- Pyridine derivatives; New efficient additives in bromide/tribromide electrolyte for dye sensitized solar cells
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In this work, two new inexpensive pyridine derivatives, propyl isonicotinate (PIN) and isopropyl isonicotinate (IPIN), have been synthesized through a simple and low cost method and for the first time, they have been applied as effective additives in bromide/tribromide electrolyte in dye sensitized solar cells (DSSCs). Although the iodide/triiodide redox shuttle shows remarkable performance in DSSCs, but bromide/tribromide couple has a more positive redox potential in comparison to this couple. Therefore, it is good idea to design dyes whose HOMO and LUMO levels match with the redox potential of bromide/tribromide and the conduction band (CB) of TiO2, respectively. We have synthesized 3-(4-carbazole-9-yl-phenyl)-2-cyano-acrylic acid (TC301) and 2-cyano-3-(4-(3,6-di-tert-butyl-9H-carbazole-9-yl)phenyl) acrylic acid (TC302) as two carbazole dyes and applied them with modified electrolyte in DSSCs. The influence of PIN and IPIN additives in bromide/tribromide redox electrolyte on the DSSC performances is investigated. In comparison to electrolyte without additive, adding 0.5 M of these additives to the electrolyte solution leads to an increase in the open circuit voltage (Voc) and short current density (Jsc), consequently the energy conversion efficiency (η) improves. Electrochemical impedance spectroscopy show that the enhancement in Voc is due to increasing electron density in the CB of TiO2 so that a shift in the Fermi level (EF) occurs. It leads to a suppression in electron recombination that has beneficial effect on the Voc. Furthermore, cyclic voltammetry results reveal that PIN and IPIN has similar effect mechanisms to 4-tert-butylpyridine (TBP) additive in the DSSCs. Our findings show that TBP can be replaced with PIN and IPIN in the DSSCs.
- Bagheri, Omid,Dehghani, Hossein,Afrooz, Malihe
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p. 86191 - 86198
(2015/11/03)
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- 4-Pyridyl carbonyl and related compounds as thrips lures: Effectiveness for onion thrips and New Zealand flower thrips in field experiments
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On the basis of structural and/or aroma analogies to known thrips (Thysanoptera: Thripidae) lures, 35 compounds (18 pyridine derivatives, 13 benzene derivatives, and 4 other compounds), consisting of both synthetic and naturally occurring compounds, were screened for their ability to bring about increased thrips capture in field experiments using water traps in Canterbury, New Zealand. Most of the thrips caught were New Zealand flower thrips (NZFT) (Thrips obscuratus) or onion thrips (OT) (Thrips tabaci). The greatest increase in capture for NZFT (158 times for ♀ cf. to water control) was for the known lure ethyl nicotinate, a 3-pyridyl ester. Ethyl isonicotinate, the 4-pyridyl regioisomer of ethyl nicotinate, not previously reported as a thrips lure, provided the greatest increases in capture for OT (31 times) of any of the compounds tested, significantly more than ethyl nicotinate. Other 4-pyridyl carbonyl compounds, including ethyl 4-pyridyl ketone, also increased OT capture significantly. The natural floral compound cis-jasmone, which increased trap capture of NZFT (♀ 42 times, ♂ 25 times) but not OT, is reported as a thrips lure for the first time.
- Teulon, David A. J.,Davidson, Melanie M.,Hedderley, Duncan I.,James, Dale E.,Fletcher, Callum D.,Larsen, Lesley,Green, Vanessa C.,Perry, Nigel B.
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p. 6198 - 6205
(2008/12/23)
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- INSECT BEHAVIOUR MODIFYING COMPOUNDS
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The invention provides methods for controlling thrips populations using thrips-repelling and/or thrips-attracting agents. The agents are derivatives of pyridine. The invention also provides methods of preventing or minimising damage to plants by use of the same.
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Page/Page column 17
(2008/06/13)
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