Search results for "Òxids"
showing 6 items of 6 documents
Integrated Cleanroom Process for the Vapor-Phase Deposition of Large-Area Zeolitic Imidazolate Framework Thin Films
2019
Chemistry of materials XX(XX), acs.chemmater.9b03435 (2019). doi:10.1021/acs.chemmater.9b03435
Influence of the Molecular Weight on PVA/GO Composite Membranes for Fuel Cell Applications
2020
Composite polymer electrolyte membranes were prepared with poly (vinyl alcohol) (PVA). Two different molecular weight (Mw), 67·103 and 130·103 g·mol−1 were selected, cross-linked with sulfosuccinic acid (SSA) and doped graphene oxide (GO). The effects on the membranes obtained from these polymers were characterized in order to evaluate the fuel cell performance. Electron microscopy showed a proper nanoparticle distribution in the polymer matrix. The chemical structure was evaluated by Fourier transform infrared spectroscopy. The absence of a crystalline structure and the enhancement on the thermal stability with the addition of 1% of GO was demonstrated by thermal characterization. Total tr…
ZnS Ultrathin interfacial layers for optimizing carrier management in Sb2S3-based photovoltaics
2021
Antimony chalcogenides represent a family of materials of low toxicity and relative abundance, with a high potential for future sustainable solar energy conversion technology. However, solar cells based on antimony chalcogenides present open-circuit voltage losses that limit their efficiencies. These losses are attributed to several recombination mechanisms, with interfacial recombination being considered as one of the dominant processes. In this work, we exploit atomic layer deposition (ALD) to grow a series of ultrathin ZnS interfacial layers at the TiO2/Sb2S3 interface to mitigate interfacial recombination and to increase the carrier lifetime. ALD allows for very accurate control over th…
Phosphine Oxide Derivative as a Passivating Agent to Enhance the Performance of Perovskite Solar Cells
2021
Defects of metal-halide perovskites detrimentally influence the optoelectronic properties of the thin film and, ultimately, the photovoltaic performance of perovskite solar cells (PSCs). Especially, defect-mediated nonradiative recombination that occurs at the perovskite interface significantly limits the power conversion efficiency (PCE) of PSCs. In this regard, interfacial engineering or surface treatment of perovskites has become a viable strategy for reducing the density of surface defects, thereby improving the PCE of PSCs. Here, an organic molecule, tris(5-((tetrahydro-2H-pyran-2-yl)oxy)pentyl) phosphine oxide (THPPO), is synthesized and introduced as a defect passivation agent in PSC…
Exceedingly Fast Oxygen Atom Transfer to Olefins via a Catalytically Competent Nonheme Iron Species
2016
El mateix article està publicat en alemany a l'edició alemanya d' 'Angewandte Chemie' (ISSN 0044-8249, EISSN 1521-3757), 2016, vol. 128, núm. 21, p.6418–6422. DOI http://dx.doi.org/10.1002/ange.201601396 The reaction of [Fe(CF3SO3)2(PyNMe3)] with excess peracetic acid at −40 °C leads to the accumulation of a metastable compound that exists as a pair of electromeric species, [FeIII(OOAc)(PyNMe3)]2+ and [FeV(O)(OAc)(PyNMe3)]2+, in fast equilibrium. Stopped-flow UV/Vis analysis confirmed that oxygen atom transfer (OAT) from these electromeric species to olefinic substrates is exceedingly fast, forming epoxides with stereoretention. The impact of the electronic and steric properties of the subs…
Creixement cristal·lí mitjançant la tècnica MOCVD i caracterització morfològica i estructural dels òxids de cadmi i zinc
2019
L'òxid de cadmi (CdO) i l'òxid de zinc (ZnO) han estat postulats com dos materials amb gran potencialitat en un ampli ventall d'aplicacions tecnològiques. Pel que fa a les seues propietats físiques, ambdós presenten un caràcter semiconductor de tipus “n”, sense dopatge intencionat. A més, el seu bandgap directe a 2.2 i 3.3 eV, respectivament, asseguren un bon grau de transparència òptica en la regió infraroja i visible de l'espectre electromagnètic. La projecció d'aquests compostos en camps com la plasmònica o les tecnologies basades en transicions intersubbanda fa convenient el control per a l'obtenció de capes molt primes. Malgrat això, gairebé tots els treballs publicats reporten capes p…