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Walsh CP, Malizia JP, Sutton SC, Papanikolas JM, Cahoon JF. Monolayer-like Exciton Recombination Dynamics of Multilayer MoSe 2 Observed by Pump-Probe Microscopy. Nano Lett 2024; 24:1431-1438. [PMID: 38252694 DOI: 10.1021/acs.nanolett.3c04754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Transition metal dichalcogenides (TMDCs) have garnered considerable interest over the past decade as a class of semiconducting layered materials. Most studies on the carrier dynamics in these materials have focused on the monolayer due to its direct bandgap, strong photoluminescence, and strongly bound excitons. However, a comparative understanding of the carrier dynamics in multilayer (e.g., >10 layers) flakes is still absent. Recent computational studies have suggested that excitons in bulk TMDCs are confined to individual layers, leading to room-temperature stable exciton populations. Using this new context, we explore the carrier dynamics in MoSe2 flakes that are between ∼16 and ∼125 layers thick. We assign the kinetics to exciton-exciton annihilation (EEA) and Shockley-Read-Hall recombination of free carriers. Interestingly, the average observed EEA rate constant (0.003 cm2/s) is nearly independent of flake thickness and 2 orders of magnitude smaller than that of an unencapsulated monolayer (0.33 cm2/s) but very similar to values observed in encapsulated monolayers. Thus, we posit that strong intralayer interactions minimize the effect of layer thickness on recombination dynamics, causing the multilayer to behave like the monolayer and exhibit an apparent EEA rate intrinsic to MoSe2.
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Affiliation(s)
- Cullen P Walsh
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Jason P Malizia
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Sarah C Sutton
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - John M Papanikolas
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - James F Cahoon
- Department of Chemistry, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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2
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Cheshire TP, Boodry J, Kober EA, Brennaman MK, Giokas PG, Zigler DF, Moran AM, Papanikolas JM, Meyer GJ, Meyer TJ, Houle FA. A quantitative model of charge injection by ruthenium chromophores connecting femtosecond to continuous irradiance conditions. J Chem Phys 2022; 157:244703. [PMID: 36586990 DOI: 10.1063/5.0127852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A kinetic framework for the ultrafast photophysics of tris(2,2-bipyridine)ruthenium(II) phosphonated and methyl-phosphonated derivatives is used as a basis for modeling charge injection by ruthenium dyes into a semiconductor substrate. By including the effects of light scattering, dye diffusion, and adsorption kinetics during sample preparation and the optical response of oxidized dyes, quantitative agreement with multiple transient absorption datasets is achieved on timescales spanning femtoseconds to nanoseconds. In particular, quantitative agreement with important spectroscopic handles-the decay of an excited state absorption signal component associated with charge injection in the UV region of the spectrum and the dynamical redshift of a ∼500 nm isosbestic point-validates our kinetic model. Pseudo-first-order rate coefficients for charge injection are estimated in this work, with an order of magnitude ranging from 1011 to 1012 s-1. The model makes the minimalist assumption that all excited states of a particular dye have the same charge injection coefficient, an assumption that would benefit from additional theoretical and experimental exploration. We have adapted this kinetic model to predict charge injection under continuous solar irradiation and find that as many as 68 electron transfer events per dye per second take place, significantly more than prior estimates in the literature.
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Affiliation(s)
- Thomas P Cheshire
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Jéa Boodry
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Erin A Kober
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - M Kyle Brennaman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Paul G Giokas
- Coherent Inc., 5100 Patrick Henry Dr., Santa Clara, California 95054, USA
| | - David F Zigler
- Chemistry & Biochemistry Department, California Polytechnic State University, San Luis Obispo, California 93407, USA
| | - Andrew M Moran
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Gerald J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Thomas J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Frances A Houle
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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3
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Niu F, Wang D, Williams LJ, Nayak A, Li F, Chen X, Troian-Gautier L, Huang Q, Liu Y, Brennaman MK, Papanikolas JM, Guo L, Shen S, Meyer TJ. A Semiconductor-Mediator-Catalyst Artificial Photosynthetic System for Photoelectrochemical Water Oxidation. Chemistry 2022; 28:e202102630. [PMID: 35113460 DOI: 10.1002/chem.202102630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Indexed: 11/09/2022]
Abstract
In fabricating an artificial photosynthesis (AP) electrode for water oxidation, we have devised a semiconductor-mediator-catalyst structure that mimics photosystem II (PSII). It is based on a surface layer of vertically grown nanorods of Fe2 O3 on fluorine doped tin oxide (FTO) electrodes with a carbazole mediator base and a Ru(II) carbene complex on a nanolayer of TiO2 as a water oxidation co-catalyst. The resulting hybrid assembly, FTO|Fe2 O3 |-carbazole|TiO2 |-Ru(carbene), demonstrates an enhanced photoelectrochemical (PEC) water oxidation performance compared to an electrode without the added carbaozle base with an increase in photocurrent density of 2.2-fold at 0.95 V vs. NHE and a negatively shifted onset potential of 500 mV. The enhanced PEC performance is attributable to carbazole mediator accelerated interfacial hole transfer from Fe2 O3 to the Ru(II) carbene co-catalyst, with an improved effective surface area for the water oxidation reaction and reduced charge transfer resistance.
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Affiliation(s)
- Fujun Niu
- International Research Center for Renewable Energy (IRCRE) State Key Laboratory of Multiphase Flow in Power Engineering (MFPE), Xi'an Jiaotong University (XJTU), 28 West Xianning Road, Xi'an, Shaanxi, 710049, P. R. China.,Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States
| | - Degao Wang
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States.,Engineering Laboratory of Advanced Energy Materials Ningbo Institute of Industrial Technology, Chinese Academy of Sciences, Ningbo, Zhejiang, 315201, P. R. China
| | - Lenzi J Williams
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States
| | - Animesh Nayak
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States
| | - Fei Li
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States
| | - Xiangyan Chen
- International Research Center for Renewable Energy (IRCRE) State Key Laboratory of Multiphase Flow in Power Engineering (MFPE), Xi'an Jiaotong University (XJTU), 28 West Xianning Road, Xi'an, Shaanxi, 710049, P. R. China
| | - Ludovic Troian-Gautier
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States
| | - Qing Huang
- Engineering Laboratory of Advanced Energy Materials Ningbo Institute of Industrial Technology, Chinese Academy of Sciences, Ningbo, Zhejiang, 315201, P. R. China
| | - Yanming Liu
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States
| | - M Kyle Brennaman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States
| | - Liejin Guo
- International Research Center for Renewable Energy (IRCRE) State Key Laboratory of Multiphase Flow in Power Engineering (MFPE), Xi'an Jiaotong University (XJTU), 28 West Xianning Road, Xi'an, Shaanxi, 710049, P. R. China
| | - Shaohua Shen
- International Research Center for Renewable Energy (IRCRE) State Key Laboratory of Multiphase Flow in Power Engineering (MFPE), Xi'an Jiaotong University (XJTU), 28 West Xianning Road, Xi'an, Shaanxi, 710049, P. R. China
| | - Thomas J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States
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4
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Rader Bowers LM, Puodziukynaite E, Wang L, Morseth ZA, Schanze KS, Reynolds JR, Papanikolas JM. It Is Good to Be Flexible: Energy Transport Facilitated by Conformational Fluctuations in Light-Harvesting Polymers. J Phys Chem B 2021; 125:5885-5896. [PMID: 34043354 DOI: 10.1021/acs.jpcb.1c00368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigate the mechanism of energy transfer between ruthenium(II) (Ru) and osmium(II) (Os) polypyridyl complexes affixed to a polyfluorene backbone (PF-RuOs) using a combination of time-resolved emission spectroscopy and coarse-grained molecular dynamics (CG MD). Photoexcitation of a Ru chromophore initiates Dexter-style energy hopping along isoenergetic complexes followed by sensitization of a lower-energy Os trap. While we can determine the total energy transfer rate within an ensemble of solvated PF-RuOs from time-dependent Os* emission spectra, heterogeneity of the system and inherent polymer flexibility give rise to highly multiexponential kinetics. We developed a three-part computational kinetic model to supplement our spectroscopic results: (1) CG MD model of PF-RuOs that simulates molecular motions out to 700 ns, (2) energy transfer kinetic simulations in CG MD PF-RuOs that produce time-resolved Ru and Os excited-state populations, and (3) computational experiments that interrogate the mechanisms by which motion aids energy transfer. Good agreement between simulated and experimental emission transients reveals that our kinetic model accurately simulates the molecular motion of PF-RuOs during energy transfer. Simulated results indicate that pendant flexibility allows 81% of the excited state to sensitize an Os trap compared to a 48% occupation when we treat pendants statically. Our computational experiments show how static pendants are only able to engage in local energy transfer. The excited state equilibrates across a domain of complexes proximal to the initial excitation and becomes trapped within that unique, frozen locality. Side-chain flexibility enables pendants to swing in and out of the original domain spreading the excited state out to ±30 pendant complexes away from the initial excitation.
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Affiliation(s)
- Leah M Rader Bowers
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Egle Puodziukynaite
- Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States, United States.,School of Chemistry and Biochemistry, School of Materials Science and Engineering, Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Li Wang
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Zachary A Morseth
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Kirk S Schanze
- Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, United States, United States
| | - John R Reynolds
- School of Chemistry and Biochemistry, School of Materials Science and Engineering, Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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5
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Cheshire TP, Brennaman MK, Giokas PG, Zigler DF, Moran AM, Papanikolas JM, Meyer GJ, Meyer TJ, Houle FA. Ultrafast Relaxations in Ruthenium Polypyridyl Chromophores Determined by Stochastic Kinetics Simulations. J Phys Chem B 2020; 124:5971-5985. [DOI: 10.1021/acs.jpcb.0c03110] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Thomas P. Cheshire
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - M. Kyle Brennaman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Paul G. Giokas
- Coherent Inc., Santa Clara, California 95054, United States
| | - David F. Zigler
- Chemistry & Biochemistry Department, California Polytechnic State University, San Luis Obispo, California 93407, United States
| | - Andrew M. Moran
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - John M. Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Gerald J. Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Thomas J. Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Frances A. Houle
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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6
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Han Y, Dillon RJ, Flynn CJ, Rountree ES, Alibabaei L, Cahoon JF, Papanikolas JM, Dempsey JL. Interfacial electron transfer yields in dye-sensitized NiO photocathodes correlated to excited-state dipole orientation of ruthenium chromophores. CAN J CHEM 2018. [DOI: 10.1139/cjc-2017-0359] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Interface dynamics of nanocrystalline NiO thin films sensitized with two ruthenium polypyridyl chromophores have been investigated to examine the influence that excited-state dipole orientation and the position of the bipyridine radical formed in the charge-separated state have on interfacial electron transfer yields. In ultrafast transient absorption experiments, the charge separated state is observed on the nanosecond timescale for the trifluoromethyl-substituted chromophore, [Ru(flpy)2(dcb)]2+ (flpy = 4,4′-bis(trifluoromethyl)-2,2′-bipyridine, dcb = 4,4′-dicarboxy-2,2′-bipyridine), but not for [Ru(bpy)2(dcb)]2+ (bpy = 2,2′-bipyridine). Differences are attributed to the positioning of the bipyridine radical formed in the charge separated state; for [Ru(flpy)2(dcb)]2+, the electron is localized on the flpy ligand distal to the surface, whereas for [Ru(bpy)2(dcb)]2+, the electron is localized on the dcb ligand, proximal to the NiO surface. Enhanced photovoltaic performance is observed for dye-sensitized solar cell devices prepared with [Ru(flpy)2(dcb)]2+, demonstrating that enhanced charge separation can be correlated with device efficiency.
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Affiliation(s)
- Yejee Han
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
| | - Robert J. Dillon
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
| | - Cory J. Flynn
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
| | - Eric S. Rountree
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
| | - Leila Alibabaei
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
| | - James F. Cahoon
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
| | - John M. Papanikolas
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
| | - Jillian L. Dempsey
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
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7
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Eberhart MS, Bowers LMR, Shan B, Troian-Gautier L, Brennaman MK, Papanikolas JM, Meyer TJ. Completing a Charge Transport Chain for Artificial Photosynthesis. J Am Chem Soc 2018; 140:9823-9826. [DOI: 10.1021/jacs.8b06740] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Michael S. Eberhart
- Department of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
| | - Leah M. Rader Bowers
- Department of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
| | - Bing Shan
- Department of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
| | - Ludovic Troian-Gautier
- Department of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
| | - M. Kyle Brennaman
- Department of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
| | - John M. Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
| | - Thomas J. Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
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8
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Meyers JK, Kim S, Hill DJ, Cating EEM, Williams LJ, Kumbhar AS, McBride JR, Papanikolas JM, Cahoon JF. Self-Catalyzed Vapor-Liquid-Solid Growth of Lead Halide Nanowires and Conversion to Hybrid Perovskites. Nano Lett 2017; 17:7561-7568. [PMID: 29111750 DOI: 10.1021/acs.nanolett.7b03514] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Lead halide perovskites (LHPs) have shown remarkable promise for use in photovoltaics, photodetectors, light-emitting diodes, and lasers. Although solution-processed polycrystalline films are the most widely studied morphology, LHP nanowires (NWs) grown by vapor-phase processes offer the potential for precise control over crystallinity, phase, composition, and morphology. Here, we report the first demonstration of self-catalyzed vapor-liquid-solid (VLS) growth of lead halide (PbX2; X = Cl, Br, or I) NWs and conversion to LHP. We present a kinetic model of the PbX2 NW growth process in which a liquid Pb catalyst is supersaturated with halogen X through vapor-phase incorporation of both Pb and X, inducing growth of a NW. For PbI2, we show that the NWs are single-crystalline, oriented in the ⟨1̅21̅0⟩ direction, and composed of a stoichiometric PbI2 shaft with a spherical Pb tip. Low-temperature vapor-phase intercalation of methylammonium iodide converts the NWs to methylammonium lead iodide (MAPbI3) perovskite while maintaining the NW morphology. Single-NW experiments comparing measured extinction spectra with optical simulations show that the NWs exhibit a strong optical antenna effect, leading to substantially enhanced scattering efficiencies and to absorption efficiencies that can be more than twice that of thin films of the same thickness. Further development of the self-catalyzed VLS mechanism for lead halide and perovskite NWs should enable the rational design of nanostructures for various optoelectronic technologies, including potentially unique applications such as hot-carrier solar cells.
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Affiliation(s)
| | | | | | | | | | | | - James R McBride
- Vanderbilt Institute of Nanoscale Science and Engineering, Vanderbilt University , Nashville, Tennessee 37235, United States
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9
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Jones AL, Gish MK, Zeman CJ, Papanikolas JM, Schanze KS. Photoinduced Electron Transfer in Naphthalene Diimide End-Capped Thiophene Oligomers. J Phys Chem A 2017; 121:9579-9588. [DOI: 10.1021/acs.jpca.7b09095] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Austin L. Jones
- Department
of Chemistry and Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Melissa K. Gish
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Charles J. Zeman
- Department
of Chemistry and Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611-7200, United States
| | - John M. Papanikolas
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Kirk S. Schanze
- Department
of Chemistry, University of Texas at San Antonio, One UTSA Way, San Antonio, Texas 78249, United States
- Key
Laboratory of Resource Chemistry, Shanghai Normal University, Shanghai 200234, China
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10
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Alibabaei L, Dillon RJ, Reilly CE, Brennaman MK, Wee KR, Marquard SL, Papanikolas JM, Meyer TJ. Chromophore-Catalyst Assembly for Water Oxidation Prepared by Atomic Layer Deposition. ACS Appl Mater Interfaces 2017; 9:39018-39026. [PMID: 29035504 DOI: 10.1021/acsami.7b11905] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Visible-light-driven water splitting was investigated in a dye sensitized photoelectrosynthesis cell (DSPEC) based on a photoanode with a phosphonic acid-derivatized donor-π-acceptor (D-π-A) organic chromophore, 1, and the water oxidation catalyst [Ru(bda)(4-O(CH2)3P(O3H2)2-pyr)2], 2, (pyr = pyridine; bda = 2,2'-bipyridine-6,6'-dicarboxylate). The photoanode was prepared by using a layering strategy beginning with the organic dye anchored to an FTO|core/shell electrode, atomic layer deposition (ALD) of a thin layer (<1 nm) of TiO2, and catalyst binding through phosphonate linkage to the TiO2 layer. Device performance was evaluated by photocurrent measurements for core/shell photoanodes, with either SnO2 or nanoITO core materials, in acetate-buffered, aqueous solutions at pH 4.6 or 5.7. The absolute magnitudes of photocurrent changes with the core material, TiO2 spacer layer thickness, or pH, observed photocurrents were 2.5-fold higher in the presence of catalyst. The results of transient absorption measurements and DFT calculations show that electron injection by the photoexcited organic dye is ultrafast promoted by electronic interactions enabled by orientation of the dye's molecular orbitals on the electrode surface. Rapid injection is followed by recombination with the oxidized dye which is 95% complete by 1.5 ns. Although chromophore decomposition limits the efficiency of the DSPEC devices toward O2 production, the flexibility of the strategy presented here offers a new approach to photoanode design.
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Affiliation(s)
- Leila Alibabaei
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Robert J Dillon
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Caroline E Reilly
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - M Kyle Brennaman
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Kyung-Ryang Wee
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Seth L Marquard
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Thomas J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
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11
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Cating EEM, Pinion CW, Christesen JD, Christie CA, Grumstrup EM, Cahoon JF, Papanikolas JM. Probing Intrawire, Interwire, and Diameter-Dependent Variations in Silicon Nanowire Surface Trap Density with Pump-Probe Microscopy. Nano Lett 2017; 17:5956-5961. [PMID: 28895747 DOI: 10.1021/acs.nanolett.7b01876] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Surface trap density in silicon nanowires (NWs) plays a key role in the performance of many semiconductor NW-based devices. We use pump-probe microscopy to characterize the surface recombination dynamics on a point-by-point basis in 301 silicon NWs grown using the vapor-liquid-solid (VLS) method. The surface recombination velocity (S), a metric of the surface quality that is directly proportional to trap density, is determined by the relationship S = d/4τ from measurements of the recombination lifetime (τ) and NW diameter (d) at distinct spatial locations in individual NWs. We find that S varies by as much as 2 orders of magnitude between NWs grown at the same time but varies only by a factor of 2 or three within an individual NW. Although we find that, as expected, smaller-diameter NWs exhibit shorter τ, we also find that smaller wires exhibit higher values of S; this indicates that τ is shorter both because of the geometrical effect of smaller d and because of a poorer quality surface. These results highlight the need to consider interwire heterogeneity as well as diameter-dependent surface effects when fabricating NW-based devices.
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Affiliation(s)
- Emma E M Cating
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Christopher W Pinion
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Joseph D Christesen
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Caleb A Christie
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Erik M Grumstrup
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
- Department of Chemistry and Biochemistry, Montana State University , Bozeman, Montana 59717, United States
| | - James F Cahoon
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
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12
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Dillon RJ, Alibabaei L, Meyer TJ, Papanikolas JM. Enabling Efficient Creation of Long-Lived Charge-Separation on Dye-Sensitized NiO Photocathodes. ACS Appl Mater Interfaces 2017; 9:26786-26796. [PMID: 28731676 DOI: 10.1021/acsami.7b05856] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The hole-injection and recombination photophysics for NiO sensitized with RuP ([RuII(bpy)2(4,4'-(PO3H2)2-bpy)]2+) are explored. Ultrafast transient absorption (TA) measurements performed with an external electrochemical bias reveal the efficiency for productive hole-injection, that is, quenching of the dye excited state that results in a detectable charge-separated electron-hole pair, is linearly dependent on the electronic occupation of intragap states in the NiO film. Population of these states via a negative applied potential increases the efficiency from 0% to 100%. The results indicate the primary loss mechanism for dye-sensitized NiO is rapid nongeminate recombination enabled by the presence of latent holes in the surface of the NiO film. Our findings suggest a new design paradigm for NiO photocathodes and devices centered on the avoidance of this recombination pathway.
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Affiliation(s)
- Robert J Dillon
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27514, United States
| | - Leila Alibabaei
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27514, United States
| | - Thomas J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27514, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27514, United States
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13
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Morseth ZA, Pho TV, Sheridan MV, Meyer TJ, Schanze KS, Reynolds JR, Papanikolas JM. Interfacial Dynamics within an Organic Chromophore-Based Water Oxidation Molecular Assembly. ACS Appl Mater Interfaces 2017; 9:16651-16659. [PMID: 28441864 DOI: 10.1021/acsami.7b02713] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Photoinduced electron injection, intra-assembly electron transfer, and back-electron transfer are investigated in a single-site molecular assembly formed by covalently linking a phosphonated terthiophene (T3) chromophore to a Ru(terpyridine)(bipyridine)(L)2+ (L = MeCN or H2O) water oxidation catalyst adsorbed onto a mesoporous metal-oxide (MOx) film. Density functional theory calculations of the T3-trpy-Ru-L assembly indicate that the molecular components are strongly coupled with enhanced low-energy absorptions owing to the presence of an intraligand charge transfer (ILCT) transition between the T3 and trpy moieties. Ultrafast spectroscopy of the MOx//T3-trpy-Ru-L assemblies reveals that excitation of the surface-bound T3 chromophore results in ps-ns electron injection into the metal-oxide conduction band. Electron injection is followed by rapid (<35 ps) intra-assembly electron transfer from the RuII catalyst to regenerate the T3 chromophore with subsequent back-electron transfer on the microsecond time scale.
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Affiliation(s)
- Zachary A Morseth
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Toan V Pho
- School of Chemistry and Biochemistry, School of Materials Science and Engineering, Center for Organic Photonics and Electronics, Georgia Tech Polymer Network, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Matthew V Sheridan
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Thomas J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Kirk S Schanze
- Department of Chemistry, University of Texas at San Antonio , San Antonio, Texas 78249, United States
| | - John R Reynolds
- School of Chemistry and Biochemistry, School of Materials Science and Engineering, Center for Organic Photonics and Electronics, Georgia Tech Polymer Network, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
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14
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Gish MK, Lapides AM, Brennaman MK, Templeton JL, Meyer TJ, Papanikolas JM. Ultrafast Recombination Dynamics in Dye-Sensitized SnO 2/TiO 2 Core/Shell Films. J Phys Chem Lett 2016; 7:5297-5301. [PMID: 27973875 DOI: 10.1021/acs.jpclett.6b02388] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Interfacial dynamics are investigated in SnO2/TiO2 core/shell films derivatized with a Ru(II)-polypyridyl chromophore ([RuII(bpy)2(4,4'-(PO3H2)2bpy)]2+, RuP) using transient absorption methods. Electron injection from the chromophore into the TiO2 shell occurs within a few picoseconds after photoexcitation. Loss of the oxidized dye through recombination occurs across time scales spanning 10 orders of magnitude. The majority (60%) of charge recombination events occur shortly after injection (τ = 220 ps), while a small fraction (≤20%) of the oxidized chromophores persists for milliseconds. The lifetime of long-lived charge-separated states (CSS) depends exponentially on shell thickness, suggesting that the injected electrons reside in the SnO2 core and must tunnel through the TiO2 shell to recombine with oxidized dyes. While the core/shell architecture extends the lifetime in a small fraction of the CSS, making water oxidation possible, the subnanosecond recombination process has profound implications for the overall efficiencies of dye-sensitized photoelectrosynthesis cells (DSPECs).
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Affiliation(s)
- Melissa K Gish
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Alexander M Lapides
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - M Kyle Brennaman
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Joseph L Templeton
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Thomas J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
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15
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Brennaman MK, Dillon RJ, Alibabaei L, Gish MK, Dares CJ, Ashford DL, House RL, Meyer GJ, Papanikolas JM, Meyer TJ. Finding the Way to Solar Fuels with Dye-Sensitized Photoelectrosynthesis Cells. J Am Chem Soc 2016; 138:13085-13102. [PMID: 27654634 DOI: 10.1021/jacs.6b06466] [Citation(s) in RCA: 207] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The dye-sensitized photoelectrosynthesis cell (DSPEC) integrates high bandgap, nanoparticle oxide semiconductors with the light-absorbing and catalytic properties of designed chromophore-catalyst assemblies. The goals are photoelectrochemical water splitting into hydrogen and oxygen and reduction of CO2 by water to give oxygen and carbon-based fuels. Solar-driven water oxidation occurs at a photoanode and water or CO2 reduction at a cathode or photocathode initiated by molecular-level light absorption. Light absorption is followed by electron or hole injection, catalyst activation, and catalytic water oxidation or water/CO2 reduction. The DSPEC is of recent origin but significant progress has been made. It has the potential to play an important role in our energy future.
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Affiliation(s)
- M Kyle Brennaman
- Department of Chemistry, University of North Carolina at Chapel Hill , CB#3290, Chapel Hill, North Carolina 27599-3290, United States
| | - Robert J Dillon
- Department of Chemistry, University of North Carolina at Chapel Hill , CB#3290, Chapel Hill, North Carolina 27599-3290, United States
| | - Leila Alibabaei
- Department of Chemistry, University of North Carolina at Chapel Hill , CB#3290, Chapel Hill, North Carolina 27599-3290, United States
| | - Melissa K Gish
- Department of Chemistry, University of North Carolina at Chapel Hill , CB#3290, Chapel Hill, North Carolina 27599-3290, United States
| | - Christopher J Dares
- Department of Chemistry, University of North Carolina at Chapel Hill , CB#3290, Chapel Hill, North Carolina 27599-3290, United States
| | - Dennis L Ashford
- Department of Chemistry, University of North Carolina at Chapel Hill , CB#3290, Chapel Hill, North Carolina 27599-3290, United States
| | - Ralph L House
- Department of Chemistry, University of North Carolina at Chapel Hill , CB#3290, Chapel Hill, North Carolina 27599-3290, United States
| | - Gerald J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill , CB#3290, Chapel Hill, North Carolina 27599-3290, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill , CB#3290, Chapel Hill, North Carolina 27599-3290, United States
| | - Thomas J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill , CB#3290, Chapel Hill, North Carolina 27599-3290, United States
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16
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Morseth ZA, Pho TV, Gilligan AT, Dillon RJ, Schanze KS, Reynolds JR, Papanikolas JM. Role of Macromolecular Structure in the Ultrafast Energy and Electron Transfer Dynamics of a Light-Harvesting Polymer. J Phys Chem B 2016; 120:7937-48. [DOI: 10.1021/acs.jpcb.6b05589] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zachary A. Morseth
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Toan V. Pho
- School
of Chemistry and Biochemistry, School of Materials Science and Engineering,
Center for Organic Photonics and Electronics, Georgia Tech Polymer
Network, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Alexander T. Gilligan
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Robert J. Dillon
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Kirk S. Schanze
- Department
of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - John R. Reynolds
- School
of Chemistry and Biochemistry, School of Materials Science and Engineering,
Center for Organic Photonics and Electronics, Georgia Tech Polymer
Network, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - John M. Papanikolas
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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17
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Call RW, Alibabaei L, Dillon RJ, Knauf RR, Nayak A, Dempsey JL, Papanikolas JM, Lopez R. Growth and Post-Deposition Treatments of SrTiO3 Films for Dye-Sensitized Photoelectrosynthesis Cell Applications. ACS Appl Mater Interfaces 2016; 8:12282-12290. [PMID: 27128813 DOI: 10.1021/acsami.6b01289] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Sensitized SrTiO3 films were evaluated as potential photoanodes for dye-sensitized photoelectrosynthesis cells (DSPECs). The SrTiO3 films were grown via pulsed laser deposition (PLD) on a transparent conducting oxide (fluorine-doped tin oxide, FTO) substrate, annealed, and then loaded with zinc(II) 5,10,15-tris(mesityl)-20-[(dihydroxyphosphoryl)phenyl] porphyrin (MPZnP). When paired with a platinum wire counter electrode and an Ag/AgCl reference electrode these sensitized films exhibited photocurrent densities on the order of 350 nA/cm(2) under 0 V applied bias conditions versus a normal hydrogen electrode (NHE) and 75 mW/cm(2) illumination at a wavelength of 445 nm. The conditions of the post-deposition annealing step-namely, a high-temperature reducing atmosphere-proved to be the most important growth parameters for increasing photocurrent in these electrodes.
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Affiliation(s)
- Robert W Call
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Leila Alibabaei
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Robert J Dillon
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Robin R Knauf
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Animesh Nayak
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Jillian L Dempsey
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Rene Lopez
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
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18
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Pho TV, Sheridan MV, Morseth ZA, Sherman BD, Meyer TJ, Papanikolas JM, Schanze KS, Reynolds JR. Efficient Light-Driven Oxidation of Alcohols Using an Organic Chromophore-Catalyst Assembly Anchored to TiO2. ACS Appl Mater Interfaces 2016; 8:9125-9133. [PMID: 27032068 DOI: 10.1021/acsami.6b00932] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The ligand 5-PO3H2-2,2':5',2″-terthiophene-5-trpy, T3 (trpy = 2,2':6',2″-terpyridine), was prepared and studied in aqueous solutions along with its metal complex assembly [Ru(T3)(bpy)(OH2)](2+) (T3-Ru-OH2, bpy = 2,2'-bipyridine). T3 contains a phosphonic acid group for anchoring to a TiO2 photoanode under aqueous conditions, a terthiophene fragment for light absorption and electron injection into TiO2, and a terminal trpy ligand for the construction of assemblies comprising a molecular oxidation catalyst. At a TiO2 photoanode, T3 displays efficient injection at pH 4.35 as evidenced by the high photocurrents (∼350 uA/cm(2)) arising from hydroquinone oxidation. Addition of [Ru(bpy)(OTf)][OTf]2 (bpy = 2,2'-bipyridine, OTf(-) = triflate) to T3 at the free trpy ligand forms the molecular assembly, T3-Ru-OH2, with the oxidative catalyst fragment: [Ru(trpy)(bpy)(OH2)](2+). The new assembly, T3-Ru-OH2, was used to perform efficient light-driven oxidation of phenol (230 μA/cm(2)) and benzyl alcohol (25 μA/cm(2)) in a dye-sensitized photoelectrosynthesis cell.
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Affiliation(s)
- Toan V Pho
- School of Chemistry & Biochemistry, School of Materials Science & Engineering, Center for Organic Photonics and Electronics, Georgia Tech Polymer Network, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Matthew V Sheridan
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Zachary A Morseth
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Benjamin D Sherman
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Thomas J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Kirk S Schanze
- Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida , Gainesville, Florida 32611, United States
| | - John R Reynolds
- School of Chemistry & Biochemistry, School of Materials Science & Engineering, Center for Organic Photonics and Electronics, Georgia Tech Polymer Network, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
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19
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Zigler DF, Morseth ZA, Wang L, Ashford DL, Brennaman MK, Grumstrup EM, Brigham EC, Gish MK, Dillon RJ, Alibabaei L, Meyer GJ, Meyer TJ, Papanikolas JM. Disentangling the Physical Processes Responsible for the Kinetic Complexity in Interfacial Electron Transfer of Excited Ru(II) Polypyridyl Dyes on TiO2. J Am Chem Soc 2016; 138:4426-38. [DOI: 10.1021/jacs.5b12996] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- David F. Zigler
- Caudill, Kenan, and Murray
Laboratories, Department of Chemistry, University of North Carolina at Chapel Hill, Campus
Box 3290, Chapel Hill, North Carolina 27599, United States
| | - Zachary A. Morseth
- Caudill, Kenan, and Murray
Laboratories, Department of Chemistry, University of North Carolina at Chapel Hill, Campus
Box 3290, Chapel Hill, North Carolina 27599, United States
| | - Li Wang
- Caudill, Kenan, and Murray
Laboratories, Department of Chemistry, University of North Carolina at Chapel Hill, Campus
Box 3290, Chapel Hill, North Carolina 27599, United States
| | - Dennis L. Ashford
- Caudill, Kenan, and Murray
Laboratories, Department of Chemistry, University of North Carolina at Chapel Hill, Campus
Box 3290, Chapel Hill, North Carolina 27599, United States
| | - M. Kyle Brennaman
- Caudill, Kenan, and Murray
Laboratories, Department of Chemistry, University of North Carolina at Chapel Hill, Campus
Box 3290, Chapel Hill, North Carolina 27599, United States
| | - Erik M. Grumstrup
- Caudill, Kenan, and Murray
Laboratories, Department of Chemistry, University of North Carolina at Chapel Hill, Campus
Box 3290, Chapel Hill, North Carolina 27599, United States
| | - Erinn C. Brigham
- Caudill, Kenan, and Murray
Laboratories, Department of Chemistry, University of North Carolina at Chapel Hill, Campus
Box 3290, Chapel Hill, North Carolina 27599, United States
| | - Melissa K. Gish
- Caudill, Kenan, and Murray
Laboratories, Department of Chemistry, University of North Carolina at Chapel Hill, Campus
Box 3290, Chapel Hill, North Carolina 27599, United States
| | - Robert J. Dillon
- Caudill, Kenan, and Murray
Laboratories, Department of Chemistry, University of North Carolina at Chapel Hill, Campus
Box 3290, Chapel Hill, North Carolina 27599, United States
| | - Leila Alibabaei
- Caudill, Kenan, and Murray
Laboratories, Department of Chemistry, University of North Carolina at Chapel Hill, Campus
Box 3290, Chapel Hill, North Carolina 27599, United States
| | - Gerald J. Meyer
- Caudill, Kenan, and Murray
Laboratories, Department of Chemistry, University of North Carolina at Chapel Hill, Campus
Box 3290, Chapel Hill, North Carolina 27599, United States
| | - Thomas J. Meyer
- Caudill, Kenan, and Murray
Laboratories, Department of Chemistry, University of North Carolina at Chapel Hill, Campus
Box 3290, Chapel Hill, North Carolina 27599, United States
| | - John M. Papanikolas
- Caudill, Kenan, and Murray
Laboratories, Department of Chemistry, University of North Carolina at Chapel Hill, Campus
Box 3290, Chapel Hill, North Carolina 27599, United States
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20
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Leem G, Morseth ZA, Wee KR, Jiang J, Brennaman MK, Papanikolas JM, Schanze KS. Polymer-Based Ruthenium(II) Polypyridyl Chromophores on TiO2 for Solar Energy Conversion. Chem Asian J 2016; 11:1257-67. [PMID: 26854269 DOI: 10.1002/asia.201501384] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Indexed: 11/07/2022]
Abstract
A polychromophoric light-harvesting assembly featuring a polystyrene (PS) backbone with ionic carboxylate-functionalized Ru(II) polypyridyl complexes as pendant groups (PS-Ru-A) was synthesized and successfully anchored onto mesoporous structured TiO2 films (TiO2 //PS-Ru-A). Studies of the resulting TiO2 //PS-Ru-A films carried out by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) confirmed that the ionic carboxylated Ru(II) complexes from PS-Ru-A led to the surface immobilization on the TiO2 film. Monochromatic light photocurrent spectroscopy (IPCE) and white light (AM1.5G) current-voltage studies of dye-sensitized solar cells using the TiO2 //PS-Ru-A photoanode give rise to modest photocurrent and white light efficiency (24 % peak IPCE and 0.33 % PCE, respectively). The photostability of surface-bound TiO2 //PS-Ru-A films was tested and compared to a monomeric Ru(II) complex (TiO2 //Ru-A), showing an enhancement of ∼14 % in the photostability of PS-Ru-A. Transient absorption measurements reveal that electron injection from surface-bound pendants occurs on the picosecond time scale, similar to TiO2 //Ru-A, while time-resolved emission measurements reveal delayed electron injection occurring in TiO2 //PS-Ru-A on the nanosecond time scale, underscoring energy transport from unbound to surface-bound complexes. Additionally, charge recombination is delayed in PS-Ru-A, pointing towards intra-assembly hole transport to complexes away from the surface. Molecular dynamics simulations of PS-Ru-A in fluid solution indicate that a majority of the pendant Ru(II) complexes lie within 10-20 Å of each other, facilitating efficient energy- and charge transport among the pendant complexes.
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Affiliation(s)
- Gyu Leem
- Department of Chemistry, University of Florida, Gainesville, Florida, 32611, United States
| | - Zachary A Morseth
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States
| | - Kyung-Ryang Wee
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States
| | - Junlin Jiang
- Department of Chemistry, University of Florida, Gainesville, Florida, 32611, United States
| | - M Kyle Brennaman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599, United States
| | - Kirk S Schanze
- Department of Chemistry, University of Florida, Gainesville, Florida, 32611, United States.
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21
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Cating EEM, Pinion CW, Van Goethem EM, Gabriel MM, Cahoon JF, Papanikolas JM. Imaging Spatial Variations in the Dissipation and Transport of Thermal Energy within Individual Silicon Nanowires Using Ultrafast Microscopy. Nano Lett 2016; 16:434-439. [PMID: 26629610 DOI: 10.1021/acs.nanolett.5b04075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Thermal management is an important consideration for most nanoelectronic devices, and an understanding of the thermal conductivity of individual device components is critical for the design of thermally efficient systems. However, it can be difficult to directly probe local changes in thermal conductivity within a nanoscale system. Here, we utilize the time-resolved and diffraction-limited imaging capabilities of ultrafast pump-probe microscopy to determine, in a contact-free configuration, the local thermal conductivity in individual Si nanowires (NWs). By suspending single NWs across microfabricated trenches in a quartz substrate, the properties of the same NW both on and off the substrate are directly compared. We find the substrate has no effect on the recombination lifetime or diffusion length of photogenerated charge carriers; however, it significantly impacts the thermal relaxation properties of the NW. In substrate-supported regions, thermal energy deposited into the lattice by the ultrafast laser pulse dissipates within ∼10 ns through thermal diffusion and coupling to the substrate. In suspended regions, the thermal energy persists for over 100 ns, and we directly image the time-resolved spatial motion of the thermal signal. Quantitative analysis of the transient images permits direct determination of the NW's local thermal conductivity, which we find to be a factor of ∼4 smaller than in bulk Si. Our results point to the strong potential of pump-probe microscopy to be used as an all-optical method to quantify the effects of localized environment and morphology on the thermal transport characteristics of individual nanostructured components.
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Affiliation(s)
- Emma E M Cating
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Christopher W Pinion
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Erika M Van Goethem
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Michelle M Gabriel
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - James F Cahoon
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
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22
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Goswami S, Gish MK, Wang J, Winkel RW, Papanikolas JM, Schanze KS. π-Conjugated Organometallic Isoindigo Oligomer and Polymer Chromophores: Singlet and Triplet Excited State Dynamics and Application in Polymer Solar Cells. ACS Appl Mater Interfaces 2015; 7:26828-26838. [PMID: 26561718 DOI: 10.1021/acsami.5b09041] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
An isoindigo based π-conjugated oligomer and polymer that contain cyclometalated platinum(II) "auxochrome" units were subjected to photophysical characterization, and application of the polymer in bulk heterojunction polymer solar cells with PCBM acceptor was examined. The objective of the study was to explore the effect of the heavy metal centers on the excited state properties, in particular, intersystem crossing to a triplet (exciton) state, and further how this would influence the performance of the organometallic polymer in solar cells. The materials were characterized by electrochemistry, ground state absorption, emission, and picosecond-nanosecond transient absorption spectroscopy. Electrochemical measurements indicate that the cyclometalated units have a significant impact on the HOMO energy level of the chromophores, but little effect on the LUMO, which is consistent with localization of the LUMO on the isoindigo acceptor unit. Picosecond-nanosecond transient absorption spectroscopy reveals a transient with ∼100 ns lifetime that is assigned to a triplet excited state that is produced by intersystem crossing from a singlet state on a time scale of ∼130 ps. This is the first time that a triplet state has been observed for isoindigo π-conjugated chromophores. The performance of the polymer in bulk heterojunction solar cells was explored with PC61BM as an acceptor. The performance of the cells was optimum at a relatively high PCBM loading (1:6, polymer:PCBM), but the overall efficiency was relatively low with power conversion efficiency (PCE) of 0.22%. Atomic force microscopy of blend films reveals that the length scale of the phase separation decreases with increasing PCBM content, suggesting a reason for the increase in PCE with acceptor loading. Energetic considerations show that the triplet state in the polymer is too low in energy to undergo charge separation with PCBM. Further, due to the relatively low LUMO energy of the polymer, charge transfer from the singlet to PCBM is only weakly exothermic, which is believed to be the reason that the photocurrent efficiency is relatively low.
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Affiliation(s)
- Subhadip Goswami
- Department of Chemistry and Center for Macromolecular Science and Engineering, University, of Florida , P. O. Box 117200, Gainesville, Florida 32611-7200, United States
| | - Melissa K Gish
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Jiliang Wang
- Department of Chemistry and Center for Macromolecular Science and Engineering, University, of Florida , P. O. Box 117200, Gainesville, Florida 32611-7200, United States
| | - Russell W Winkel
- Department of Chemistry and Center for Macromolecular Science and Engineering, University, of Florida , P. O. Box 117200, Gainesville, Florida 32611-7200, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
| | - Kirk S Schanze
- Department of Chemistry and Center for Macromolecular Science and Engineering, University, of Florida , P. O. Box 117200, Gainesville, Florida 32611-7200, United States
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23
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Brennaman MK, Norris MR, Gish MK, Grumstrup EM, Alibabaei L, Ashford DL, Lapides AM, Papanikolas JM, Templeton JL, Meyer TJ. Ultrafast, Light-Induced Electron Transfer in a Perylene Diimide Chromophore-Donor Assembly on TiO2. J Phys Chem Lett 2015; 6:4736-42. [PMID: 26554498 DOI: 10.1021/acs.jpclett.5b02194] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Surface-bound, perylenediimide (PDI)-based molecular assemblies have been synthesized on nanocrystalline TiO2 by reaction of a dianhydride with a surface-bound aniline and succinimide bonding. In a second step, the Fe(II) polypyridyl complex [Fe(II)(tpy-PhNH2)2](2+) was added to the outside of the film, also by succinimide bonding. Ultrafast transient absorption measurements in 0.1 M HClO4 reveal that electron injection into TiO2 by (1)PDI* does not occur, but rather leads to the ultrafast formation of the redox-separated pair PDI(•+),PDI(•-), which decays with complex kinetics (τ1 = 0.8 ps, τ2 = 15 ps, and τ3 = 1500 ps). With the added Fe(II) polypyridyl complex, rapid (<25 ps) oxidation of Fe(II) by the PDI(•+),PDI(•-) redox pair occurs to give Fe(III),PDI(•-) persisting for >400 μs in the film environment.
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Affiliation(s)
- M Kyle Brennaman
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Michael R Norris
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Melissa K Gish
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Erik M Grumstrup
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Leila Alibabaei
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Dennis L Ashford
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Alexander M Lapides
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - John M Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Joseph L Templeton
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
| | - Thomas J Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
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24
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Ashford DL, Gish MK, Vannucci AK, Brennaman MK, Templeton JL, Papanikolas JM, Meyer TJ. Molecular Chromophore–Catalyst Assemblies for Solar Fuel Applications. Chem Rev 2015; 115:13006-49. [DOI: 10.1021/acs.chemrev.5b00229] [Citation(s) in RCA: 363] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Dennis L. Ashford
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel
Hill, North Carolina 27599, United States
| | - Melissa K. Gish
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel
Hill, North Carolina 27599, United States
| | - Aaron K. Vannucci
- Department
of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208, United States
| | - M. Kyle Brennaman
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel
Hill, North Carolina 27599, United States
| | - Joseph L. Templeton
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel
Hill, North Carolina 27599, United States
| | - John M. Papanikolas
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel
Hill, North Carolina 27599, United States
| | - Thomas J. Meyer
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel
Hill, North Carolina 27599, United States
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25
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Morseth ZA, Wang L, Puodziukynaite E, Leem G, Gilligan AT, Meyer TJ, Schanze KS, Reynolds JR, Papanikolas JM. Ultrafast dynamics in multifunctional Ru(II)-loaded polymers for solar energy conversion. Acc Chem Res 2015; 48:818-27. [PMID: 25647081 DOI: 10.1021/ar500382u] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The use of sunlight to make chemical fuels (i.e., solar fuels) is an attractive approach in the quest to develop sustainable energy sources. Using nature as a guide, assemblies for artificial photosynthesis will need to perform multiple functions. They will need to be able to harvest light across a broad region of the solar spectrum, transport excited-state energy to charge-separation sites, and then transport and store redox equivalents for use in the catalytic reactions that produce chemical fuels. This multifunctional behavior will require the assimilation of multiple components into a single macromolecular system. A wide variety of different architectures including porphyrin arrays, peptides, dendrimers, and polymers have been explored, with each design posing unique challenges. Polymer assemblies are attractive due to their relative ease of production and facile synthetic modification. However, their disordered nature gives rise to stochastic dynamics not present in more ordered assemblies. The rational design of assemblies requires a detailed understanding of the energy and electron transfer events that follow light absorption, which can occur on time scales ranging from femtoseconds to hundreds of microseconds, necessitating the use of sophisticated techniques. We have used a combination of time-resolved absorption and emission spectroscopies with observation times that span 9 orders of magnitude to follow the excited-state evolution within polymer-based molecular assemblies. We complement experimental observations with molecular dynamics simulations to develop a microscopic view of these dynamics. This Account provides an overview of our work on polymers decorated with pendant Ru(II) chromophores, both in solution and on surfaces. We have examined site-to-site energy transport among the Ru(II) complexes, and in systems incorporating π-conjugated polymers, we have observed ultrafast formation of a long-lived charge-separated state. When attached to TiO2, these assemblies exhibit multifunctional behavior in which photon absorption is followed by energy transport to the surface and electron injection to produce an oxidized metal complex. The oxidizing equivalent is then transferred to the conjugated polymer, giving rise to a long-lived charge-separated state.
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Affiliation(s)
- Zachary A. Morseth
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Li Wang
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Egle Puodziukynaite
- Department
of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Gyu Leem
- Department
of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Alexander T. Gilligan
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Thomas J. Meyer
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Kirk S. Schanze
- Department
of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - John R. Reynolds
- School
of Chemistry and Biochemistry, School of Materials Science and Engineering,
Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - John M. Papanikolas
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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26
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Farnum BH, Morseth ZA, Brennaman MK, Papanikolas JM, Meyer TJ. Application of Degenerately Doped Metal Oxides in the Study of Photoinduced Interfacial Electron Transfer. J Phys Chem B 2015; 119:7698-711. [DOI: 10.1021/jp512624u] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Byron H. Farnum
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Zachary A. Morseth
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - M. Kyle Brennaman
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - John M. Papanikolas
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Thomas J. Meyer
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
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27
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Leem G, Keinan S, Jiang J, Chen Z, Pho T, Morseth ZA, Hu Z, Puodziukynaite E, Fang Z, Papanikolas JM, Reynolds JR, Schanze KS. Ru(bpy)32+ derivatized polystyrenes constructed by nitroxide-mediated radical polymerization. Relationship between polymer chain length, structure and photophysical properties. Polym Chem 2015. [DOI: 10.1039/c5py01289a] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A series of polystyrene-based light harvesting polymers featuring pendant polypyridyl ruthenium complexes has been synthesized.
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28
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Ashford DL, Brennaman MK, Brown RJ, Keinan S, Concepcion JJ, Papanikolas JM, Templeton JL, Meyer TJ. Varying the Electronic Structure of Surface-Bound Ruthenium(II) Polypyridyl Complexes. Inorg Chem 2014; 54:460-9. [DOI: 10.1021/ic501682k] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Dennis L. Ashford
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
| | - M. Kyle Brennaman
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
| | - Robert J. Brown
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
| | - Shahar Keinan
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
| | - Javier J. Concepcion
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
| | - John M. Papanikolas
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
| | - Joseph L. Templeton
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
| | - Thomas J. Meyer
- Department
of Chemistry, University of North Carolina at Chapel Hill, CB 3290, Chapel Hill, North Carolina 27599, United States
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29
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Grumstrup EM, Gabriel MM, Pinion CW, Parker JK, Cahoon JF, Papanikolas JM. Reversible strain-induced electron-hole recombination in silicon nanowires observed with femtosecond pump-probe microscopy. Nano Lett 2014; 14:6287-6292. [PMID: 25259929 DOI: 10.1021/nl5026166] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Strain-induced changes to the electronic structure of nanoscale materials provide a promising avenue for expanding the optoelectronic functionality of semiconductor nanostructures in device applications. Here we use pump-probe microscopy with femtosecond temporal resolution and submicron spatial resolution to characterize charge-carrier recombination and transport dynamics in silicon nanowires (NWs) locally strained by bending deformation. The electron-hole recombination rate increases with strain for values above a threshold of ∼1% and, in highly strained (∼5%) regions of the NW, increases 6-fold. The changes in recombination rate are independent of NW diameter and reversible upon reduction of the applied strain, indicating the effect originates from alterations to the NW bulk electronic structure rather than introduction of defects. The results highlight the strong relationship between strain, electronic structure, and charge-carrier dynamics in low-dimensional semiconductor systems, and we anticipate the results will assist the development of strain-enabled optoelectronic devices with indirect-bandgap materials such as silicon.
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Affiliation(s)
- Erik M Grumstrup
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599, United States
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30
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Farnum BH, Morseth ZA, Brennaman MK, Papanikolas JM, Meyer TJ. Driving Force Dependent, Photoinduced Electron Transfer at Degenerately Doped, Optically Transparent Semiconductor Nanoparticle Interfaces. J Am Chem Soc 2014; 136:15869-72. [DOI: 10.1021/ja508862h] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Byron H. Farnum
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Zachary A. Morseth
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - M. Kyle Brennaman
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - John M. Papanikolas
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Thomas J. Meyer
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
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31
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Gabriel MM, Grumstrup EM, Kirschbrown JR, Pinion CW, Christesen JD, Zigler DF, Cating EEM, Cahoon JF, Papanikolas JM. Imaging charge separation and carrier recombination in nanowire p-i-n junctions using ultrafast microscopy. Nano Lett 2014; 14:3079-3087. [PMID: 24867088 DOI: 10.1021/nl5012118] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Silicon nanowires incorporating p-type/n-type (p-n) junctions have been introduced as basic building blocks for future nanoscale electronic components. Controlling charge flow through these doped nanostructures is central to their function, yet our understanding of this process is inferred from measurements that average over entire structures or integrate over long times. Here, we have used femtosecond pump-probe microscopy to directly image the dynamics of photogenerated charge carriers in silicon nanowires encoded with p-n junctions along the growth axis. Initially, motion is dictated by carrier-carrier interactions, resulting in diffusive spreading of the neutral electron-hole cloud. Charge separation occurs at longer times as the carrier distribution reaches the edges of the depletion region, leading to a persistent electron population in the n-type region. Time-resolved visualization of the carrier dynamics yields clear, direct information on fundamental drift, diffusion, and recombination processes in these systems, providing a powerful tool for understanding and improving materials for nanotechnology.
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Affiliation(s)
- Michelle M Gabriel
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
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32
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Bettis SE, Hanson K, Wang L, Gish MK, Concepcion JJ, Fang Z, Meyer TJ, Papanikolas JM. Photophysical Characterization of a Chromophore/Water Oxidation Catalyst Containing a Layer-by-Layer Assembly on Nanocrystalline TiO2 Using Ultrafast Spectroscopy. J Phys Chem A 2014; 118:10301-8. [DOI: 10.1021/jp411139j] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Stephanie E. Bettis
- Department of Chemistry, University of North Carolina, CB 3290, Chapel
Hill, North Carolina 27599, United States
| | - Kenneth Hanson
- Department of Chemistry, University of North Carolina, CB 3290, Chapel
Hill, North Carolina 27599, United States
| | - Li Wang
- Department of Chemistry, University of North Carolina, CB 3290, Chapel
Hill, North Carolina 27599, United States
| | - Melissa K. Gish
- Department of Chemistry, University of North Carolina, CB 3290, Chapel
Hill, North Carolina 27599, United States
| | - Javier J. Concepcion
- Department of Chemistry, University of North Carolina, CB 3290, Chapel
Hill, North Carolina 27599, United States
| | - Zhen Fang
- Department of Chemistry, University of North Carolina, CB 3290, Chapel
Hill, North Carolina 27599, United States
| | - Thomas J. Meyer
- Department of Chemistry, University of North Carolina, CB 3290, Chapel
Hill, North Carolina 27599, United States
| | - John M. Papanikolas
- Department of Chemistry, University of North Carolina, CB 3290, Chapel
Hill, North Carolina 27599, United States
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33
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Farnum BH, Morseth ZA, Lapides AM, Rieth AJ, Hoertz PG, Brennaman MK, Papanikolas JM, Meyer TJ. Photoinduced Interfacial Electron Transfer within a Mesoporous Transparent Conducting Oxide Film. J Am Chem Soc 2014; 136:2208-11. [DOI: 10.1021/ja4106418] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Byron H. Farnum
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Zachary A. Morseth
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Alexander M. Lapides
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Adam J. Rieth
- RTI International, Research Triangle Park, North Carolina 27709-2194, United States
| | - Paul G. Hoertz
- RTI International, Research Triangle Park, North Carolina 27709-2194, United States
| | - M. Kyle Brennaman
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - John M. Papanikolas
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
| | - Thomas J. Meyer
- Department
of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, United States
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34
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Puodziukynaite E, Wang L, Schanze KS, Papanikolas JM, Reynolds JR. Poly(fluorene-co-thiophene)-based ionic transition-metal complex polymers for solar energy harvesting and storage applications. Polym Chem 2014. [DOI: 10.1039/c3py01582c] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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35
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Chen Z, Grumstrup EM, Gilligan AT, Papanikolas JM, Schanze KS. Light-Harvesting Polymers: Ultrafast Energy Transfer in Polystyrene-Based Arrays of π-Conjugated Chromophores. J Phys Chem B 2013; 118:372-8. [DOI: 10.1021/jp411565p] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Zhuo Chen
- Department
of Chemistry and Center for Macromolecular Science and Engineering, University of Florida, P.O. Box 117200, Gainesville, Florida 32611-7200, United States
| | - Erik M. Grumstrup
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Alexander T. Gilligan
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - John M. Papanikolas
- Department
of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Kirk S. Schanze
- Department
of Chemistry and Center for Macromolecular Science and Engineering, University of Florida, P.O. Box 117200, Gainesville, Florida 32611-7200, United States
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36
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Grumstrup EM, Chen Z, Vary RP, Moran AM, Schanze KS, Papanikolas JM. Frequency Modulated Femtosecond Stimulated Raman Spectroscopy of Ultrafast Energy Transfer in a Donor–Acceptor Copolymer. J Phys Chem B 2013; 117:8245-55. [DOI: 10.1021/jp404498u] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Erik M. Grumstrup
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel
Hill, North Carolina 27514, United States
| | - Zhuo Chen
- Department of Chemistry and
Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - Ryan P. Vary
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel
Hill, North Carolina 27514, United States
| | - Andrew M. Moran
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel
Hill, North Carolina 27514, United States
| | - Kirk S. Schanze
- Department of Chemistry and
Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611, United States
| | - John M. Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel
Hill, North Carolina 27514, United States
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37
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Brennaman MK, Fleming CN, Slate CA, Serron SA, Bettis SE, Erickson BW, Papanikolas JM, Meyer TJ. Distance Dependence of Intrahelix RuII* to OsII Polypyridyl Excited-State Energy Transfer in Oligoproline Assemblies. J Phys Chem B 2013; 117:6352-63. [DOI: 10.1021/jp400312f] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. Kyle Brennaman
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
27599, United States
| | - Cavan N. Fleming
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
27599, United States
| | - Cheryl A. Slate
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
27599, United States
| | - Scafford A. Serron
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
27599, United States
| | - Stephanie E. Bettis
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
27599, United States
| | - Bruce W. Erickson
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
27599, United States
| | - John M. Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
27599, United States
| | - Thomas J. Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
27599, United States
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38
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Ma D, Bettis SE, Hanson K, Minakova M, Alibabaei L, Fondrie W, Ryan DM, Papoian GA, Meyer TJ, Waters ML, Papanikolas JM. Interfacial Energy Conversion in RuII Polypyridyl-Derivatized Oligoproline Assemblies on TiO2. J Am Chem Soc 2013; 135:5250-3. [DOI: 10.1021/ja312143h] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Da Ma
- Department of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - Stephanie E. Bettis
- Department of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - Kenneth Hanson
- Department of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - Maria Minakova
- Department of Chemistry and
Biochemistry, University of Maryland, College
Park, Maryland 20742, United States
| | - Leila Alibabaei
- Department of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - William Fondrie
- Department of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - Derek M. Ryan
- Department of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - Garegin A. Papoian
- Department of Chemistry and
Biochemistry, University of Maryland, College
Park, Maryland 20742, United States
| | - Thomas J. Meyer
- Department of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - Marcey L. Waters
- Department of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - John M. Papanikolas
- Department of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
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39
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Gabriel MM, Kirschbrown JR, Christesen JD, Pinion CW, Zigler DF, Grumstrup EM, Mehl BP, Cating EEM, Cahoon JF, Papanikolas JM. Direct imaging of free carrier and trap carrier motion in silicon nanowires by spatially-separated femtosecond pump-probe microscopy. Nano Lett 2013; 13:1336-1340. [PMID: 23421654 DOI: 10.1021/nl400265b] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
We have developed a pump-probe microscope capable of exciting a single semiconductor nanostructure in one location and probing it in another with both high spatial and temporal resolution. Experiments performed on Si nanowires enable a direct visualization of the charge cloud produced by photoexcitation at a localized spot as it spreads along the nanowire axis. The time-resolved images show clear evidence of rapid diffusional spreading and recombination of the free carriers, which is consistent with ambipolar diffusion and a surface recombination velocity of ∼10(4) cm/s. The free carrier dynamics are followed by trap carrier migration on slower time scales.
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Affiliation(s)
- Michelle M Gabriel
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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Hanson K, Wilger DJ, Jones ST, Harrison DP, Bettis SE, Luo H, Papanikolas JM, Waters ML, Meyer TJ. Electron transfer dynamics of peptide-derivatized RuII-polypyridyl complexes on nanocrystalline metal oxide films. Biopolymers 2013; 100:25-37. [DOI: 10.1002/bip.22152] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2012] [Revised: 08/09/2012] [Accepted: 08/27/2012] [Indexed: 12/24/2022]
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41
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Christesen JD, Pinion CW, Grumstrup EM, Papanikolas JM, Cahoon JF. Synthetically encoding 10 nm morphology in silicon nanowires. Nano Lett 2013; 13:6281-6. [PMID: 24274858 DOI: 10.1021/nl403909r] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Si nanowires (NWs) have been widely explored as a platform for photonic and electronic technologies. Here, we report a bottom-up method to break the conventional "wire" symmetry and synthetically encode a high-resolution array of arbitrary shapes, including nanorods, sinusoids, bowties, tapers, nanogaps, and gratings, along the NW growth axis. Rapid modulation of phosphorus doping combined with selective wet-chemical etching enabled morphological features as small as 10 nm to be patterned over wires more than 50 μm in length. This capability fundamentally expands the set of technologies that can be realized with Si NWs, and as proof-of-concept, we demonstrate two distinct applications. First, nanogap-encoded NWs were used as templates for Noble metals, yielding plasmonic structures with tunable resonances for surface-enhanced Raman imaging. Second, core/shell Si/SiO2 nanorods were integrated into electronic devices that exhibit resistive switching, enabling nonvolatile memory storage. Moving beyond these initial examples, we envision this method will become a generic route to encode new functionality in semiconductor NWs.
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Affiliation(s)
- Joseph D Christesen
- Department of Chemistry, University of North Carolina at Chapel Hill , Chapel Hill, North Carolina 27599-3290, United States
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42
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Westlake BC, Paul JJ, Bettis SE, Hampton SD, Mehl BP, Meyer TJ, Papanikolas JM. Base-Induced Phototautomerization in 7-Hydroxy-4-(trifluoromethyl)coumarin. J Phys Chem B 2012. [DOI: 10.1021/jp308505p] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Brittany C. Westlake
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Jared J. Paul
- Department of Chemistry, Villanova University, Villanova, Pennsylvania
19085,
United States
| | - Stephanie E. Bettis
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Shaun D. Hampton
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Brian P. Mehl
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - Thomas J. Meyer
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
| | - John M. Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United States
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43
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Mehl BP, Kirschbrown JR, Gabriel MM, House RL, Papanikolas JM. Pump–Probe Microscopy: Spatially Resolved Carrier Dynamics in ZnO Rods and the Influence of Optical Cavity Resonator Modes. J Phys Chem B 2012; 117:4390-8. [DOI: 10.1021/jp307089h] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Brian P. Mehl
- Department of Chemistry, Caudill
Laboratories, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United
States
| | - Justin R. Kirschbrown
- Department of Chemistry, Caudill
Laboratories, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United
States
| | - Michelle M. Gabriel
- Department of Chemistry, Caudill
Laboratories, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United
States
| | - Ralph L. House
- Department of Chemistry, Caudill
Laboratories, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United
States
| | - John M. Papanikolas
- Department of Chemistry, Caudill
Laboratories, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-3290, United
States
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44
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Lampert ZE, Reynolds CL, Papanikolas JM, Aboelfotoh MO. Controlling Morphology and Chain Aggregation in Semiconducting Conjugated Polymers: The Role of Solvent on Optical Gain in MEH-PPV. J Phys Chem B 2012; 116:12835-41. [DOI: 10.1021/jp304199u] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zach E. Lampert
- Department of Materials
Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919,
United States
| | - C. Lewis Reynolds
- Department of Materials
Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919,
United States
| | - John M. Papanikolas
- Department of Chemistry, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - M. Osama Aboelfotoh
- Department of Materials
Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695-7919,
United States
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45
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Wang L, Puodziukynaite E, Vary RP, Grumstrup EM, Walczak RM, Zolotarskaya OY, Schanze KS, Reynolds JR, Papanikolas JM. Competition between Ultrafast Energy Flow and Electron Transfer in a Ru(II)-Loaded Polyfluorene Light-Harvesting Polymer. J Phys Chem Lett 2012; 3:2453-2457. [PMID: 26292132 DOI: 10.1021/jz300979j] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This Letter describes the synthesis and photophysical characterization of a Ru(II) assembly consisting of metal polypyridyl complexes linked together by a polyfluorene scaffold. Unlike many scaffolds incorporating saturated linkages, the conjugated polymer in this system acts as a functional light-harvesting component. Conformational disorder breaks the conjugation in the polymer backbone, resulting in a chain composed of many chromophore units, whose relative energies depend on the segment lengths. Photoexcitation of the polyfluorene by a femtosecond laser pulse results in the excitation of polyfluorene, which then undergoes direct energy transfer to the pendant Ru(II) complexes, producing Ru(II)* excited states within 500 fs after photoexcitation. Femtosecond transient absorption data show the presence of electron transfer from PF* to Ru(II) to form charge-separated (CS) products within 1-2 ps. The decay of the oxidized and reduced products, PF(+•) and Ru(I), through back electron transfer are followed using picosecond transient absorption methods.
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Affiliation(s)
- Li Wang
- †Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Egle Puodziukynaite
- ‡Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Ryan P Vary
- †Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Erik M Grumstrup
- †Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Ryan M Walczak
- ‡Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Olga Y Zolotarskaya
- ‡Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611-7200, United States
| | - Kirk S Schanze
- ‡Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611-7200, United States
| | - John R Reynolds
- ‡Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611-7200, United States
- §School of Chemistry and Biochemistry, School of Materials Science and Engineering, Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - John M Papanikolas
- †Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
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Wilger DJ, Bettis SE, Materese CK, Minakova M, Papoian GA, Papanikolas JM, Waters ML. Tunable Energy Transfer Rates via Control of Primary, Secondary, and Tertiary Structure of a Coiled Coil Peptide Scaffold. Inorg Chem 2012; 51:11324-38. [DOI: 10.1021/ic300669t] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Dale J. Wilger
- Department
of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - Stephanie E. Bettis
- Department
of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - Christopher K. Materese
- Department
of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - Maria Minakova
- Department
of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - Garegin A. Papoian
- Department of Chemistry and
Biochemistry, University of Maryland, College
Park, Maryland 20742, United States
| | - John M. Papanikolas
- Department
of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
| | - Marcey L. Waters
- Department
of Chemistry, CB
3290, University of North Carolina, Chapel
Hill, North Carolina 27599, United States
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Miller SA, West BA, Curtis AC, Papanikolas JM, Moran AM. Communication: Uncovering molecule-TiO2 interactions with nonlinear spectroscopy. J Chem Phys 2011; 135:081101. [DOI: 10.1063/1.3631339] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- Stephen A. Miller
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Brantley A. West
- Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Anna C. Curtis
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - John M. Papanikolas
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Andrew M. Moran
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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Kent CA, Liu D, Ma L, Papanikolas JM, Meyer TJ, Lin W. Light Harvesting in Microscale Metal–Organic Frameworks by Energy Migration and Interfacial Electron Transfer Quenching. J Am Chem Soc 2011; 133:12940-3. [DOI: 10.1021/ja204214t] [Citation(s) in RCA: 211] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Caleb A. Kent
- Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Demin Liu
- Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Liqing Ma
- Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - John M. Papanikolas
- Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Thomas J. Meyer
- Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Wenbin Lin
- Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599, United States
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50
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Affiliation(s)
- Caleb A. Kent
- Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Brian P. Mehl
- Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Liqing Ma
- Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599
| | - John M. Papanikolas
- Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Thomas J. Meyer
- Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Wenbin Lin
- Department of Chemistry, CB#3290, University of North Carolina, Chapel Hill, North Carolina 27599
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