Study On Synthesis And Photovoltaic Performance Coumarins Types Sensitized Dyes With Azole ?-bridge

In recent years,Dye Sensitized Solar Cell(DSSC)has drawn more and more attention and it has been considered as the powerful competitor to the silicon cell because of low cost,flexible modification and high photo-electricity conversion efficiency.Sensitizing dye,which absorbs sunlight to excite the photoelectron,is a dispensable component in achieving high photo-electricity conversion efficiency in DSSC.A series of 6 novel coumarin-type dyes were synthesized with coumarin donor,azole bridge and cyanoacetic acid or rhodanine acetic acid acceptor.Their structures were characterized with NMR and LC-MS and their spectral properties,electrochemical properties and photovoltaic performance were measured and investigated systematically.The relationship between structure and activity were analysized.Three novel diethylaminocoumarin sensitizing dyes were synthesized with coumarin donor,benzimidazole bridges linked with phenyl,thienyl,furyl group,and cyanoacetic acid acceptor.4-Diethylamino-salicylaldehyde reacted with4-bromo-o-phenylenediamine,ethyl cyanoacetate to get 7-diethylamino-3-(5-bromobenzo imidazole)-coumarin.Then the coumarin compound reacted with(4-formylphenyl)boronic acid ?(4-formylthiophene)boronic acid or(5-formylfuran-2-yl)boronic acid and respectively by Suzuki coupling to obtain the aledhydes.At last,three novel sensitized dyes were synthesized through the Knoevenagel condensation reaction between the aldehydes and cyanoacetic acid.The spectrum and photovoltaic performance were investigated systematically.The results showed that dye CAC-B with diethylamino coumarin donor,benzimidazole bridge linked phenyl group,cyanoacetic acid acceptor shows the most efficient photo-electricity conversion efficiency(Jsc=4.86 mA/cm2,Voc=0.65 V,ff = 0.72,?=2.23%).Two novel diethylaminocoumarin sensitizing dyes were synthesized with diethylamino coumarin donor,2-thienyl-thiazole bridge,and cyanoacetic acid or rhodanine acetic acid acceptor.4-Diethylamino-substituted salicyladehyde reacted with ethyl acetoacetate to obtain the 3-acetly-7-diethylamino coumarin.After the bromination of acetyl group,the coumarin derivative was introduced ?-bridge of2-thienyl-thiazole through Hantzsch reaction with thiophene-2-thiocarboxamide.An aldehyde group was introduced on the thiophene ring with Vilsmier reagent.At last two sensitizing dyes were synthesized through Knoevenagel condensation of the aldehyde intermediate with cyanoacetic acid or rhodanine acetic acid.The spectrum and photovoltaic performance were investigated systematically.The results showed that dye CIC-L with diethylamino coumarin donor,2-thienyl-thiazole bridge,cyanoacetic acid acceptor shows more efficient photo-electricity conversion efficiency(Jsc=9.79 mA/cm2,Voc=0.69 V,ff = 0.71,?=4.78%).One novel coumarin sensitizing dye was synthesized with rigid nitrogen-containg ring substituted coumarin donor,thiophene bridge,and malonic acid acceptor.3-Hydroxy-N,N-bis(3-methylbut-2-en-1-yl)benzeneaminium bromide was prepared from m-aminophenol and 1-bromo-3-methyl-2-butene via nucleophilic substitution reaction and then was transformed into9-formyl-8-hydroxy-1,1,7,7-tetramethyljulolidine through electrophilic substitution and subsequent Vilsmeir reaction.Julolidine derivatives condensed with 2-thiophene acetonitrile to synthesize coumarin derivatives.After the introduction of the aldehyde group,the coumarin derivative condensed with malonic acid to give KR-1.The spectrum and photovoltaic performance were investigated systematically and compared with those of the similar compound ZX-1 with diethylaminocoumarin as donor and cyanoacetic acid as acceptor.The result showed that dye KR-1 with rigidnitrogen-containgcoumarin ring substituted coumarin donor,thiophene bridge and malonic acid acceptor shows higher photo-electricity conversion efficiency(Jsc=9.11 mA/cm2,Voc=0.62 V,ff = 0.72,?=4.02%).