|Lang, A.S.; Muth, M.A.; Heinrich, C.D.; Carrasco-Orozco, M.; Thelakkat, M.: Pendant perylene polymers with high electron mobility, Journal of Polymer Science Part B: Polymer Physics, 51(20), 1480–1486 (2013) -- DOI: 10.1002/polb.23357|
Four different perylene side-chain semiconductor polymers, synthesized by a combination of “click” chemistry and nitroxide-mediated radical polymerization, are compared in terms of their optical, electrochemical, and charge transport properties. The nature of the solubilizing side chains and the chromophoric π-conjugation system of the pendant perylene moieties are systematically changed. Two poly(perylene bisimide)s with hydrophobic (PPBI 1) and hydrophilic substituents (PPBI 2) are compared with poly(perylene diester benzimidazole) (PPDEB) and poly(perylene diester imide) (PPDEI). Optical properties are investigated by UV/vis and photoluminescence spectroscopy, and charge transport is studied by organic field effect transistor and space-charge-limited current measurements. Cyclic voltammetry is used to estimate highest occupied molecular orbital and lowest unoccupied molecular orbital levels. The extended π-conjugation system of PPDEB leads to a broader absorption in the visible region when compared with PPDEI and the PPBIs. Although absorption properties of PPDEB could be considerably improved by varying the perylene core, the charge carrier mobility could be drastically improved by tuning the substituents. Very high electron mobilities of 1 × 10−2 cm2 V−1 s−1 were achieved for PPBI 2 carrying oligoethyleneglycol substituents.