EL MARMON EN TAFIRA [Material gráfico]

ÁLBUM FAMILIAR CASA DE COLÓNCopia digital. Madrid : Ministerio de Educación, Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 201

Bimetallic Mn-Ce loaded on different zeolite carriers applied in the toluene abatement in air by non–thermal plasma DDBD Reactor

A sequence of zeolite carriers (Carrier = ZSM-5, Small crystal ZSM-5, MCM-41, SBA-15) were used to support active metals Mn-Ce, which have presented an enormous potential for plasma oxidation of toluene in air. The prepared samples were detected by means of N2 adsorption-desorption, SEM, XPS, H2-TPR, etc. Through the activity evaluation in the Non-thermal Plasma Reactor, we found that the catalysts with different carriers showed distinct degradation activities. The performance of mesoporous supported catalysts was better than that of microporous catalysts, of which MCM-41 performed best. 96.3% of toluene can be decomposed, and 97.3% of degraded toluene converted into final products CO2 completely at the initial concentration of 1000 ppm and SIE of 9 kJ/L. From the results, we can see that the appropriate carrier is conducive to maximizing the efficiency of the active metal, and Mn-Ce/MCM-41 got the best performance in the plasma catalysis for toluene abatement.</p

Morphology Determines Conductivity and Seebeck Coefficient in Conjugated Polymer Blends

The impact of nanoscale morphology on conductivity and Seebeck coefficient in p-type doped all-polymer blend systems is investigated. For a strongly phase separated system (P3HT:PTB7), we achieve a Seebeck coefficient that peaks at <i>S</i> ∼ 1100 μV/K with conductivity σ ∼ 3 × 10^–3 S/cm for 90% PTB7. In marked contrast, for well-mixed systems (P3HT:PTB7 with 5% diiodooctane (DIO), P3HT:PCPDTBT), we find an almost constant <i>S</i> ∼ 140 μV/K and σ ∼ 1 S/cm despite the energy levels being (virtually) identical in both cases. The results are interpreted in terms of a variable range hopping (VRH) model where a peak in <i>S</i> and a minimum in σ arise when the percolation pathway contains both host and guest sites, in which the latter acts as energetic trap. For well-mixed blends of the investigated compositions, VRH enables percolation pathways that only involve isolated guest sites, whereas the large distance between guest clusters in phase-separated blends enforces (energetically unfavorable) hops via the host. The experimentally observed trends are in good agreement with the results of atomistic kinetic Monte Carlo simulations accounting for the differences in nanoscale morphology

Energy Level Alignment of N‑Doping Fullerenes and Fullerene Derivatives Using Air-Stable Dopant

Doping has been proved to be one of the powerful technologies to achieve significant improvement in the performance of organic electronic devices. Herein, we systematically map out the interface properties of solution-processed air-stable n-type (4-(1,3-dimethyl-2,3-dihydro-1<i>H</i>-benzoimidazol-2-yl)­phenyl) doping fullerenes and fullerene derivatives and establish a universal energy level alignment scheme for this class of n-doped system. At low doping levels at which the charge-transfer doping induces mainly bound charges, the energy level alignment of the n-doping organic semiconductor can be described by combining integer charger transfer-induced shifts with a so-called double-dipole step. At high doping levels, significant densities of free charges are generated and the charge flows between the organic film and the conducting electrodes equilibrating the Fermi level in a classic “depletion layer” scheme. Moreover, we demonstrate that the model holds for both n- and p-doping of π-backbone molecules and polymers. With the results, we provide wide guidance for identifying the application of the current organic n-type doping technology in organic electronics

DNA Based Hybrid Material for Interface Engineering in Polymer Solar Cells

A new solution processable electron transport material (ETM) is introduced for use in photovoltaic devices, which consists of a metallic conjugated polyelectrolyte, poly­(4-(2,3-dihydrothieno­[3,4-<i>b</i>]­[1,4]­dioxin-2-yl-methoxy)-1-butanesulfonic acid (PEDOT-S), and surfactant-functionalized deoxyribonucleic acid (DNA) (named DNA:CTMA:PEDOT-S). This ETM is demonstrated to effectively work for bulk-heterojunction organic photovoltaic devices (OPV) based on different electron acceptor materials. The fill factor, the open circuit voltage, and the overall power conversion efficiency of the solar cells with a DNA:CTMA:PEDOT-S modified cathode are comparable to those of devices with a traditional lithium fluoride/aluminum cathode. The new electron transport layer has high optical transmittance, desired work function and selective electron transport. A dipole effect induced by the use of the surfactant cetyltrimethylammonium chloride (CTMA) is responsible for lowering the electrode work function. The DNA:CTMA complex works as an optical absorption dilutor, while PEDOT-S provides the conducting pathway for electron transport, and allows thicker layer to be used, enabling printing. This materials design opens a new pathway to harness and optimize the electronic and optical properties of printable interface materials

Spin Centers in Vanadium-Doped Cs₂NaInCl₆ Halide Double Perovskites

We provide direct evidence for a spin-active V4+ defect center, likely in the form of a VO2+ complex, predominantly introduced in single crystals of vanadium-doped Cs2NaInCl6 halide double perovskites grown by the solution-processed hydrothermal method. The defect has C4v point group symmetry, exhibiting an electron paramagnetic resonance (EPR) spectrum arising from an effective electron spin of S = 1/2 and a nuclear spin of I = 7/2 (corresponding to 51V with nearly 100% natural abundance). The determined electron g-factor and hyperfine parameter values are g⊥= 1.973, g∥ = 1.945, A⊥ = 180 MHz, and A∥ = 504 MHz, with the principal axis z along a ⟨001⟩ crystallographic axis. The controlled growth of V-doped Cs2NaInCl6 in an oxygen-free environment is shown to suppress the V4+ EPR signal. The defect model is suggested to have a VOCl5 octahedral coordination, where one of the nearest-neighbor Cl– of V is replaced by O2–, with octahedral compression along the V–O axis. This VO complex formation competes with the isolated V3+ substitution of In3+, which in turn provides a means for the charge-state tuning of V ions. This finding calls for a better understanding and control of defect formation in solution-grown halide double perovskites, which is critical for optimizing and tailoring material design for solution-processable optoelectronics and spintronics

The Effect of Oxygen Uptake on Charge Injection Barriers in Conjugated Polymer Films

The energy offset between the electrode Fermi level and organic semiconductor transport levels is a key parameter controlling the charge injection barrier and hence efficiency of organic electronic devices. Here, we systematically explore the effect of in situ oxygen exposure on energetics in n-type conjugated polymer P­(NDI2OD-T2) films. The analysis reveals that an interfacial potential step is introduced for a series of P­(NDI2OD-T2) electrode contacts, causing a nearly constant downshift of the vacuum level, while the ionization energies versus vacuum level remain constant. These findings are attributed to the establishment of a so-called double-dipole step via motion of charged molecules and will modify the charge injection barriers at electrode contact. We further demonstrate that the same behavior occurs when oxygen interacts with p-type polymer TQ1 films, indicating it is possible to be a universal effect for organic semiconductors

Reduction of Charge-Carrier Recombination at ZnO–Polymer Blend Interfaces in PTB7-Based Bulk Heterojunction Solar Cells Using Regular Device Structure: Impact of ZnO Nanoparticle Size and Surfactant

Cathode interfacial layers, also called electron extraction layers (EELs), based on zinc oxide (ZnO) have been studied in polymer-blend solar cells toward optimization of the opto-electric properties. Bulk heterojunction solar cells based on poly­({4,8-bis­[(2-ethylhexyl)­oxy]­benzo­[1,2-<i>b</i>:4,5-b′]­dithiophene-2,6-diyl}­{3-fluoro-2-[(2-ethylhexyl)­carbonyl]­thieno­[3,4-<i>b</i>]­thiophenediyl}) (PTB7) and [6,6]-phenyl-C71-butyric acid methyl ester (PC₇₀BM) were realized in regular structure with all-solution-processed interlayers. A pair of commercially available surfactants, ethanolamine (EA) and ethylene glycol (EG), were used to modify the surface of ZnO nanoparticles (NPs) in alcohol-based dispersion. The influence of ZnO particle size was also studied by preparing dispersions of two NP diameters (6 versus 11 nm). Here, we show that performance improvement can be obtained in polymer solar cells via the use of solution-processed ZnO EELs based on surface-modified nanoparticles. By the optimizing of the ZnO dispersion, surfactant ratio, and the resulting morphology of EELs, PTB7/PC₇₀BM solar cells with a power-conversion efficiency of 8.2% could be obtained using small sized EG-modified ZnO NPs that allow the clear enhancement of the performance of solution-processed photovoltaic devices compared to state-of-the-art ZnO-based cathode layers