL). ICN2 ac-knowledgessupport from the Severo OchoaProgram(MINECO, Grant SEV-2013-0295), and M. Kalbacthe support from MSMTproject LL1301. M. Kierkowicz and E. Pach are enrolled in the PhD Program in Materials Science at UAB. ; Peer reviewed

1 Figure.-- Abstract of the work presented at "Current Trends in Electrochemistry", 41st Meeting of the Electrochemisty Group of the Spanish Royal Society of Chemistry, 1st French‐Spanish Atelier/Workshop on Electrochemistry, 6 - 9 July 2021, Paris (France). ; Photoelectrochemical techniques are accurate for the study of intrinsic electronic properties of a great variety of nanostructured semiconductor materials, such as conductive polymers, carbon nanomaterials (GO, CNTs, CDs) or metal oxide nanoparticles. It is also a highly valuable implement to assess charge and/or energy transfer phenomena between the mentioned semiconductors unveiling their role as charge acceptors/donors, blockers/transporters, sensitizers/conditioners, or even as photoelectroactive materials for themselves, thus allowing the tuning of optoelectronic properties of composite materials, for their future application in fields related to energy and environment, such as water splitting, electronics, solar cells or water remediation. This versatility makes photoelectrochemistry a key tool in the field of nanoscience and nanotechnology. ; MINECO and AEI/FEDER/UE (project ENE2016-79282-C5-1-R), European Union (H2020-MSCAITN- 2014-ETN 642742), Gobierno de Aragón (Grupo Reconocido DGA T03_17R, FEDER/UE). ; Peer reviewed

1 figure.-- Talk delivered at the HeteroNanoCarb-2019 Conference, Advances and applications in carbon related nanomaterials: From pure to doped structures including heteroatom layers, 2019, December 09th -- 13th, Centro de Ciencias de Benasque Pedro Pascual in Benasque (Aragon, Spain). ; Photoelectrochemistry is a valuable technique for the study of intrinsic electronic properties of a great variety of nanostructured semiconductor materials, such as conductive polymers or metal oxide nanoparticles. It is also a highly valuable implement to assess charge and/or energy transfer phenomena between the mentioned semiconductors and carbon nanomaterials (GO, CNTs), unveiling their role as charge acceptors/donors, blockers/transporters, sensitizers/conditioners, or even as photoelectroactive materials for themselves, thus allowing the tuning of optoelectronic properties of composite materials, for their future application in fields related to energy and environment, such as water splitting, solar cells or water remediation. This versatility makes photoelectrochemistry a key tool in the field of carbon nanoscience and nanotechnology. ; MINEICO (project ENE2016-79282-C5-1-R, AEI/FEDER, UE), European Union (H2020-MSCA-ITN-2014-ETN 642742 ), Gobierno de Aragón (Grupo Reconocido DGA T03_17R, FEDER, UE).

6 Figuras.- 1 Suplemento.- Título del pre-print: "Metallic and semiconducting carbon nanotube features observed in a hybrid titanium dioxide electrode".- This is the pre-peer reviewed version of the following article: ChemPhysChem 20: 838-847 (2019), which has been published in final form at DOI:10.1002/cphc.201900066. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. ; The transfer of nanoscale properties from single‐walled carbon nanotubes (SWCNTs) to macroscopic systems is a topic of intense research. In particular, inorganic composites of SWCNTs and metal oxide semiconductors are being investigated for applications in electronics, energy devices, photocatalysis, and electroanalysis. In this work, a commercial SWCNT material is separated into fractions containing different conformations. The liquid fractions show clear variations in their optical absorbance spectra, indicating differences in the metallic/semiconducting character and the diameter of the SWCNTs. Also, changes in the surface chemistry and the electrical resistance are evidenced in SWCNT solid films. The starting SWCNT sample and the fractions as well are used to prepare hybrid electrodes with titanium dioxide (SWCNT/TiO2). Raman spectroscopy reflects the optoelectronic properties of SWCNTs in the SWCNT/TiO2 electrodes, while the electrochemical behavior is studied by cyclic voltammetry. A selective development of charge transfer characteristics and double‐layer behavior is achieved through the suitable choice of SWCNT fractions. ; This work has been funded by the Spanish Ministry of Science and the European Regional Development Fund (ENE 2016‐79282‐C5‐1‐R), the Government of Aragon (T03‐17R), and the European Commission (H2020‐MSCA‐ITN‐2014‐ETN 642742 "Enabling Excellence"). ; Peer reviewed

Work presented at the NanoteC19 conference, International Conference on Carbon Nanosciene and Nanotechnology, 27th-30th august 2019, Zaragoza (Spain). ; Photoelectrochemistry of nanomaterials is commonly employed in fields related to energy and environmental applications, such as water splitting, solar cells or water remediation. It is a valuable technique for the direct evaluation of the performance for the desired application. In addition, it can be used for the study of intrinsic electronic properties of nanostructured of a great variety of semiconductor materials, such as conductive polymers or metal oxide nanoparticles. It is also a highly valuable implement to assess charge and/or energy transfer phenomena between the mentioned semiconductors and carbon nanomaterials (GO, CNTs), unveiling their role as charge acceptors/donors, blockers/transporters, sensitizers/conditioners, or even as electroactive materials for themselves, thus allowing the tuning of optoelectronic properties of composite materials. This versatility makes photoelectrochemistry a key tool in the field of carbon nanoscience and nanotechnology [1- 4]. ; MINECO (project ENE2016-79282-C5-1-R), European Union (H2020-MSCA-ITN-2014-ETN 642742), Gobierno de Aragón (Grupo Reconocido DGA T03_17R), and associated EU Regional Development Funds.

Resumen del trabajo presentado al ChemOnTubes, celebrado en Bruselas (Bélgica) del 3 al 7 de abril de 2016. ; This work has been funded by MINECO and European Regional Development Fund (ENE2013-48816-C5-5-R NANOSOL-MAT), CSIC (project 2015801011 Intramural), Government of Aragón and European Social Fund (DGA-ESF-T66 Grupo Consolidado) and European Commission (H2020-MSCA-ITN-2014-ETN 642742 Enabling Excellence). ; Peer reviewed

The robust adhesion of single-walled carbon nanotubes (SWCNTs) to plastic substrates is a key issue toward their use in flexible electronic devices. In this work, semitransparent SWCNT films were prepared by spray-coating on two different plastic substrates, specifically poly(ethylene terephthalate) and poly(vinylidene fluoride). The deposited SWCNT films were treated by dipping in suitable solvents separately, namely, 53% nitric acid (HNO3) and N-methyl pyrrolidone. Direct evidence of SWCNT adhesion to the substrate was obtained by a peel-off test carried out with an adhesive tape. Moreover, these treatments caused enhanced film transparency and electrical conductivity. Electron microscopy images suggested that SWCNTs were embedded in the plastic substrates, forming a thin layer of conductive composite materials. Raman spectroscopy detected a certain level of doping in the SWCNTs after the chemical treatments, which particularly affected metallic nanotubes in the case of the HNO3 treatment. The microscopic adhesion and hardness of the SWCNT films were studied through a nanoscratch test. Overall, the efficiency of selected chemical postdeposition treatments for improving the SWCNT adhesion and the robustness of the resulting SWCNT films are demonstrated on flexible substrates of different chemical compositions. ; This work has been funded by the MINECO and the European Regional Development Fund (ENE 2016-79282-C5-1-R), the Government of Aragón (T03-17R and E14-17R), and the European Commission (H2020-MSCA-ITN-2014-ETN 642742 "Enabling Excellence"). ; Peer reviewed

Hybrid film electrodes were made of nanocrystalline titanium dioxide (TiO2) and various percentages of single‐walled carbon nanotube (SWCNT) fillers up to 5.5 wt%. A complete photoelectrochemical study was performed in both alkaline and acidic conditions by using cyclic voltammetry, potentiostatic photocurrent measurements, and open‐circuit‐potential measurements under UV/Vis irradiation. Dark voltammograms show a transition from a capacitive to a resistive behavior in the TiO2 accumulation region upon increasing SWCNT percentages. In addition, the energy levels of deep electron traps change inside the TiO2 bandgap. The new peak positions correspond to the reduction potentials of SWCNTs, and their associated charge capacities increase with the SWCNT percentage. The modifications observed in dark experiments directly impact on the shape profile of cyclic voltammograms under irradiation. As a consequence, reduction potentials of SWCNTs appear near the cathodic peaks of certain water oxidation intermediates, and may be interacting with them. On the other hand, open‐circuit photopotentials reach maximum values for small SWCNTs percentages around 0.02 wt%. An increase in potentiodynamic and potentiostatic photocurrents is observed for the electrode containing 0.02 wt% SWCNTs, compared to reference TiO2 in acidic conditions. ; The authors thank the Institute for Biocomputation and Physics of Complex Systems (BIFI) for the centrifugation laboratory. This work has been funded by MINECO and European Regional Development Fund (ENE 2016-79282-C5-1-R), Government of Aragon and European Social Fund (DGA-ESF-T66 "Grupo Consolidado") and European Commission (H2020-MSCA-ITN-2014-ETN 642742 "Enabling Excellence"). ; Peer reviewed

Resumen del trabajo presentado al Nanomath, celebrado en Toulouse (Francia) del 27 al 30 de junio de 2016. ; This work has been funcled by MINECO ancl Europea.n Regional Development Funcl (ENE2013-48816-C5-5-R "NANOSOL-MAT"), CSIC (project 2015801011 "Int.ramural"), Government of Aragón and European Social Fund (DGA-ESF-T66 "Grupo Consolidado") ancl European Commission (H2020-MSCA-ITN-2014-ETN 642742 "Enabling Excellcnce"). ; Peer reviewed

6 Figuras. 3 Tablas. ; The effect of doping on the electronic properties in bulk single-walled carbon nanotube (SWCNT) samples is studied for the first time using a new in situ Raman spectroelectrochemical method, and further verified by DFT calculations and photoresponse. We use p-/n-doped SWCNTs prepared by diazonium reactions as a versatile chemical strategy to control the SWCNT behavior. The measured and calculated data testify an acceptor effect of 4-aminobenzenesulfonic acid (p-doping), and a donor effect (n-doping) in the case of benzyl alcohol. In addition, pristine and covalently functionalized SWCNTs were used for the preparation of photoactive film electrodes. The photocathodic current in the photoelectrochemical cell is consistently modulated by the doping group. These results validate the in situ Raman spectroelectrochemistry as a unique tool box for predicting the electronic properties of functionalized SWCNTs in the form of thin films and their operational functionality in thin film devices for future optoelectronic applications. ; The authors acknowledge financial support from the European Union FP7 RADDEL programme (ITN Marie Curie Actions PEOPLE-2011-290023) and the MEYS Inter Excellence Project no. LTC18039 and H2020-MSCA RISE Agreement no. 734834 (INFUSION). This work at the Instituto de Carboquímica has been funded by the MINECO and the European Regional Development Fund (ENE 2016-79282-C5-1-R), the Government of Aragon (T03-17R), and the European Commission (H2020-MSCA-ITN-2014-ETN 642742 'Enabling Excellence'). The work in Mons is supported by the European Union H2020 iSwitch programme (H2020-MSCA-ITN-2014-ETN 642196). Computational resources in Mons were provided by the Consortium des Équipements de Calcul Intensif (CÉCI) funded by the Belgian National Fund for Scientific Research (F.R.S.-FNRS) under Grant 2.5020.11. J. C. is an FNRS research director. The authors acknowledge the assistance provided by the Research Infrastructures NanoEnviCz (Project No. LM2015073) supported by the Ministry of Education, Youth and Sports of the Czech Republic and the project Pro-NanoEnviCz (Reg. no. CZ.02.1.01/0.0/0.0/16_013/0001821) supported by the Ministry of Education, Youth and Sports of the Czech Republic and the European Union – European Structural and Investments Funds in the frame of Operational Programme Research Development and Education. J. M. G.-D. is grateful to Spanish Ministry of Science, Innovation and Universities for his 'Juan de la Cierva – Incorporación' research grant. A. S. is grateful to Dr Sara Costa and Dr Johan Ek Weis for fruitful discussions and helpful comments. ; We also acknowledge institutional support from the Unit of Information Resources for Research at the "Consejo Superior de Investigaciones Científicas" (CSIC) for the article-processing charges contribution ; Peer reviewed