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3982. Esej na maturi 2019Zoran Božič, Adrijana Špacapan, Andrej Adam, strokovna monografija Opis: Didaktična predstavitev romanov Francoski testament in Angel pozabe (tematski sklop za pisanje eseja iz slovenščine na splošni maturi 2019).
Ključne besede: didaktika, francoska književnost, Andrei Makine, roman, slovenska književnost, avstrijska književnost, Maja Haderlap, Zoran Božič, Adrijana Špacapan, druga svetovna vojna, prva svetovna vojna, nemška taborišča, ruski gulagi, partizanski odpor, posledice vojne, narodna manjšina, nacizem, stalinizem, diktatura, Pariz
Objavljeno v RUNG: 04.06.2018; Ogledov: 5693; Prenosov: 0
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3983. Surface modified titanium dioxide using transition metals : nickel as a winning transition metal for solar light photocatalysisAndraž Šuligoj, Iztok Arčon, Matjaž Mazaj, Goran Dražić, Denis Arčon, Pegie Cool, Urška Lavrenčič Štangar, Nataša Novak Tušar, 2018, izvirni znanstveni članek Opis: Titanium dioxide has been widely used as an antimicrobial agent, UV-filter and catalyst for pollution abatement. Herein, surface modifications with selected transition metals (Me) over colloidal TiO2 nanoparticles and immobilization with a colloidal SiO2 binder as composite films (MeTiO2/SiO2) on a glass carrier were used to enhance solar-light photoactivity. Colloidal TiO2 nanoparticles were modified by loading selected transition metals (Me ¼ Mn, Fe, Co, Ni, Cu, and Zn) in the form of chlorides on their surface. They were present primarily as oxo-nanoclusters and a portion as metal oxides. The structural characteristics of bare TiO2 were preserved up to an optimal metal loading of 0.5 wt%. We have shown in situ that metal-oxo-nanoclusters with a redox potential close to that of O2/O2 were able to function as co-catalysts on the TiO2 surface which was excited by solar-light irradiation. The materials were tested for photocatalytic activity by two opposite methods; one detecting O2 (reduction, Rz ink test) while the other detecting OH (oxidation, terephthalic acid test). It was shown that the enhancement of the solar-light activity of TiO2 by the deposition of transition metal oxo-nanoclusters on the surface depends strongly on the combination of the reduction potential of such species and appropriate band positions of their oxides. The latter prevented excessive self-recombination of the photogenerated charge carriers by the nanoclusters in Ni and Zn modification, which was probably the case in other metal modifications.
Overall, only Ni modification had a positive effect on solar photoactivity in both oxidation and reduction reactions.
Ključne besede: surface modified TiO2, XANES, EXAFS, Nickel, solar light photocatalyst
Objavljeno v RUNG: 01.06.2018; Ogledov: 3547; Prenosov: 0
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3984. Polysulfides formation in different electrolytes from the perspective of X-ray absorption spectroscopyRobert Dominko, Alen Vižintin, Giuliana Aquilanti, Lorenzo Stievano, Maria Joseph Helen, Anji Reddy Munnangi, Maximilian Fichtner, Iztok Arčon, 2018, izvirni znanstveni članek Opis: Li-S batteries are promising energy storage technology for the future, however there two major problems remained which need to be
solved before successful commercialization. Capacity fading due to polysulfide shuttle and corrosion of lithium metal are directly
connected with the type and quantity of electrolyte used in the cells. Several recent works show dependence of the electrochemical
behavior of Li-S batteries on type of the electrolyte. In this work we compare and discuss a discharge mechanism of sulfur conversion
in three different electrolytes based on measurements with sulfur K-edge XAS. The sulfur conversion mechanism in the ether based
electrolytes, the most studied type of solvents in the Li-S batteries, which are enabling high solubility of polysulfides are compared
with the fluorinated ether based electrolytes with a reduced polysulfide solubility and in carbonate based electrolytes with the sulfur
confined into a ultramicroporous carbon. In all three cases the sulfur reduction proceeds through polysulfide intermediate phases
with a difference on the type polysulfides detected at different steps of discharge.
Ključne besede: Li-S batteries, operando sulphur K-edge XANES, EXAFS, Li-polysulphides
Objavljeno v RUNG: 01.06.2018; Ogledov: 3623; Prenosov: 0
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3985. Določanje atomske strukture snovi z rentgensko absorpcijsko spektrometrijo s sinhrotronsko svetloboIztok Arčon, predavanje na tuji univerzi Opis: Zakaj so velike evropske države pripravljene investirati ogromna sredstva v izgradnjo in delovanje sinhrotronov? Gre za izjemno svetle vire ultravijolične in rentgenske svetlobe, ki so v zadnjih dveh ali treh desetletjih postali nepogrešljivo orodje pri analizi snovi na atomskem oziroma molekularnem nivoju. Razvoja in sinteze novih materialov z želenimi lastnostmi si ne moremo predstavljati brez sodobnih preiskovalnih metod, ki temeljijo na sinhrotronski svetlobi.
V predavanju bo predstavljen princip delovanja in primeri uporabe ene od rentgenskih metod s sinhrotronsko svetlobo – rentgensko absorpcijsko spektroskopijo, s katero lahko določamo atomsko oz. molekularno strukturo snovi v vseh agregatnih stanjih. Za take raziskave so danes zanimivi predvsem različni nanostrukturni materiali, kot so katalizatorji, katodni materiali za Li-ionske in Li-žveplove baterije, tanke zaščitne plasti, in drugi, pri katerih atomska struktura določa njihove funkcionalne lastnosti. Na predavanju bodo izpostavljeni v prvi vrsti primeri in-operando karakterizacije z metodama XANES in EXAFS ki omogoča zelo natančno in neposredno spremljanje postopnih sprememb valence kovinskih kationov in njihove lokalne atomske strukture v nanozrnih v katodnem materialu med polnjenjem in praznjenjem baterije, ali kovinskih kationov na površini nanostrukturnega (foto)katalitskega materiala med samo katalitsko reakcijo.
Sodobni sinhrotronski viri rentgenske svetlobe pa omogočajo tudi uporabo kombinacije rentgenske absorpcijske spektroskopije z rentgenskimi mikroskopskimi metodami, z ločljivostjo do nekaj deset nanometrov. Na predavanju bodo predstavljeni primeri mikro-XANES in EXAFS analize lokalizacije in vezave toksičnih kovinskih kationov na sub-celičnem nivoju v različnih tkivih rastlin, s čimer lahko ključno prispevamo k razumevanju mehanizmov zajemanja, transporta, akumulacije in kompleksacije kovinskih kationov na sub-celičnem nivoju v različnih tkivih rastlin, ki te polutante (hiper)akumulirajo, in jih s tem prenašajo v prehranjevalno verigo, s čimer je ogroženo zdravje ljudi.
Ključne besede: rentgenska absorpcijska spektroskopija, XANES, EXAFS, strukturna analiza, sinhrotronska svetloba
Objavljeno v RUNG: 01.06.2018; Ogledov: 4318; Prenosov: 0
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3986. The effect of polymer molecular weight on the performance of PTB7-Th:O-IDTBR non-fullerene organic solar cellsSebastian F. Hoefler, Egon Pavlica, Gvido Bratina, 2018, izvirni znanstveni članek Opis: Recent advances in the development of non-fullerene acceptors have increased the power conversion efficiency of organic solar cells to approximately 13%. Fullerene-derivatives and non-fullerene acceptors possess distinctively different structural, optical and electronic properties, which also change the requirements on the polymer donor in non-fullerene organic solar cells. Therefore, in this study, the effect of the molecular weight of the conjugated polymer on the photovoltaic performance, charge carrier mobility, crystallization properties, film morphology, and non-geminate recombination dynamics is systematically investigated in polymer:small molecule organic solar cells using the low bandgap polymer PTB7-Th as the donor and the non-fullerene indacenodithiophene-based small molecule O-IDTBR as the acceptor. Among the examined polymer samples (50–300 kDa), high molecular weights of PTB7-Th (with an optimum molecular weight of 200 kDa) are advantageous to achieve high efficiencies up to 10%, which can be correlated with an increased crystallinity, an improved field-effect hole mobility (1.05 × 10−2 cm2 V−1 s−1), lower charge carrier trapping and a reduced activation energy of charge transport (98 meV). Bias-assisted charge extraction and transient photovoltage measurements reveal higher carrier concentrations (1016 cm−3) and long lifetimes (4.5 μs) as well as lower non-geminate recombination rate constants in the corresponding devices, supporting the high photocurrents (ca. 15.2 mA cm−2) and fill factors (>60%).
Ključne besede: organski polprevodniki, gibljivost, organske sončne celice
Objavljeno v RUNG: 28.05.2018; Ogledov: 4437; Prenosov: 0
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