Suchergebnisse

The manufacturing of semiconducting films using solution-based approaches is considered a low cost alternative to vacuum-based thin film deposition strategies. An additional advantage of solution processing methods is the possibility to control the layer nano/microstructure. Here, we detail the production of mesoporous CuGaS2 (CGS) and ZnS layers from spin-coating and subsequent cross-linking through chalcogen-chalcogen bonds of properly functionalized nanocrystals (NCs). We further produce NC-based porous CGS/ZnS bilayers and NC-based CGS–ZnS composite layers using the same strategy. Photoelectrochemical measurements are used to demonstrate the efficacy of porous layers, and particularly the CGS/ZnS bilayers, for improved current densities and photoresponses relative to denser films deposited from as-produced NCs. ; This work was supported by the European Regional Development Funds and the Spanish MINECO project SEHTOP (ENE2016-77798-C4-3-R). T.B. thanks the FI-AGAUR Research Fellowship Program, Generalitat de Catalunya (2015 FI_B 00744). This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 712949 (TECNIOspring PLUS) and the Government of Catalonia's Agency for Business Competitiveness(ACCIÓ). S.B. acknowledges the U.S. National Science Foundation, CHE-1361741. J.L. is a Serra Hunter Fellow and is grateful to the ICREA Academia program and grants MINECO/FEDER ENE2015-63969-R and GC 2017 SGR 128 for support.

Colloidal nanocrystals (NCs) compete with molecular catalysts in the field of homogenous catalysis, offering an easier recyclability and a number of additional functionalities. Using high throughput printing technologies, colloidal NCs can be also supported onto substrates to produce cost-effective electronic, optoelectronic, electrocatalytic and sensing devices. In these two broad areas, NCs surface chemistry and supracrystal organization are key parameters determining final performance. Here, we study the influence of the surface ligands and the NC organization on the catalytic properties of In2S3, both in colloidal form and as a supported layer. In solution, well dispersed NCs stabilized in solution by inorganic ligands show the highest photocatalytic activities. On the other hand, when NCs are supported on a substrate, their organization becomes an essential parameters determining performance, and NC-based films produced through a gelation process provided five-fold higher photocurrent densities than those obtained from dense films produced by the direct printing of NCs. ; This work was supported by the European Regional Development Funds and the Spanish MINECO project BOOSTER. TB thanks FI-AGAUR Research Fellowship Program, Generalitat de Catalunya (2015 FI_B 00744). This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 712949 (TECNIOspring PLUS) and the Government of Catalonia's Agency for Business Competitiveness (ACCIÓ).

We present a novel method to produce crystalline oxide aerogels which is based on the cross linking of preformed colloidal nanocrystals (NCs) triggered by propylene oxide (PO). Ceria and titania were used to illustrate this new approach. Ceria and titania colloidal NCs with tuned geometry and crystal facets were produced in solution from the decomposition of a suitable ACS Paragon Plus Environment salt in the presence of oleylamine (OAm). The native surface ligands were replaced by amino acids, rendering the NCs colloidally stable in polar solvents. The NC colloidal solution was then gelled by adding PO, which gradually stripped the ligands from the NC surface, triggering a slow NC aggregation. NC-based metal oxide aerogels displayed both high surface areas and excellent crystallinity associated with the crystalline nature of the constituent building blocks, even without any annealing step. Such NC-based metal oxide aerogels showed higher thermal stability compared with aerogels directly produced from ionic precursors using conventional sol-gel chemistry strategies. ; This work was supported by the European Regional Development Funds and the Spanish MINECO project SEHTOP (ENE2016-77798-C4-3-R) and TEMPTATION (MAT2016-79455-P). TB thanks FI AGAUR Research Fellowship Program, Generalitat de Catalunya (2015 FI_B00744). This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 712949 (TECNIOspring PLUS) and the Government of Catalonia's Agency for Business Competitiveness (ACCIÓ).

The photodehydrogenation of ethanol is a sustainable and potentially cost-effective strategy to produce hydrogen and acetaldehyde from renewable resources. The optimization of this process requires the use of highly active, stable and selective photocatalytic materials based on abundant elements and the proper adjustment of the reaction conditions, including temperature. In this work, CuO-TiO type-II heterojunctions with different CuO amounts are obtained by a one-pot hydrothermal method. The structural and chemical properties of the produced materials and their activity toward ethanol photodehydrogenation under UV and visible light illumination are evaluated. The CuO-TiO photocatalysts exhibit a high selectivity toward acetaldehyde production and up to tenfold higher hydrogen evolution rates compared to bare TiO . We further discern here the influence of temperature and visible light absorption on the photocatalytic performance. Our results point toward the combination of energy sources in thermo-photocatalytic reactors as an efficient strategy for solar energy conversion. ; This work was supported by the MINECO project COMBENERGY (PID2019-105490RB-C32) and MICINN/FEDER project RTI2018-093996-B-C31. J.A. and M.C.S. thank funding from GC 2017 SGR 327 and MINECO project (ENE2017-85087-C3). ICN2 thanks supporting from the Severo Ochoa Program (MINECO, No. SEV-2013-0295) and the CERCA Program/Generalitat de Catalunya. Y.Z., C.X., and X.W. acknowledge the China Scholarship Council (CSC) for scholarship support. Part of the present work has been performed in the framework of Universitat Autònoma de Barcelona Materials Science PhD program. J.L. is a Serra Hunter fellow and is grateful to GC 2017 SGR 128 and ICREA Academia program. Y.L. thank the Swiss National Science Foundation (SNF) for funding under the Ambizione Energy (No. PZENP2_166871). M.C.S. has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 754510 (PROBIST) and the Severo Ochoa programme.

Ag2S nanoparticles are near-infrared (NIR) probes providing emission in a specific spectral range (~1200 nm), and superparamagnetic iron oxide nanoparticles (SPION) are colloidal systems able to respond to an external magnetic field. A disadvantage of Ag2S NPs is the attenuated luminescent properties are reduced in aqueous media and human fluids. Concerning SPION, the main drawback is the generation of undesirable clusters that reduce particle stability. Here, we fabricate biocompatible hybrid nanosystems combining Ag2S NPs and SPION by the electrospraying technique for drug delivery purposes. These nanostructures are composed of poly(lactic-co-glycolic acid) (PLGA) as the polymeric matrix in connection with both Ag2S NPs and SPIONs. Initially, we fabricate a hybrid colloidal nanosystem composed of Ag2S NPs in connection with PLGA (PLGA@Ag2S) by three different routes, showing good photoluminescent (PL) properties with relatively high average decay times. Then, we incorporate SPIONs, obtaining a PLGA polymeric matrix containing both Ag2S NPs and SPION (PLGA@Ag2S@SPION). Interestingly, in this hybrid system, the location of Ag2S NPs and SPIONs depends on the synthesis route performed during electrospraying. After a detailed characterization, we demonstrate the encapsulation and release capabilities, obtaining the kinetic release using a model chemotherapeutic drug (maslinic acid). Finally, we perform in vitro cytotoxicity assays using drug-loaded hybrid systems against several tumor cell lines. ; This research was funded "Atracción de Talento" fellowship from the Comunidad de Madrid, grant number 2018-T1/IND-10736; the Universidad Complutense de Madrid, grant number UCM-Santander (CT63/19-CT64/19); the Junta de Andalucía (P18-HO-3882, P20_00540, A-CTS-666-UGR20-FEDER); and Instituto de Salud Carlos III (PI19/01478-FEDER). P.G. acknowledges financial support from the Spanish government (MICIU) through the Ramon y Cajal research program (RyC2019-028414-I). M.F. thanks the Comunidad Autonoma de Madrid for research ...

The performance of magnetic nanoparticles is intimately entwined with their structure, mean size and magnetic anisotropy. Besides, ensembles offer a unique way of engineering the magnetic response by modifying the strength of the dipolar interactions between particles. Here we report on an experimental and theoretical analysis of magnetic hyperthermia, a rapidly developing technique in medical research and oncology. Experimentally, we demonstrate that single-domain cubic iron oxide particles resembling bacterial magnetosomes have superior magnetic heating efficiency compared to spherical particles of similar sizes. Monte Carlo simulations at the atomic level corroborate the larger anisotropy of the cubic particles in comparison with the spherical ones, thus evidencing the beneficial role of surface anisotropy in the improved heating power. Moreover we establish a quantitative link between the particle assembling, the interactions and the heating properties. This knowledge opens new perspectives for improved hyperthermia, an alternative to conventional cancer therapies ; This work was co-financed by the Spanish MAT2009-08667, MAT2009-08165 and SAF2011-25707 projects. C.M. Boubeta and A. Cabot were supported by the Spanish Government under the 'Ramón y Cajal' Fellowship program. I. Conde-Leborán was supported by the FPI Spanish program. K. Simeonidis acknowledges "Education and Lifelong Learning" Operational Program funded by EU-European Social Fund (ESF) and GSRT. Z. Saghi and P.A. Midgley acknowledge financial support from the European Union within the Framework 6 program under a contract for an Integrated Infrastructure Initiative, Reference 026019 ESTEEM. P.A. Midgley also acknowledges financial support from the European Research Council, Reference 291522-3DIMAGE. O. Iglesias acknowledges funding from the European Union FEDER funds ("Una manera de hacer Europa") and Catalan DIUE through Project 2009SGR856 ; SI