A5086768575- Porphyrin and Phthalocyanine Chemistry
- TiO2 Photocatalysis and Solar Cells
- Photochemistry and Electron Transfer Studies
- Electrocatalysts for Energy Conversion
- Analytical Chemistry and Sensors
- Advanced Photocatalysis Techniques
- Electrochemical Analysis and Applications
- Spectroscopy and Quantum Chemical Studies
- Quantum Dots Synthesis And Properties
- Molecular Junctions and Nanostructures
- Copper-based nanomaterials and applications
- Conducting polymers and applications
- Luminescence and Fluorescent Materials
- Polyoxometalates: Synthesis and Applications
- Electrochemical sensors and biosensors
- Advanced Nanomaterials in Catalysis
- Oxidative Organic Chemistry Reactions
- Lignin and Wood Chemistry
- Organic Electronics and Photovoltaics
- Organic Light-Emitting Diodes Research
- Polymer Surface Interaction Studies
- Advanced battery technologies research
- Polymer composites and self-healing
- ZnO doping and properties
- biodegradable polymer synthesis and properties
University of North Carolina at Chapel Hill
2014-2021
Communities In Schools of Orange County
2015
North Dakota State University
2013
Interfacial electron transfer at titanium dioxide (TiO2) is investigated for a series of surface bound ruthenium-polypyridyl dyes whose metal-to-ligand charge-transfer state (MLCT) energetics are tuned through chemical modification. The 12 complexes the form Ru(II)(bpy-A)(L)2(2+), where bpy-A bipyridine ligand functionalized with phosphonate groups attachment to TiO2. Functionalization ancillary ligands (L) enables potential excited Ru(III/)* couple, E(+/)*, in 0.1 M perchloric acid...
Interfacial electron transfer to and from conductive Sn-doped In2O3 (ITO) nanoparticles (NPs) in mesoporous thin films has been investigated by transient absorption measurements using surface-bound [Ru(II)(bpy)2(dcb)](2+) (bpy is 2,2'-bipyridyl dcb 4,4'-(COOH)2-2,2'-bipyridyl). Metal-to-ligand charge excitation 0.1 M LiClO4 MeCN results efficient injection into the ITO NPs on picosecond time scale followed back nanosecond scale. Rates of are dependent thermal annealing conditions with rate...
Photoinduced, interfacial electron injection and back transfer between surface-bound [Ru(II)(bpy)2(4,4'-(PO3H2)2-bpy)](2+) degenerately doped In2O3:Sn nanoparticles, present in mesoporous thin films (nanoITO), have been studied as a function of applied external bias. Due to the metallic behavior nanoITO films, application an bias was used vary Fermi level oxide and, with it, driving force for (ΔG(o)'). By controlling bias, ΔG(o)' varied from 0 -1.8 eV -0.3 -1.3 transfer. Analysis...
Layer-by-Layer (LbL) polyelectrolyte self-assembly occurs by the alternate exposure of a substrate to solutions oppositely charged polyelectrolytes or polyions. Here, we report application LbL construct chromophore–catalyst assemblies consisting cationic polystyrene-based Ru polychromophore (PS-Ru) and [Ru(tpy)(2-pyridyl-N-methylbenzimidazole) (OH2)]2+ water oxidation catalyst (RuC), codeposited with poly(acrylic acid) (PAA) as an inert polyanion. These are deposited onto planar indium tin...
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). contains a phosphonic acid group for anchoring to TiO2 photoanode under conditions, terthiophene fragment light absorption electron injection into TiO2, terminal trpy the construction of assemblies comprising molecular oxidation catalyst. At photoanode, displays...
ConspectusThe use of sunlight to make chemical fuels (i.e., solar fuels) is an attractive approach in the quest develop sustainable energy sources. Using nature as a guide, assemblies for artificial photosynthesis will need perform multiple functions. They be able harvest light across broad region spectrum, transport excited-state charge-separation sites, and then store redox equivalents catalytic reactions that produce fuels. This multifunctional behavior require assimilation components...
Degenerately doped In2O3:Sn semiconductor nanoparticles (nanoITO) have been used to study the photoinduced interfacial electron-transfer reactivity of surface-bound [Ru(II)(bpy)2(4,4'-(PO3H2)2-bpy)](2+) (RuP(2+)) molecules as a function driving force over range 1.8 eV. The metallic properties ITO nanoparticles, present within an interconnected mesoporous film, allowed for be tuned by controlling their Fermi level with external bias while optical transparency transient absorption spectroscopy...
This paper describes the photophysical and photoelectrochemical characterization of a light harvesting polychromophore array featuring polyfluorene backbone with covalently attached Ru(II) polypyridyl complexes (PF-Ru-A), adsorbed on surface mesostructured TiO2 (PF-Ru-A//TiO2). The polymer is characterized by transmission electron microscopy (TEM), scanning (SEM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, providing evidence for morphology mode binding....
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 TiO 2 films (TiO //PS‐Ru‐A). Studies of the resulting //PS‐Ru‐A carried out by transmission electron microscopy (TEM), scanning (SEM), atomic force (AFM) confirmed that carboxylated from PS‐Ru‐A led to surface immobilization on film....
A series of polystyrene-based light harvesting polymers featuring pendant polypyridyl ruthenium complexes has been synthesized.
Ultrafast energy and electron transfer (EnT ET, respectively) are characterized in a light-harvesting assembly based on π-conjugated polymer (poly(fluorene)) functionalized with broadly absorbing pendant organic isoindigo (iI) chromophores using combination of femtosecond transient absorption spectroscopy large-scale computer simulation. Photoexcitation the leads to near-unity quenching excitation through EnT ET iI pendants. The excited pendants formed by rapidly relax within 30 ps, whereas...
Photoinduced electron injection, intra-assembly transfer, and back-electron transfer are investigated in a single-site molecular assembly formed by covalently linking phosphonated terthiophene (T3) chromophore to Ru(terpyridine)(bipyridine)(L)2+ (L = MeCN or H2O) water oxidation catalyst adsorbed onto mesoporous metal-oxide (MOx) film. Density functional theory calculations of the T3-trpy-Ru-L indicate that components strongly coupled with enhanced low-energy absorptions owing presence an...
ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionNEXTORIGINAL ARTICLEThis notice is a correctionLight-Driven Water Oxidation Using Polyelectrolyte Layer-by-Layer Chromophore–Catalyst AssembliesGyu Leem, Benjamin D. Sherman, Alex J. Burnett, Zachary A. Morseth, Kyung-Ryang Wee, Leila Alibabaei, John M. Papanikolas, Thomas Meyer, and Kirk S. Schanze*Cite this: ACS Energy Lett. 2016, 1, 6, 1118Publication Date (Web):November 9, 2016Publication History Published online9 November 2016Published...
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 combination time-resolved emission spectroscopy coarse-grained molecular dynamics (CG MD). Photoexcitation Ru chromophore initiates Dexter-style hopping along isoenergetic followed by sensitization lower-energy Os trap. While we can determine total rate within an ensemble solvated PF-RuOs from time-dependent Os* spectra,...