| 2031. |
- Hou, Lili, 1984, et al.
(författare)
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Optically Switchable NIR Photoluminescence of PbS Semiconducting Nanocrystals using Diarylethene Photoswitches
- 2022
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 144:39, s. 17758-17762
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Tidskriftsartikel (refereegranskat)abstract
- Precisely modulated photoluminescence (PL) with external control is highly demanded in material and biological sciences. However, it is challenging to switch the PL on and off in the NIR region with a high modulation contrast. Here, we demonstrate that reversible on and off switching of the PL in the NIR region can be achieved in a bicomponent system comprised of PbS semiconducting nanocrystals (NCs) and diarylethene (DAE) photoswitches. Photoisomerization of DAE to the ring-closed form upon UV light irradiation causes substantial quenching of the NIR PL of PbS NCs due to efficient triplet energy transfer. The NIR PL fully recovers to an on state upon reversing the photoisomerization of DAE to the ring-open form with green light irradiation. Importantly, fully reversible switching occurs without obvious fatigue, and the high PL on/off ratio (>100) outperforms all previously reported assemblies of NCs and photoswitches.
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| 2032. |
- Keller, Jan, et al.
(författare)
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Rubidium Fluoride Absorber Treatment for Wide-Gap (Ag,Cu)(In,Ga)Se-2 Solar Cells
- 2022
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Ingår i: Solar RRL. - : John Wiley & Sons. - 2367-198X. ; 6:6
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Tidskriftsartikel (refereegranskat)abstract
- This contribution studies the potential of an RbF postdeposition treatment (RbF-PDT) of wide-gap (Ag,Cu)(In,Ga)Se-2 (ACIGS) absorbers to improve the corresponding solar cell performance. While a higher open-circuit voltage (V-OC) and short-circuit current density are achieved, a lower fill factor (FF) is observed for most of the devices subjected to an RbF-PDT. However, the drop in FF can be avoided for some close-stoichiometric samples, leading to maximum efficiencies beyond 16% (without antireflection coating) at a bandgap energy (E-g) of 1.43 eV. For off-stoichiometric ACIGS, a record V-OC value of 926 mV at E-g = 1.44 eV is reached. Lower V-OC deficits likely require enhanced bulk quality of wide-gap chalcopyrite absorbers. Extensive material analysis shows that the heavy alkali PDT of ACIGS with high Ag and Ga contents leads to similar absorber modifications as commonly observed for low-gap Cu(In,Ga)Se-2 (CIGS). Rubidium is continuously distributed at "internal" (grain boundaries) and "external" (buffer and back contact) absorber interfaces. The results indicate that Rb diffusion into the absorber bulk (including 1:1:2 and 1:3:5 compounds) is restricted. Furthermore, the formation of a very thin RbInSe2 surface layer is suggested. It remains open, which effects alter the device characteristics after RbF-PDT.
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| 2033. |
- Li, Zhaojun, 1989, et al.
(författare)
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High-photovoltage all-polymer solar cells based on a diketopyrrolopyrrole-isoindigo acceptor polymer
- 2017
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 5:23, s. 11693-11700
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we synthesized and characterized two new n-type polymers PTDPP-PyDPP and PIID-PyDPP. The former polymer is composed of pyridine-flanked diketopyrrolopyrrole (PyDPP) and thiophene-flanked diketopyrrolopyrrole (TDPP). The latter polymer consists of PyDPP and isoindigo (IID). PIID-PyDPP exhibits a much higher absorption coefficient compared to the widely used naphthalene diimide (NDI)-based acceptor polymers, and its high-lying LUMO level affords it to achieve a high open-circuit voltage (Voc). As a result, an all-polymer solar cell (all-PSC) fabricated from a high band gap polymer PBDTTS-FTAZ as the donor and PIID-PyDPP as the acceptor attained a high Voc of 1.07 V with a power conversion efficiency (PCE) of 4.2%. So far, it has been one of the highest PCEs recorded from all-PSCs using diketopyrrolopyrrole (DPP)-based acceptors. Gratifyingly, no obvious PCE decay was observed in two weeks, unraveling good stability of the all-PSC. This work demonstrates that the electron-withdrawing PyDPP unit can be a promising building block for new acceptor polymers in all-PSCs.
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| 2034. |
- Ma, Chunyan, et al.
(författare)
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CO2 Separation by a Series of Aqueous Morpholinium-Based Ionic Liquids with Acetate Anions
- 2020
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 8:1, s. 415-426
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Tidskriftsartikel (refereegranskat)abstract
- In this work, CO2 absorption capacities in a series of aqueous N-alkyl-N-methylmorpholinium-based ILs with acetate as the counterpart anion were investigated. Among these ILs, N-butyl-N-methylmorpholinium acetate ([Bmmorp][OAc]) with the highest CO2 absorption capacity was screened for thermodynamic modeling. The non-random two-liquid model and the Redlich–Kwong equation of state (NRTL-RK model) were used to describe the phase equilibria. The CH4 absorption capacity in the aqueous [Bmmorp][OAc] was also measured in order to verify the results predicted from the thermodynamic modeling, and the comparison shows the reliability of the model prediction. The parameters were embedded into the commercial software Aspen Plus. After that, the aqueous [Bmmorp][OAc] solutions with 30–40 wt % of water were selected to carry out process simulation for CO2 separation from biogas, and it was found that using these aqueous [Bmmorp][OAc] gave rise to lower energy usage and smaller size of equipment than other physical solvents. The results suggest that aqueous [Bmmorp][OAc] solution can be used as an alternative to organic solvents and has the potential to decrease the cost of CO2 separation.
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| 2035. |
- Monti, Damien, et al.
(författare)
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Multivalent Batteries-Prospects for High Energy Density: Ca Batteries
- 2019
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Ingår i: Frontiers in Chemistry. - : Frontiers Media SA. - 2296-2646. ; 7:FEB
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Tidskriftsartikel (refereegranskat)abstract
- Batteries based on Ca hold the promise to leapfrog ahead regarding increases in energy densities and are especially attractive as Ca is the 5th most abundant element in the Earth's crust. The viability of Ca metal anodes has recently been shown by approaches that either use wide potential window electrolytes at moderately elevated temperatures or THE-based electrolytes at room temperature. This paper provides realistic estimates of the practical energy densities for Ca-based rechargeable batteries at the cell level, calculated using open source models for several concepts. The results from the Ca metal anode batteries indicate that doubled or even tripled energy density as compared to the state-of-the-art Li-ion batteries is viable if a practical proof-of-concept can be achieved.
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| 2036. |
- Peng, Cheng, 1993, et al.
(författare)
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Aqueous Asymmetric Supercapacitors with Pyrenetetraone-Derived Pseudocapacitive Polymer-Functionalized Graphene Cathodes Enabling a 1.9 V Operating Window
- 2024
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Ingår i: Advanced Energy and Sustainability Research. - 2699-9412. ; 5:4
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Tidskriftsartikel (refereegranskat)abstract
- Pseudocapacitive polymers have garnered significant attention in the realm of supercapacitors due to their versatile molecular design capabilities, cost-effectiveness, and impressive electrical conductivity. However, limited by the low capacity and short cycle life, the investigation on conducting polymers for potential electrode materials is still insufficient. Herein, a series of pyrenetetraone-derived polymers with pyrazine units are designed and synthesized. Furthermore, UV–vis spectroscopy demonstrates the different interaction behavior between the polymers and reduced graphene oxide (rGO), which can further indicate the performance difference of the composite electrodes. As a result, the pseudocapacitive polymer/rGO composite electrode (2/1 PPYT/rGO) exhibits a high specific capacitance of 591 F g−1 at 1 A g−1 in a 1 m sulfuric acid electrolyte. The asymmetric supercapacitor (ASC) assembled by the 2/1 PPYT/rGO cathode and the annealed Ti3C2Tx anode (2/1 PPYT/rGO//A-Ti3C2Tx) delivers an excellent energy density of 38.1 Wh kg−1 at a power density of 950 W kg−1. Additionally, both devices demonstrate outstanding stability, retaining over 90% of their capacity after 15 000 charge/discharge cycles. As a result, these carefully engineered organic polymers, with their well-thought-out structural designs, showcase exceptional electrochemical performance, positioning them as highly promising candidates for the next generation of high-performance energy storage materials.
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| 2037. |
- Pohl, Johannes
(författare)
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Effects of ozonated sewage effluents and pharmaceuticals in zebrafish (Danio rerio)
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The aquatic environment is the main destination for many organic pollutants originating from human activity. Pharmaceuticals are significant contributors to this pollutant cocktail. One major route of pharmaceuticals into the aquatic environment is through discharges from sewage treatment plants (STPs) with inadequate pharmaceutical removal capacity. Adverse effects in aquatic organisms exposed to pharmaceuticals have been illustrated in a multitude of studies. Advanced sewage treatment technologies are therefore being evaluated as potential methods for improving pharmaceutical removal, for example whole-effluent ozonation. However, it remains important to assess how the ozonation treatment modulates the biological effect in aquatic organisms exposed to the STP effluent due to the formation of ozonation by-products (OBPs). This thesis aimed to investigate outcomes of ozonation treatment of STP effluents with a special focus on pharmaceuticals, by combining chemical analysis and in vivo testing using zebrafish (Danio rerio). Firstly the effects of an ozonated STP effluent on reproduction and behavior of adult zebrafish were evaluated at a Swedish STP (Knivsta municipal STP) with a full-scale ozonation step. Fish exposed over 21 days to the ozonated STP effluent spawned significantly more eggs than fish exposed to the nonozonated effluent and tap water. Vitellogenin induction (a biomarker for estrogenic pollutants) and a possible anxiety-related behavior were also observed in fish exposed to the ozonated STP effluent. Chemical analysis of the pre- and post ozonated STP effluent was used to screen for the presence of 105 pharmaceuticals, of which 24 could be detected. The average ozone removal efficiency of these pharmaceuticals was 77%. The thesis work then focused on how ozonation would affect zebrafish embryotoxicity of three pharmaceuticals detected in the Knivsta STP effluent (i.e. carbamazepine, diclofenac, and oxazepam). While embryotoxicity of diclofenac was eliminated, exposure to oxazepam and carbamazepine induced embryotoxic responses following ozonation, suggesting formation of OBPs. The thesis therefore proceeded to investigate the toxicities of isolated carbamazepine OBPs. It was revealed that two carbamazepine OBPs, BQM and BQD, were the drivers of ozonated carbamazepine embryotoxicity. The thesis concludes that the formation of specific pharmaceutical OBPs explains adverse biological outcomes of effluent ozonation. The results add valuable information for the continuing efforts to improve STP effluent treatment.
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| 2038. |
- Wang, Chuanfei, 1986-, et al.
(författare)
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Ternary Organic Solar Cells with Minimum Voltage Losses
- 2017
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Ingår i: Advanced Energy Materials. - : Wiley. - 1614-6832 .- 1614-6840. ; 7:21
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Tidskriftsartikel (refereegranskat)abstract
- A new strategy for designing ternary solar cells is reported in this paper. A low-bandgap polymer named PTB7-Th and a high-bandgap polymer named PBDTTS-FTAZ sharing the same bulk ionization potential and interface positive integer charge transfer energy while featuring complementary absorption spectra are selected. They are used to fabricate efficient ternary solar cells, where the hole can be transported freely between the two donor polymers and collected by the electrode as in one broadband low bandgap polymer. Furthermore, the fullerene acceptor is chosen so that the energy of the positive integer charge transfer state of the two donor polymers is equal to the energy of negative integer charge transfer state of the fullerene, enabling enhanced dissociation of all polymer donor and fullerene acceptor excitons and suppressed bimolecular and trap assistant recombination. The two donor polymers feature good miscibility and energy transfer from high-bandgap polymer of PBDTTS-FTAZ to low-bandgap polymer of PTB7-Th, which contribute to enhanced performance of the ternary solar cell.
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| 2039. |
- Alkadir Abdulahi, Birhan, 1985, et al.
(författare)
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Open-Circuit Voltage Modulations on All-Polymer Solar Cells by Side Chain Engineering on 4,8-Di(thiophen-2-yl)benzo[1,2- b:4,5- b′]dithiophene-Based Donor Polymers
- 2018
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 1:6, s. 2918-2926
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, all-polymer solar cells (all-PSCs), incorporating active layers based on blends of electron-donor (D) and acceptor (A) polymers, have drawn attention because of the advantages they hold in the flexibility of choosing the D:A combinations to modulate their energy levels and to improve their overall open-circuit voltages (V oc ) and power conversion efficiencies (PCE)s. V oc is one of the key parameters for the determination of the PCEs of PSCs. In this work, we synthesized six donor polymers with three different side chains appended to the 4,8-di(thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene (BDT) units. By substituting carbon with sulfur and silicon atoms at the 5-position of the thiophenes attached to the BDT units, the highest occupied molecular orbital (HOMO) levels of the donor polymers could be successfully lowered. As anticipated, the V oc values of the resulting all-PSCs increased along with the lowering of the HOMO levels of the donor polymers. Among the six all-PSCs, the PBDT-BDD:PNDI-T10 all-PSC realized a balance between the photovoltage and photocurrent, where a decent PCE of 5.6% was obtained with a V oc of 0.9 V and a photocurrent of 10.5 mA/cm 2 .
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| 2040. |
- Barnoos, Vahid, et al.
(författare)
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The deterioration process of limestone in the Anahita Temple of Kangavar (West Iran)
- 2020
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Ingår i: Heritage Science. - : Springer Science and Business Media LLC. - 2050-7445. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The well-known archaeological site of Anahita Temple at Kangavar is one of the most important Iranian stone monuments. It has been dated by various authors in an interval extended from Achaemenid to Sasanian Persian Empires (sixth century BCE to seventh century AD). Significant weathering has been occurred in various stone blocks used in the construction of this monument. The aim of this research is to study the deterioration process of the stone blocks used in the Temple. It includes chemical and mineralogical analysis of stones, characterization of deterioration patterns and processes, and identification of factors influenced theprocess. Results have been obtained by on-site and laboratory studies, including optical microscopy, petrography, X-ray fluorescence, X-ray diffraction and scanning electron microscopy coupledwith energy dispersive X-ray spectroscopy methods. They showed that low-porosity limestone and dolomitic limestone have been used in the construction of the Temple, which have a compact micritic structure with variable size calcite veins (sparite) and clay veins. According to the on-site and laboratory studies, the deterioration patterns are partially similar in majority of the stone blocks and include different types of detachments as well as biological colonisations. The multianalytical results proved that the deterioration process is mainly of physical weathering type, due to structural and chemical characteristics of the limestone as well as climate factors, temperature fluctuations in particular. It turned out that limestone characteristics (including presence of clay veins as well as heterogeneity of calcitic matrix (micrite and sparite)) can affect the behaviour of stone blocks against climate factors; helping us to find reasons behind physical weathering of limestone in the cultural/historical sites and monuments.
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