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Pickett A, Torkkeli M, Mukhopadhyay T, Puttaraju B, Laudari A, Lauritzen AE, Bikondoa O, Kjelstrup-Hansen J, Knaapila M, Patil S, Guha S. Correlating Charge Transport with Structure in Deconstructed Diketopyrrolopyrrole Oligomers: A Case Study of a Monomer in Field-Effect Transistors. ACS APPLIED MATERIALS & INTERFACES 2018; 10:19844-19852. [PMID: 29771117 DOI: 10.1021/acsami.8b04711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Copolymers based on diketopyrrolopyrrole (DPP) cores have attracted a lot of attention because of their high p-type as well as n-type carrier mobilities in organic field-effect transistors (FETs) and high power conversion efficiencies in solar cell structures. We report the structural and charge transport properties of n-dialkyl side-chain-substituted thiophene DPP end-capped with a phenyl group (Ph-TDPP-Ph) monomer in FETs which were fabricated by vacuum deposition and solvent coating. Grazing-incidence X-ray diffraction (GIXRD) from bottom-gate, bottom-contact FET architectures was measured with and without biasing. Ph-TDPP-Ph reveals a polymorphic structure with π-conjugated stacking direction oriented in-plane. The unit cell comprises either one monomer with a = 20.89 Å, b = 13.02 Å, c = 5.85 Å, α = 101.4°, β = 90.6°, and γ = 94.7° for one phase (TR1) or two monomers with a = 24.92 Å, b = 25.59 Å, c = 5.42 Å, α = 80.3°, β = 83.5°, and γ = 111.8° for the second phase (TR2). The TR2 phase thus signals a shift from a coplanar to herringbone orientation of the molecules. The device performance is sensitive to the ratio of the two triclinic phases found in the film. Some of the best FET performances with p-type carrier mobilities of 0.1 cm2/V s and an on/off ratio of 106 are for films that comprise mainly the TR1 phase. GIXRD from in operando FETs demonstrates the crystalline stability of Ph-TDPP-Ph.
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Affiliation(s)
- Alec Pickett
- Department of Physics and Astronomy , University of Missouri , Columbia , Missouri 65211 , United States
| | - Mika Torkkeli
- Department of Physics , Technical University of Denmark , 2800 Kongens Lyngby , Denmark
| | - Tushita Mukhopadhyay
- Solid State and Structural Chemistry Unit , Indian Institute of Science , Bangalore 560012 , India
| | - Boregowda Puttaraju
- Solid State and Structural Chemistry Unit , Indian Institute of Science , Bangalore 560012 , India
| | - Amrit Laudari
- Department of Physics and Astronomy , University of Missouri , Columbia , Missouri 65211 , United States
| | - Andreas E Lauritzen
- Department of Physics , Technical University of Denmark , 2800 Kongens Lyngby , Denmark
- Department of Physics , University of Oxford , OX13PU Oxford , U.K
| | - Oier Bikondoa
- Department of Physics , University of Warwick , Gibbet Hill Road , CV4 7AL Coventry , U.K
| | - Jakob Kjelstrup-Hansen
- NanoSYD, Mads Clausen Institute , University of Southern Denmark , 6400 Sønderborg , Denmark
| | - Matti Knaapila
- Department of Physics , Technical University of Denmark , 2800 Kongens Lyngby , Denmark
| | - Satish Patil
- Solid State and Structural Chemistry Unit , Indian Institute of Science , Bangalore 560012 , India
| | - Suchismita Guha
- Department of Physics and Astronomy , University of Missouri , Columbia , Missouri 65211 , United States
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Kogikoski S, Khanra S, Alves WA, Guha S. SERS active self-assembled diphenylalanine micro/nanostructures: A combined experimental and theoretical investigation. J Chem Phys 2018; 147:084703. [PMID: 28863534 DOI: 10.1063/1.4990828] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Enhancing Raman signatures of molecules by self-assembled metal nanoparticles, nanolithography patterning, or by designing plasmonic nanostructures is widely used for detection of low abundance biological systems. Self-assembled peptide nanostructures provide a natural template for tethering Au and Ag nanoparticles due to its fractal surface. Here, we show the use of L,L-diphenylalanine micro-nanostructures (FF-MNSs) for the organization of Ag and Au nanoparticles (Nps) and its potential as surface-enhanced Raman scattering (SERS)-active substrates. The FF-MNSs undergo an irreversible phase transition from hexagonally packed (hex) micro-nanotubes to an orthorhombic (ort) structure at ∼150 °C. The metal Nps form chains on hex FF-MNSs as inferred from transmission electron microscopy images and a uniform non-aggregated distribution in the ort phase. The high luminescence from the ort FF-MNS phase precludes SERS measurements with AgNps. The calculated Raman spectra using density-functional theory shows a higher intensity from rhodamine 6G (R6G) molecule in the presence of an Ag atom bound to ort FF compared with hex FF. The SERS spectra obtained from R6G bound to FF-MNSs with AuNps clearly show a higher enhancement for the ort phase compared with hex FF, corroborating our theoretical calculations. Our results indicate that FF-MNSs both in the hex and ort phases can be used as substrates for the SERS analysis with different metal nanoparticles, opening up a novel class of optically active bio-based substrates.
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Affiliation(s)
- Sergio Kogikoski
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, SP, Brazil
| | - Soma Khanra
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, USA
| | - Wendel A Alves
- Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, SP, Brazil
| | - Suchismita Guha
- Department of Physics and Astronomy, University of Missouri, Columbia, Missouri 65211, USA
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Ruiz C, Pandey UK, Termine R, García-Frutos EM, López-Espejo G, Ortiz RP, Huang W, Marks TJ, Facchetti A, Ruiz Delgado MC, Golemme A, Gómez-Lor B. Mobility versus Alignment of a Semiconducting π-Extended Discotic Liquid-Crystalline Triindole. ACS APPLIED MATERIALS & INTERFACES 2016; 8:26964-26971. [PMID: 27643623 DOI: 10.1021/acsami.6b06241] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The p-type semiconducting properties of a triphenylene-fused triindole mesogen, have been studied by applying two complementary methods which have different alignment requirements. The attachment of only three flexible alkyl chains to the nitrogen atoms of this π-extended core is sufficient to induce columnar mesomorphism. High hole mobility values (0.65 cm2 V-1 s-1) have been estimated by space-charge limited current (SCLC) measurements in a diode-like structure which are easily prepared from the melt, rendering this material a good candidate for OPVs and OLEDs devices. The mobility predicted theoretically via a hole-hopping mechanism is in very good agreement with the experimental values determined at the SCLC regime. On the other hand the hole mobility determined on solution processed thin film transistors (OFETs) is significantly lower, which can be rationalized by the high tendency of these large molecules to align on surfaces with their extended π-conjugated core parallel to the substrate as demonstrated by SERS. Despite the differences obtained with the two methods, the acceptable performance found on OFETs fabricated by simple drop-casting processing of such an enlarged aromatic core is remarkable and suggests facile hopping between neighboring molecular columns owing to the large conducting/isolating ratio found in this discotic compound.
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Affiliation(s)
- Constanza Ruiz
- Instituto de Ciencia de Materiales de Madrid, CSIC , Cantoblanco, 28049, Madrid, Spain
- Department of Chemistry and the Materials Research Center, the Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Upendra K Pandey
- LASCAMM CR-INSTM, CNR-NANOTEC Lab LiCryL, Dipartimento di Fisica, Università della Calabria , 87036 Rende, Italy
- Interdisciplinary Centre for Energy Research, Indian Institute of Science , Bangalore, 560012, India
| | - Roberto Termine
- LASCAMM CR-INSTM, CNR-NANOTEC Lab LiCryL, Dipartimento di Fisica, Università della Calabria , 87036 Rende, Italy
| | - Eva M García-Frutos
- Instituto de Ciencia de Materiales de Madrid, CSIC , Cantoblanco, 28049, Madrid, Spain
| | - Guzmán López-Espejo
- Department of Physical Chemistry, University of Málaga , 29071, Málaga, Spain
| | - Rocío Ponce Ortiz
- Department of Physical Chemistry, University of Málaga , 29071, Málaga, Spain
| | - Wei Huang
- Department of Chemistry and the Materials Research Center, the Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Tobin J Marks
- Department of Chemistry and the Materials Research Center, the Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Antonio Facchetti
- Department of Chemistry and the Materials Research Center, the Argonne-Northwestern Solar Energy Research Center, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | | | - Attilio Golemme
- LASCAMM CR-INSTM, CNR-NANOTEC Lab LiCryL, Dipartimento di Fisica, Università della Calabria , 87036 Rende, Italy
| | - Berta Gómez-Lor
- Instituto de Ciencia de Materiales de Madrid, CSIC , Cantoblanco, 28049, Madrid, Spain
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Knaapila M, Guha S. Blue emitting organic semiconductors under high pressure: status and outlook. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:066601. [PMID: 27116082 DOI: 10.1088/0034-4885/79/6/066601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
This review describes essential optical and emerging structural experiments that use high GPa range hydrostatic pressure to probe physical phenomena in blue-emitting organic semiconductors including π-conjugated polyfluorene and related compounds. The work emphasizes molecular structure and intermolecular self-organization that typically determine transport and optical emission in π-conjugated oligomers and polymers. In this context, hydrostatic pressure through diamond anvil cells has proven to be an elegant tool to control structure and interactions without chemical intervention. This has been highlighted by high pressure optical spectroscopy whilst analogous x-ray diffraction experiments remain less frequent. By focusing on a class of blue-emitting π-conjugated polymers, polyfluorenes, this article reviews optical spectroscopic studies under hydrostatic pressure, addressing the impact of molecular and intermolecular interactions on optical excitations, electron-phonon interaction, and changes in backbone conformations. This picture is connected to the optical high pressure studies of other π-conjugated systems and emerging x-ray scattering experiments from polyfluorenes which provides a structure-property map of pressure-driven intra- and interchain interactions. Key obstacles to obtain further advances are identified and experimental methods to resolve them are suggested.
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Affiliation(s)
- Matti Knaapila
- Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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Chen J, Xiao HJ, Qi T, Chen DL, Long HM, Liu SH. Rare earths exposure and male infertility: the injury mechanism study of rare earths on male mice and human sperm. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2015; 22:2076-2086. [PMID: 25167826 DOI: 10.1007/s11356-014-3499-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 08/20/2014] [Indexed: 06/03/2023]
Abstract
The weight; testis/body coefficient; levels of LDH, SDH, SODH, G-6PD, and testosterone; cell cycle; and cell apoptosis of the male mice were influenced after being treated with 200 mg/[kg/day] of rare earths suspension for 3 weeks. The "Raman fingerprints" of the human sperm DNA exposed to 0.040 mg/ml CeCl3 were very different from those of the untreated; the Raman bands at 789 cm(-1) (backbone phosphodiester), PO4 backbone at 1,094 cm(-1), methylene deformation mode at 1,221 cm(-1), methylene deformation mode at 1,485 cm(-1), and amide II at 1,612 cm(-1), of which intensities and shifts were changed, might be the diagnostic biomarkers or potential therapeutic targets. The injury mechanism might be that the rare earths influence the oxidative stress and blood testosterone barrier, tangle the big biomolecule concurrently, which might cause the testicular cells and vascular system disorder and/or dysfunction, and at the same time change the physical and chemical properties of the sperm directly.
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Affiliation(s)
- Jun Chen
- Department of Infertility and Sexual Medicine, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, 510631, China
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