Synthesis And Properties Of Photoelectric Materials Based On Arylamine Or Diketopyrrolopyrrole Units

A big global issue today is the upcoming depletion of fossil fuels and the energycrisis. Therefore, the challenges of21st century are to develop innovative materialsthat would provide new sources of clean sustainable energy and to develop newtechniques that can lead to efficient utilization of energy. Organic solar cells （OSCs）are a promising alternative to the fossil fuels for producing clean and renewableenergy from the sunlight and organic light-emitting diodes （OLEDs） have attracted agreat deal of attention because of their potential applications in energy-saving.This dissertation is focusing on the design and synthesis of new organicphotovoltaic materials and electroluminescent materials. The relationship between thestructure and the photoelectric properties were also studied. The results are as follows:1. A novel conjugated polymer of PBDT-TDPP-S was synthesized, which contains adonor unit of benzo[1,2-b:4,5-b’]dithiophene in main chain and an acceptor unitof diketopyrrolopyrrole in side chain. This kind of side-chain donor-acceptor（D-A） polymer exhibited better solution processability, lower HOMO level（5.34eV） and more balanced carrier mobility relative to its correspondingmain-chain D-A conjugated polymers. With a configuration of ITO/PEDOT:PSS/PBDT-TDPP-S:PC71BM/LiF/Al. A power conversion efficiency （PCE） of4.89%,an open-circuit voltage （Voc） of0.84V, a short-circuit current （Jsc） of10.04mAcm^-2and a fill factor （FF） of56.0%was achieved. Importantly, the FF is thehighest reported to date for side-chain D-A conjugated copolymers.2. A new donor-acceptor-donor ternary copolymer PTh-BDT-2DTDPP wassynthesized, in which two diketopyrrolopyrrole units were simultaneouslyincorporated into the side and main chains. The PTh-BDT-2DTDPP exhibited abroad absorption spectrum from300nm to850nm.With a configuration of ITO/PEDOT:PSS/PTh-BDT-2DTDPP:PC61BM/LiF/Al. A maximum PCE of4.36%with a high Vocof0.78V, a Jscof10.47mA cm^-2and FF of53.0%was achieved.3. Two donor/acceptor（D/A）-based benzo[1,2-b:4,5-b′]dithiophene-alt-2,3-biphenylquinoxaline copolymers were synthesized pending different functional groups（thiophene or triphenylamine） in the4-positions of phenyl rings. The poly（4,8-bis（（2-ethyl-hexyl）oxy）benzo[1,2-b:4,5-b]dithiophene）-alt-(2,3-bis（4-bis（N,N-bis（4-（octyloxy）phenylamino）-1,1-biphen-4-yl）quinoxaline）（P2） exhibited betterphotovoltaic performance than poly（4,8-bis（（2-ethylhexyl）oxy）benzo[1,2-b:4,5- b]dithiophene）-alt-（2,3-bis（4-（5-octylthiophen-2-yl） phenyl）quinoxaline）（P1） inthe bulk-heterojunction polymer solar cells with a configuration of ITO/PEDOT:PSS/polymers:[6,6]-phenyl-C71-butyric acid methyl ester （PC71BM）/LiF/Al. A PCE of3.43%, a Vocof0.80V and a Jscof9.20mA cm^-2were achievedin the P2-based cell. Importantly, this PCE level is2.29times higher than that inthe P1-based cell.4. A series of donor（D）-acceptor（A）-based polyfluorene derivatives, which containcarrier-transporting units of carbazole and oxadiazole as the substitutes of the C-9position of fluorene and are end-capped with the red-emitting iridium bi（phenyl-isoquilonato）（picolinato） unit by unconjugated linkage, were synthesized andcharacterized. The molar ratios between the donor of carbazole and the acceptorof oxadiazole moieties were found to significantly influence photoluminescentefficiency, electrochemical and electroluminescent properties of these D-A-basedpolyfluorene derivatives. While the ratio increased to3:7, the PFCz3OXD7Irshowed the best device performance in the polymer light-emitting device with aconfiguration of ITO/PEDOT/polymers/LiF/Al. A turn-on voltage of6.0V, amaximum current efficiency of0.59cd/A and the highest luminance of917cd/m2were presented.5. To study influence of the donor（D）-acceptor（A） units and pendent mode ofphosphorescent moiety on the opto-electronic properties for its resultingcopolymers, two D-A-based polyfluorene derivatives （P1and P2） pending thered-emitting iridium bi（phenylisoquilonato）（picolinato）[Ir（Piq）2（pic）] unit and apolyfluorene derivative （P3） only pending Ir（Piq）2（pic） unit were synthesizedand characterized, in which the donor of carbazole, the acceptor of oxadiazole aregrafted into the C-9position of fluorene, the Ir（Piq）2（pic） unit is pended intoeither the C-9position or the end of fluorene by unconjugated linkage,respectively. With a configuration of ITO/PEDOT/polymers/LiF/Al, the P1showed best electroluminescent properties. The maximum current efficiency of0.72cd/A and the highest luminance of1398cd/m2were obtained in theP1-based device, which are1.3and1.5times higher than those in the P2-baseddevice, respectively.