8 research outputs found
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<sup>–3</sup> 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 Cs<sub>2</sub>NaInCl<sub>6</sub> 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 (PC<sub>70</sub>BM) 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/PC<sub>70</sub>BM
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