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Broad Absorption (broad + absorption)
Selected AbstractsCarbon Nanotubes on Polymeric Microcapsules: Free-Standing Structures and Point-Wise Laser OpeningsADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Alexey M. Yashchenok Abstract Single-wall carbon nanotubes modified by anionic polyelectrolyte molecules are embedded into the shells of microcapsules. Carbon nanotubes serve as rigid rods in a softer polymeric capsule, which forms a free-standing shell upon treatment with glutaraldehyde and subsequent drying. The embedded carbon nanotubes exhibit a broad absorption in the UV,near-infrared part of the spectrum, and that allows point-wise activation and opening of the microcapsules by laser. Raman signal analysis shows changes of carbon-nanotube-specific lines after high-power laser irradiation, which is characteristic of the formation of disordered carbonlike structures. These polyelectrolyte/carbon nanotube composite capsules represent a novel light-addressable type of microcontainers. [source] Donor,Acceptor C60 -Containing Polyferrocenylsilanes: Synthesis, Characterization, and Applications in Photodiode Devices,ADVANCED FUNCTIONAL MATERIALS, Issue 3 2008Masato Nanjo Abstract A series of polyferrocenylsilane (PFS) random copolymers containing covalently bound pendant [C60]fullerene groups, the first well-characterized metallopolymers with pendant C60 units, have been prepared and characterized. The fullerene content of the prepared copolymers ranges from 7 to 24% relative to monomer unit. The desired copolymers were synthesized in three steps: metal-catalyzed ring opening polymerization of sila[1]ferrocenophanes was performed to synthesize random copolymers of poly(ferrocenylmethylphenylsilane -co- ferrocenylchloromethylsilane); the resulting random PFSs were then functionalized by reaction with 11-azido-1-undecanol to give PFSs with pendant azide groups; the desired donor,acceptor C60 -containing PFSs were then synthesized by the reaction of the azide group in the side chains with C60 in toluene at 110,°C. The resulting C60 -containing PFSs are air-stable and soluble in aromatic solvents, chloroform, or THF. The UV-vis spectra of these materials show broad absorption up to 800 nm. Thin films of these materials were examined as the active layer in rare examples of all solid-state sandwich-type diode devices based on ferrocene-fullerene dyads. The devices exhibit photoconducting and photovoltaic responses, with an open circuit potential of ca. 0.3 V under white light illumination. [source] Synthesis and applications of low-bandgap conjugated polymers containing phenothiazine donor and various benzodiazole acceptors for polymer solar cellsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 21 2010Harihara Padhy Abstract A series of soluble donor-acceptor conjugated polymers comprising of phenothiazine donor and various benzodiazole acceptors (i.e., benzothiadiazole, benzoselenodiazole, and benzoxadiazole) sandwiched between hexyl-thiophene linkers were designed, synthesized, and used for the fabrication of polymer solar cells (PSC). The effects of the benzodiazole acceptors on the thermal, optical, electrochemical, and photovoltaic properties of these low-bandgap (LBG) polymers were investigated. These LBG polymers possessed large molecular weight (Mn) in the range of 3.85,5.13 × 104 with high thermal decomposition temperatures, which demonstrated broad absorption in the region of 300,750 nm with optical bandgaps of 1.80,1.93 eV. Both the HOMO energy level (,5.38 to ,5.47 eV) and LUMO energy level (,3.47 to ,3.60 eV) of the LBG polymers were within the desirable range of ideal energy level. Under 100 mW/cm2 of AM 1.5 white-light illumination, bulk heterojunction PSC devices containing an active layer of electron donor polymers mixed with electron acceptor [6,6]-phenyl-C61 -butyric acid methyl ester (PC61BM) or [6,6]-phenyl-C71 -butyric acid methyl ester (PC71BM) in different weight ratios were investigated. The best performance of the PSC device was obtained by using polymer PP6DHTBT as an electron donor and PC71BM as an acceptor in the weight ratio of 1:4, and a power conversion efficiency value of 1.20%, an open-circuit voltage (Voc) value of 0.75 V, a short-circuit current (Jsc) value of 4.60 mA/cm2, and a fill factor (FF) value of 35.0% were achieved. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 [source] Low bandgap ,-conjugated copolymers based on fused thiophenes and benzothiadiazole: Synthesis and structure-property relationship studyJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2009Shiming Zhang Abstract A series of low bandgap conjugated polymers consisting of benzothiadiazole alternating with dithienothiophene (DTT) or dithienopyrrole (DTP) unit with or without 3-alkylthiophene bridge have been synthesized. Effect of the fused rings and 3-alkylthiophene bridge on the thermal, optical, electrochemical, charge transport, and photovoltaic properties of these polymers have been investigated. These polymers show broad absorption extending from 300 to 1000 nm with optical bandgaps as low as 1.2 eV; the details of which can be varied either by incorporating 3-alkylthiophene bridge or by replacing DTT with DTP. The LUMO levels (,2.9 to ,3.3 eV) are essentially unaffected by the specific choice of donor moiety, whereas the HOMO levels (,4.6 to ,5.6 eV) are more sensitive to the choice of donor. The DTT and DTP polymers with 3-alkylthiophene bridge were found to exhibit hole mobilities of 8 × 10,5 and 3 × 10,2 cm2 V,1 s,1, respectively, in top-contact organic field-effect transistors. Power conversion efficiencies in the range 0.17,0.43% were obtained under simulated AM 1.5, 100 mW cm,2 irradiation for polymer solar cells using the DTT and DTP-based polymers with 3-alkylthiophene bridge as donor and fullerene derivatives as acceptor. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5498,5508, 2009 [source] | ||||||||||