Synthesis, characterization and photovoltaic properties of platinum-containing poly(aryleneethynylene) polymers with electron-deficient diketopyrrolopyrrole unit

Three new solution-processable Pt(II)-containing poly(aryleneethynylene) polymers based on diketopyrrolopyrrole moiety and their corresponding diplatinum model complexes were synthesized via the Sonogashira-type coupling reaction of the platinum(II) chloride precursor and each of the diethynyl ligands. The photophysical, thermal stability, electrochemical, carrier mobility and photovoltaic properties of these polymers were fully investigated. These polymers exhibit strong absorption bands in the range of 550–750 nm, and fluorescent bands between 650 and 850 nm. One thiophene flanked diketopyrrolopyrrole based polymer with linear n-octyl chains shows a better photovoltaic performance than that made from the branched 2-ethylhexyl analogue.