A5051206276- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Magnetism in coordination complexes
- Electron Spin Resonance Studies
- Photochemistry and Electron Transfer Studies
- Organic Electronics and Photovoltaics
- Conducting polymers and applications
- Lanthanide and Transition Metal Complexes
- Chemical Reactions and Mechanisms
- Molecular Junctions and Nanostructures
- Organic Light-Emitting Diodes Research
- Organic and Molecular Conductors Research
- Advanced Chemical Physics Studies
- Synthesis and Properties of Aromatic Compounds
- Crystallography and molecular interactions
- Luminescence and Fluorescent Materials
- Radical Photochemical Reactions
- Free Radicals and Antioxidants
- Oxidative Organic Chemistry Reactions
- Organometallic Complex Synthesis and Catalysis
- Organic Chemistry Cycloaddition Reactions
- Advanced NMR Techniques and Applications
- Advanced Physical and Chemical Molecular Interactions
- Synthesis and properties of polymers
- Inorganic and Organometallic Chemistry
University of Massachusetts Amherst
2012-2023
Amherst College
2014-2018
University of Massachusetts Lowell
2013
Aalto University
2012
Ball State University
2008
Ruhr University Bochum
2008
Osaka University
2002-2008
Tulane University
2007
Keio University
2007
Universidade de São Paulo
2003-2007
Solar cells fabricated using alkyl ammonium metal halides as light absorbers have the right combination of high power conversion efficiency and ease fabrication to realize inexpensive but efficient thin film solar cells. However, they degrade under prolonged exposure sunlight. Herein, we show that this degradation is quasi-reversible, it can be greatly lessened by simple modifications cell operating conditions. We studied perovskite devices electrochemical impedance spectroscopy (EIS) with...
Coordination of a [Co(hfac)2] moiety (hfac = hexafluoroacetylacetonate) with nitronylnitroxide radical linked to bulky, rigid pyrene (PyrNN) gives helical 1:1 chain complex, in which both oxygen atoms the NO(·) groups are bonded Co(II) ions strong antiferromagnetic exchange. The complex shows single-chain magnet (SCM) behavior frequency-dependent magnetic susceptibility, field-cooled and zero-field-cooled susceptibility divergence high blocking temperature around 14 K (a record among SCMs),...
Two isostructural 1D complexes, [M(hfac)2NaphNN]n [M = Mn(II) (1) or Co(II) (2); NaphNN 1-naphthyl nitronylnitroxide], were synthesized and exhibit very strong antiferromagnetic metal-radical exchange coupling. Compound 2 shows slow magnetic relaxation behavior with a high blocking temperature (TB ≈ 13.2 K) coercive field of 49 kOe at 4.0 K.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSemiempirical study of electron exchange interaction in organic high-spin .pi.-systems. Classifying structural effects magnetic moleculesPaul M. Lahti and Andrew S. IchimuraCite this: J. Org. Chem. 1991, 56, 9, 3030–3042Publication Date (Print):April 1, 1991Publication History Published online1 May 2002Published inissue 1 April 1991https://pubs.acs.org/doi/10.1021/jo00009a020https://doi.org/10.1021/jo00009a020research-articleACS PublicationsRequest...
Chemically stable poly[2-(3,5-di-tert-butyl-4-oxyphenyl)-1,4(p)-phenylenevinylene], poly[4-(3,5-di-tert-butyl-4-oxyphenyl)-1,3(m)-phenylenevinylene], and poly[4-(3,5-di-tert-butyl-4-oxyphenyl)-1,2(o)-phenylenevinylene] were synthesized via the polymerization of 4-bromo-2-(3,5-di-tert-butyl-4-acetoxyphenyl)styrene, 5-bromo-2-(3,5-di-tert-butyl-4-acetoxyphenyl)styrene, 2-bromo-4-(3,5-di-tert-butyl-4-acetoxyphenyl)styrene, respectively, using a palladium catalyst. The o- p-polyradicals, even...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUse of the Pariser-Parr-Pople approximation to obtain practically useful predictions for electronic spectral properties conducting polymersPaul M. Lahti, Jan Obrzut, and Frank E. KaraszCite this: Macromolecules 1987, 20, 8, 2023–2026Publication Date (Print):August 1, 1987Publication History Published online1 May 2002Published inissue 1 August 1987https://pubs.acs.org/doi/10.1021/ma00174a056https://doi.org/10.1021/ma00174a056research-articleACS...
We address here the need for a general strategy to control molecular assembly over multiple length scales. Efficient organic photovoltaics require an active layer comprised of mesoscale interconnected networks nanoscale aggregates semiconductors. demonstrate method, using principles self-assembly and geometric packing, controlled semiconductors at mesoscale. Nanoparticles poly(3-hexylthiophene) (P3HT) or [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) were fabricated with targeted sizes....
We report the processing conditions for fabricating efficient organic solar cells from aqueous dispersions of conjugated polymer nanoparticles.
Cryogenic matrix photolysis of 3,5-dichloro-2,4,6-triazidopyridine, 3-chloro-5-cyano-2,4,6-triazidopyridine, 3,5-dicyano-2,4,6-triazidopyridine, and 3,5-difluoro-2,4,6-triazidopyridine (1−4) gives rise to ESR spectral peaks various triplet mononitrene, quintet dinitrene, septet trinitrene species. The 2,4-dinitrenes derived from 1−2 4 have zero-field splittings (zfs) |D/hc| ∼ 0.22−0.24 cm-1, similar values observed elsewhere for m-phenylene dinitrenes. 3,5-Dicyano-2,4,6-triazidopyridine (3)...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTModels for intramolecular exchange in organic .pi.-conjugated open-shell systems. A comparison of 1,1-ethenediyl and carbonyl linked bis(arylnitrenes)Chris Ling, Masaki Minato, Paul M. Lahti, Hans Van WilligenCite this: J. Am. Chem. Soc. 1992, 114, 25, 9959–9969Publication Date (Print):December 1, 1992Publication History Published online1 May 2002Published inissue 1 December...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTEnergies of non-Kekule molecular states. Calculation by a predictively useful semiempirical methodPaul M. Lahti, Angelo Rossi, and Jerome A. BersonCite this: J. Am. Chem. Soc. 1985, 107, 8, 2273–2280Publication Date (Print):April 1, 1985Publication History Published online1 May 2002Published inissue 1 April 1985https://pubs.acs.org/doi/10.1021/ja00294a011https://doi.org/10.1021/ja00294a011research-articleACS PublicationsRequest reuse...
We report the design, synthesis, and characterization of a series thieno[3,4-b]thiophene acceptor blocks with octyl (T8), phenyl (TP), perfluorooctyl (TF8), perfluorophenyl (TFP) side groups. Their subsequent copolymerization dithienylbenzodithiophene by direct arylation polymerization afforded novel low bandgap poly(thienothiophene-alt-dithienylbenzodithiophene) (PTB) polymers. The strongly electron withdrawing TF8 TFP groups were shown to significantly lower both EHOMO ELUMO levels gave...
Three fluorine-containing polymers, poly(2-fluoro-1,4-phenylene vinylene), poly(2,5-difluoro-1,4-phenylene and poly(2[5]-(n-hexyloxy)-5[2]-fluoro-1,4-phenylene vinylene) (1−3, respectively) have been synthesized by the soluble precursor method were used to fabricate light emitting diode (LED) devices. Monosubstituted 1 yielded an electroluminescent emission peaking at 560 nm (green-yellow); polymers 2 3 emitted in 600−610 region (red). The result for represents a blue shift relative from...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAb initio calculations on m-quinone. The ground state is a tripletRaymond C. Fort Jr., Stephen J. Getty, David A. Hrovat, Paul M. Lahti, and Weston Thatcher BordenCite this: Am. Chem. Soc. 1992, 114, 19, 7549–7552Publication Date (Print):September 1, 1992Publication History Published online1 May 2002Published inissue 1 September 1992https://doi.org/10.1021/ja00045a031RIGHTS & PERMISSIONSArticle Views189Altmetric-Citations55LEARN ABOUT THESE...
5-(3-(N-tert-Butyl-N-aminoxyl)phenyl)pyrimidine (RL = 3NITPhPyrim) forms isostructural cyclic M2(RL)2 dimers with M(hfac)2 (M Mn, Co, Cu; hfac hexafluoroacetylacetonate). Mn2(hfac)4(RL)2 exhibits strong antiferromagnetic Mn-RL exchange, weak ferromagnetic exchange (0.7 cm(-1)) between units that is consistent a spin polarization mechanism. The magnetic moment of Co2(hfac)4(RL)2 at higher temperatures strongly within the Co-NIT and tends toward zero below 50 K lower fields. Cu2(hfac)4(RL)2...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPolymerization of .alpha.,.alpha.'-bis(dialkylsulfonio)-p-xylene dihalides via p-xylylene intermediates: evidence for a nonradical mechanismPaul M. Lahti, David A. Modarelli, Frank R. Denton, Robert W. Lenz, and E. KaraszCite this: J. Am. Chem. Soc. 1988, 110, 21, 7258–7259Publication Date (Print):October 1, 1988Publication History Published online1 May 2002Published inissue 1 October 1988https://doi.org/10.1021/ja00229a074RIGHTS &...
Charge transport through a semiconducting nanoparticle assembly is demonstrated. The hole mobility of low and high molecular weight regioreglular poly(3-hexylthiophene) (P3HT) nanoparticles on the order 2 × 10−4 to 5 cm2 V−1 s−1, which comparable drop-cast thin films pristine P3HT. Various methods are employed understand nature importance packing.
The synthesis, structure and magnetic properties of lanthanide-biradical complexes are reported.
A series of new PPV-based alternating copolymers containing conjugated and nonconjugated blocks have been synthesized with the objective raising glass transition temperature (Tg) relative to structures previously obtained. The higher Tg was achieved by inserting a more rigid unit in spacer soft block. effects molecular architecture chromophore substituents on optical redox properties polymers were investigated. UV−vis absorption emission solid state range 360−415 455−533 nm, respectively....
The "push−pull" electronically substituted systems poly(2[5]-chloro-5[2]-(n-hexyloxy)-1,4-phenylenevinylene) and poly(2[5]-bromo-5[2]-(n-hexyloxy)-1,4-phenylenevinylene)1 2, respectivelywere synthesized by a modified soluble precursor route. Thermal elimination of polyether precursors to 1 2 yields the final conjugated polymers as free-standing, flexible red films. may be film-cast from methanol make light emitting diode (LED) devices which have emission in 620 nm region. ease synthesis...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAb initio computational study of methano- and ethano-bridged derivatives oxyallylAndrew S. Ichimura, Paul M. Lahti, Albert R. MatlinCite this: J. Am. Chem. Soc. 1990, 112, 8, 2868–2875Publication Date (Print):April 1, 1990Publication History Published online1 May 2002Published inissue 1 April 1990https://pubs.acs.org/doi/10.1021/ja00164a004https://doi.org/10.1021/ja00164a004research-articleACS PublicationsRequest reuse permissionsArticle...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of two bis-m-quinomethanes. An experimental study connectivity effects on the equal-parity criterion for low-spin ground states in alternant non-Kekule moleculesDavid E. Seeger, Paul M. Lahti, Angelo R. Rossi, and Jerome A. BersonCite this: J. Am. Chem. Soc. 1986, 108, 6, 1251–1265Publication Date (Print):March 1, 1986Publication History Published online1 May 2002Published inissue 1 March...
Abstract The photoluminescence (PL) and electroluminescence (EL) of four 2,7‐bis(phenylethenyl)fluorenes (OFPVs) two 2,7‐diphenylfluorenes (OFPhs) are compared to evaluate effects nonconjugating peripheral substitution conjugation length on their EL emissions. OFPVs exhibit very similar PL spectra with 460–480 nm emission maxima but show large variation in the organic light‐emitting diode (OLED) efficacy: from a material that does not give persistent test OLEDs (9,9‐diheptyl fluorene ring)...