Inhaltszusammenfassung

New 4-fold alkoxy-substituted poly(p-phenylene-ethynylen(-,)-alt-poly(p-phenylene-vinylene) polymers (PPE-PPV) have been synthesized in order to elucidate the previously observed effect of side chains on the thin film properties (i.e., color variation) of PPE-PPVs. The length of the side chains attached to the PPE segments, CnH2n+1, has been varied from n = 12 to 19. The side chains attached to the PPV segments have been kept fixed to C8H17. Polymers with n < 16 are yellow in color, wh...New 4-fold alkoxy-substituted poly(p-phenylene-ethynylen(-,)-alt-poly(p-phenylene-vinylene) polymers (PPE-PPV) have been synthesized in order to elucidate the previously observed effect of side chains on the thin film properties (i.e., color variation) of PPE-PPVs. The length of the side chains attached to the PPE segments, CnH2n+1, has been varied from n = 12 to 19. The side chains attached to the PPV segments have been kept fixed to C8H17. Polymers with n < 16 are yellow in color, whereas those with n >= 16 are orange. Differential scanning calorimetry and nanoindentation analyses reveal side chain crystallization above room temperature in samples with longer side chains (n >= 16). Reorganization of the longer side chains attached to the PPE units seems to support stronger pi-pi overlap between the chain backbones. The red shift for n >= 16 was confirmed by photoluminescence (PL) and electroluminescence (EL) spectra obtained for inkjet printed and spin-coated thin films. However, the obtained orange-red EL emission colors are unstable upon increase of the applied voltage. A blue shift of up to 100 nm was observed. All the polymers exhibited very high relative and absolute PL quantum yields in solution (similar to 70%). Their solid-state absolute PL quantum yield was found to be between 10 and 20%. Polymeric light emitting diodes (PLED) with the following structure ITO//PEDOT:PSS//Pn/8//Ca//Ag were fabricated. The devices were fully characterized and showed low turn-on voltages. » weiterlesen» einklappen

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DDC Sachgruppe:
Chemie