Near-infrared emissive BODIPY polymeric and copolymeric dyes

Novel near-Infrared emissive BODIPY polymeric dyes (polymers A and B) were prepared by Sonogashira cross-coupling reaction of 2,6-diiodo BODIPY dyes bearing one and two styryl groups at 3,5 positions (5, 6) with 2,6-diethynyl BODIPY dye, respectively. These polymeric dyes (A and B) display absorption maxima at 697 and 738 nm, and emission maxima at 715 and 760 nm, respectively. These polymeric dyes exhibit significant red shifts in absorption and emission maxima due to their extended π-conjugation systems compared with their BODIPY monomeric dyes. The thin films of polymers A and B display further red shift with emission maxima 764 and 810 nm, respectively. Near-infrared BODIPY copolymeric dye (C) was prepared by Sonogashira polymerization of 2,6-diiodo BODIPY dye bearing two styryl groups with 2,5-diethynyl-3-decylthiophene. For comparison in optical properties, deep-red and red emissive BODIPY copolymeric dyes (D and E) were prepared by Sonogashira polymerization of 2,6-diiodo BODIPY dye bearing monostyryl group and 2,6-diiodo BODIPY dye with 2,5-diethynyl-3-decylthiothene, respectively. These polymers display their absorption maxima at 649 nm and 634 nm, and emission maxima at 694 nm and 669 nm, respectively. All the polymers displayed good thermal stability and solubility in dichloromethane, and their lifetimes ranged from 0.7 to 3.4 ns. © 2010 Elsevier Ltd

Deep-red emissive conjugated poly(2,6-BODIPY-ethynylene)s bearing alkyl side chains

Novel deep-red emissive poly(2,6-BODIPY-ethynylene)s bearing dodecyl side chains (polymers A, B, and C) have been prepared by palladium-catalyzed Sonogashira polymerization of 2,6-diiodo-functionalized BODIPY monomers with 2,6-diethynyl-functionalized BODIPY monomers. These polymers emit in the deep-red region with emission maxima at up to 690 nm, and exhibit significant red shifts (up to 166 and 179 nm) of both absorption and emission maxima compared with their parent BODIPY dyes due to significant extension of π-conjugation. These polymers possess good thermal stability with decomposition temperature between 270 and 360°C. The polymers exhibit a little larger Stokes shifts and shorter lifetime than their corresponding BODIPY dyes. The solid state thin films of polymers A, B, and C emit in near-infrared region between 723 and 743 nm, and show significantly red shifts (up to 57 nm) in absorption and emission maxima relative to their polymer solution

Electromechanical properties of self-assembled monolayers of tetrathiafulvalene derivatives studied by conducting probe atomic force microscopy

The electrical conduction of metal-molecule-metal junctions formed between Au-supported selfassembled monolayers (SAMs) of symmetric tetrathiafulvalene (TTF) derivatives and a Pt-coated atomic force microscope (AFM) tip has been measured under different compression forces using conducting probe AFM. The TTFs are linked to the metal through double metal-thiol linkers on both sides of the molecule. The TTF junctions exhibit remarkably high electrical conduction with estimated single molecule resistance of 14.7 ± 3.4 GΩ, corresponding to the molecular resistivity of 390 Ω·cm. A single molecule resistance of a comparable length 1-decanethiol molecule is estimated to be several orders of magnitude higher with the value of 950 ± 22 GΩ. The TTF junction resistance displayed a unique nonlinear dependence with the compression force. The dependence is attributed to the change in the intermolecular electronic coupling between the TTF molecules. © 2010 American Chemical Society

Bodipy-backboned polymers as electron donor in bulk heterojunction solar cells

Bodipy-based polymers, which possess a high absorption coefficient with a bandgap of similar to 1.6 eV, have been used as electron donor in solution-processed bulk heterojunction (BHJ) solar cells containing PCBM as acceptor. A power conversion efficiency (PCE) of similar to 2% has been achieved with V(oc) of similar to 0.8 eV and J(sc) of similar to 4.8 mA cm(-2)

Synthesis and optical properties of red and deep-red emissive polymeric and copolymeric BODIPY dyes

Deep-red emissive polymeric BODIPY dyes (polymers A and B), poly(2,6-BODIPY-ethynylene)s, were prepared by palladium-catalyzed Sonogashira polymerization of 2,6-diiodo-functionalized BODIPY monomers with 2,6-diethynyl-functionalized BODIPY monomers. Poly(2,6-BODIPY-ethynylene)s emit in the deep-red region with emission spectral maxima at around 680 nm and exhibit significant red shifts (up to 163 and 172 nm) of both absorption and emission maxima compared with their initial BODIPY dyes due to significant extension of π-conjugation. Red emissive copolymeric BODIPY dyes (polymers C, D, and E) were also prepared by palladium-catalyzed Sonogashira polymerization of a diethynyl-functionalized BODIPY monomer with 9,9-bis(6′-(hexylthio)hexyl)-2,7-diiodo-9H-fluorene, 1,4-diiodo-2,5-didecyloxybenzene, and 2,5-diiodo-3-decylthiophene, respectively. Incorporation of different band gap monomer units into poly(2,6-BODIPY-ethynylene)s resulted in copolymers with a range of emission wavelengths from 641 to 664 nm. The fluorescence lifetimes of these polymers (polymers A−D) are from 2.8 to 3.8 ns except the copolymer with thiophene moieties (polymer E), which displays a much shorter lifetime of 0.23 ns with low fluorescence quantum yield due to efficient intersystem crossing induced by the heavy atom effect of sulfur