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Diarylamino-substituted Tetraarylethene (TAE) as an Efficient and Robust Hole Transport Material for 11% Methyl Ammonium Lead Iodide Perovskite Solar

  • Cabau, Lydia
  • Garcia-Benito, Ines
  • Molina-Ontoria, Agustin
  • Montcada, Nuria F.
  • Martin, Nazario
  • Vidal-Ferran, Anton
  • Palomares, Emilio
<p> We report the synthesis and characterisation of tetra{4-[N,N-(4,40 - dimethoxydiphenylamino)]phenyl}ethene (TAE-1) as an efficient and robust hole transport material for its application in methyl ammonium lead iodide (MAPI) perovskite solar cells. The solar cells show light-to- energy conversion efficiencies as high as 11.0% under standard measurement conditions without the need of additional dopants.</p>
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Organic sensitizers bearing a trialkylsilyl ether group for liquid dye sensitized solar cells

  • Perez-Tejada, Raquel
  • Martínez de Baroja, Natalia
  • Franco, Santiago
  • Pelleja, Laia
  • Orduna, Jesús
  • Andreu, Raquel
  • Garín, Javier
<div> In this work we present the synthesis, optical characterization and performance of five metal-free</div> <div> sensitizers for dye-sensitized solar cells (DSSC). All dyes include, for the first time, a trialkylsilyl ether</div> <div> group in the p-conjugated bridge (a thiophene ring). The influence of different donor unities, like triarylamine</div> <div> (TPA), 4H-pyranylidene and dithiafulvene has been evaluated in DSSC with a liquid I3/I_x0001_</div> <div> electrolyte, obtaining the best results with the 4H-pyranylidene moiety. The size and the position of the</div> <div> bulky group have a great importance in the efficiency of the final devices.</div> <div> In order to explain the recombination processes and electron life-time, charge extraction (CE) and</div> <div> transient photovoltage (TPV) experiments have been carried out.</div> <div> &nbsp;</div>
Proyecto:


Sustainable conversion of carbon dioxide: the advent of organocatalysis

  • G. Fiorani
  • W. Guo
  • A. W. Kleij
<p> The conversion of carbon dioxide (CO<small><sub>2</sub></small>), an abundant renewable carbon reagent, into chemicals of academic and industrial interest is of imminent importance to create a higher degree of sustainability in chemical processing and production. Recent progress in this field is characterised by a plethora of organic molecules able to mediate the conversion of suitable substrates in the presence of CO<small><sub>2</sub></small> into a variety of value-added commodities with advantageous features combining cost-effectiveness, metal-free transformations and general substrate activation profiles. In this review, the latest developments in the field of CO<small><sub>2</sub></small> catalysis are discussed with a focus on organo-mediated conversions and their increasing importance in serving as practicable alternatives for metal-based processes. Also a critical assessment of the state-of-the-art methods is presented with attention to those features that need further development to increase the usefulness of organocatalysis in the production of organic molecules of potential commercial interest.</p>
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Ni-catalyzed Reductive Carboxylation of Cyclopropyl Motifs with CO2

  • Moragas, Toni
  • Martin, Ruben
<div> <p> A Ni-catalyzed reductive carboxylation technique en route to cyclopropyl carboxylic acids has been developed. This user-friendly and mild transformation operates at atmospheric pressure of CO <sub>2 </sub>and utilizes either organic halides or alkene precursors, thus representing the first example of catalytic reductive carboxylation of secondary counterparts lacking adjacent p-components.</p> </div> <p> &nbsp;</p>
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Continuous DMC synthesis from CO2 and methanol over CeO2 catalyst in fixed bed reactor in presence of dehydrating agent

  • Bansode, Atul
  • Urakawa, Atsushi
<p> Methanol and carbon dioxide are continuously and efficiently converted to dimethyl carbonate (DMC) over CeO<sub>2 </sub>catalyst using 2-cyanopyrindine as a recyclable dehydrating agent in a fixed bed reactor. The process was operated over a wide range of pressure (1-300 bar) by feeding CO<sub>2</sub> and the stoichiometric amount of methanol and 2-cyanopyrinde mixture into the reactor. The study shows successful demonstration of direct DMC synthesis mediated by dehydrating agent with outstanding methanol conversion (&gt;95%) and dimethyl carbonate selectivity (&gt;99%) under optimized conditions. Remarkably higher reaction rates were achieved compared to those in batch operation.</p>
Proyecto:


Thermodynamic Stability of Heterodimetallic [LnLn′] Complexes: Synthesis and DFT Studies

  • González-Fabra, Joan
  • Bandeira, Nuno
  • Velasco, Verónica
  • Barrios,Leoní A.
  • Aguilà,David
  • Teat, Simon J.
  • Roubeau, Olivier
  • Bo, Carles
  • Aromí, Gullem
<div class="page" title="Page 1"> <div class="layoutArea"> <div class="column"> <p> <span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">The solid-state and solution configurations of the heterodimetallic complexes (Hpy)[LaEr(HL)</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">3</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">(NO</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">3</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">)(py)(H</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">2</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">O)] (</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR6'">1</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">), (Hpy)[CeEr(HL)</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">3</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">(NO</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">3</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">)(py)(H</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">2</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">O)] (</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR6'">2</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">), (Hpy)[CeGd(HL)</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">3</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">(NO</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">3</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">)- (py)(H</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">2</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">O)] (</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR6'">3</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">), (Hpy)[PrSm(HL)</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">3</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">(NO</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">3</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">)(py)(H</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">2</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">O)] (</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR6'">4</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">), and (Hpy)</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">2</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">[LaYb(HL)</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">3</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">(NO</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">3</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">)(H</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">2</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">O)](NO</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">3</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">) (</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR6'">5</span><span style="font-size: 9.000000pt; font-family: 'AdvMYR4'">), in which H</span><span style="font-size: 6.000000pt; font-family: 'AdvMYR4'; vertical-align: -2.000000pt">3</span><span style="font-siz
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MoS2-based materials as alternative cathode catalyst for PEM electrolysis

  • Corrales-Sánchez, Tachmajal
  • Ampurdanés, Jordi
  • Urakawa, Atsushi
<p> Pt and Ir are the popular catalysts for electrochemical water splitting, but their low abundance on Earth&rsquo;s crust and high price render them unsustainable for future use. In the quest for alternative catalyst materials, a popular hydro-treating catalyst, molybdenum disulphide (MoS<sub>2</sub>), has been found to be promising for hydrogen evolution reaction (HER). Two types of MoS<sub>2</sub>-carbon composites, (i) physical mixture of MoS<sub>2</sub> and carbon black (Vulcan<sup>&reg;</sup>) and (ii) MoS<sub>2</sub> supported on reduced graphene oxide (RGO), were examined. Among the MoS<sub>2</sub>-based materials tested, 47 wt% MoS<sub>2</sub>/Vulcan<sup>&reg;</sup> gave the best performance in terms of current density at an encouraging level for practical application. The poor performance of bare MoS<sub>2</sub> was attributed to its poor electrical conductivity. No indication of performance deterioration was observed for 18 h of continuous operation at 2.0 V cell voltage with 47 wt% MoS<sub>2</sub>/Vulcan<sup>&reg;</sup>. MoS<sub>2</sub>/RGO hybrids showed HER activity, which was considerably higher than that of bare MoS<sub>2</sub>.</p>
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Unravelling the nature, evolution and spatial gradients of active species and active sites in the catalyst bed of unpromoted and K/Ba-promoted Cu/Al2O

  • Hyakutake, Tsuyoshi
  • van Beekc, Wouter
  • Urakawa, Atsushi
<p> CO<sub>2</sub> capture-reduction (CCR) is a recently developed catalytic process that combines two critical functions of CO<sub>2</sub> utilization path in one process, namely CO<sub>2</sub> capture and subsequent transformation (e.g. reduction by H<sub>2</sub>) into chemical fuels or intermediates such as CO. A bifunctional catalyst material is needed and the two functions are activated by means of an isothermal unsteady-state operation (i.e. gas switching). This work employs <em>operando</em> space- and time-resolved DRIFTS, XAFS, and XRD to elucidate the nature and functions of Cu and the promoters. Both unpromoted and K/Ba-promoted Cu/Al<sub>2</sub>O<sub>3</sub> catalysts were studied to illuminate the active surface species varying along the catalyst bed. The K promotor was found to uniquely facilitate efficient CO<sub>2</sub> capture in the form of surface formates, dispersion of active metallic Cu and suppression of surface Cu oxidation. The CO<sub>2</sub>-trapping efficiency of the K-promoted catalyst is so high that CO<sub>2</sub> capture takes place gradually along the catalyst bed towards the reactor outlet, hence creating large spatial and temporal gradients of surface chemical species. Understanding these features is of central importance to design efficient CCR catalysts. Furthermore, a completely different path for CO<sub>2</sub> reduction was evidenced for the unpromoted and Ba-promoted Cu catalysts where CO<sub>2</sub> can directly react with metallic Cu and oxidize its outer surface and thus releasing CO. These results also provide important new mechanistic insights into the widely investigated reverse water-gas shift reaction and the role that K and Ba promoters play.</p>
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Decrease of the required dopant concentration for δ-Bi2O3 stabilization through thermal quenching during single-step flame spray pyrolysis synthesis

  • Dreyer, Jochen A.H.
  • Pokhrel, Suman
  • Birkenstock, Johannes
  • Hevia, Miguel G.
  • Schowalter, Marco
  • Rosenauer, Andreas
  • Urakawa, Atsushi
  • Teoha, Wey Yang
  • Mädlerb, Lutz
<p> <em>&delta;</em>-Bi<sub>2</sub>O<sub>3</sub> is one of the best oxygen ion conductors known. However, due to its limited thermal stability and complicated synthesis techniques, the applications are limited. Here, the synthesis of stable nano-sized <em>&delta;</em>-Bi<sub>2</sub>O<sub>3</sub> using versatile and rapid flame spray pyrolysis (FSP) combined with <em>in-situ</em> Ti and/or Mn doping for an enhanced thermal stability is reported for the first time. Exceptionally low Bi replacing cation concentrations (8 at.% Ti) were sufficient to obtain phase-pure <em>&delta;</em>-Bi<sub>2</sub>O<sub>3</sub> which was attributed to the extraordinary high temperature gradient during FSP. The required cation amount for <em>&delta;</em>-phase stabilization was even further reduced by introducing mixtures of Mn and Ti (2.5 at.% Mn + 2.5 at.% Ti). Rietveld analysis revealed that the <em>&delta;</em>-Bi<sub>2</sub>O<sub>3</sub> structure is best represented by the <em>Fm</em><em>϶m</em> space group containing two closely neighbored <em>8c</em> and <em>32f</em> <em>Wyckoff</em> positions. Depending on the amount of Mn/Ti cations, about 25% of the possible oxygen positions remain vacant suggesting high bulk oxygen mobility. The enhanced oxygen mobility was confirmed by temperature programmed reduction (H<sub>2</sub>-TPR) with bulk reduction for <em>&delta;</em>-Bi<sub>2</sub>O<sub>3</sub> in contrast to exclusive surface reduction for <em>&beta;</em>-Bi<sub>2</sub>O<sub>3.</sub></p>
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Design, fabrication and charge recombination analysis of an interdigitated heterojunction nanomorphology in P3HT/PC70BM solar cells

  • Balderrama, Victor S.
  • Albero, Josep
  • Granero, Pedro
  • Ferré-Borrull, Josep
  • Pallarés, Josep
  • Palomares, Emilio
  • Marsal, Lluis F.
<div> In this work interdigitated heterojunction photovoltaic devices were manufactured. A donor layer of P3HT</div> <div> nanopillars was fabricated by soft nanoimprinting using nanoporous anodic alumina templates. Subsequently,</div> <div> the PC70BM acceptor layer was deposited by spin coating on top of the P3HT nanopillars using</div> <div> a solvent that would not dissolve any of the previous material. Anisole solvent was used because it does</div> <div> not dissolve the bottom donor layer of nanopillars and provides a good wettability between the two</div> <div> materials. Charge extraction was used to determine the charge carrier densities n on the interdigitated</div> <div> heterojunction under operating conditions. Moreover, transient photovoltage measurements were used</div> <div> to find the recombination rate constant in combination with the charge carrier density. At the same time,</div> <div> the interdigitated structure was also compared with bulk heterojunction and bilayer solar cells manufactured</div> <div> with the same polymeric and fullerene materials in order to understand the recombination loss</div> <div> mechanisms in the ordered and disordered nanomorphologies of the active layers.</div>
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