2010/01/04 by Daniel Ayuk Mbi Egbe, Daniel A. M. Egbe, Stefan Türk +14 · 9 citations
Engineering · Materials Science · #Organic Electronics and Photovoltaics #Conducting polymers and applications #Perovskite Materials and Applications
paper · doi:10.1021/ma902273s
This article reports on the synthesis, characterization and properties of a series of anthracene−containing poly( p -phenylene-ethynylene)- alt -poly( p -phenylene-vinylene)s (PPE−PPV) copolymers with general constitutional unit (Ph−C≡C−Anthr−C≡C−Ph−CH═CH−Ph−CH═CH−) n denoted AnE-PV . Solely linear ( AnE-PV aa, - ad, - ae ) and solely branched ( AnE-PV bb ) as well as mixed linear and branched ( AnE-PV ab, - ac, - ba, - cc ) alkoxy side chains were grafted to the backbone in order to tune the π−π-stacking ability of the materials. It has been possible to establish a correlation between π−π-stacking ability, absorptive behavior, charge carrier mobility, solar cell active layer nanoscale morphology and resulting photovoltaic performance. Solar cells energy conversion efficiencies between 0.34% and 3.14% were achieved. The best performance was achieved from AnE-PV ab showing both stacking ability and highest π−π-stacking distance of 0.386 nm as compared to 0.380 nm for the others. Poorer performance resulted from polymers with no inclination to stack, AnE-PV ba, - bb, although they exhibited the higher charge carrier mobilities. Hole mobilities range from 1.5 × 10 −5 cm 2 /V.s ( AnE-PV ad ) to 4.5 × 10 −4 cm 2 /V.s ( AnE-PV ba ). An increase of the open circuit voltage from ∼650 mV to ∼900 mV is observed with decreasing side chain density. In case of the AnE-PV cc:PCBM (1:1) blend a 2-fold increase in solar cell efficiency (from 1% to 2%) was obtained when the active layer was spin cast from a 1:1 mixture of chloroform:chlorobenzene instead of using chlorobenzene.