@article{hewitt_boltersdorf_maggard_dougherty_2017, title={Recovery of of the bulk-like electronic structure of manganese phthalocyanine beyond the first monolayer on Bi2Te3}, volume={662}, ISSN={["1879-2758"]}, DOI={10.1016/j.susc.2017.03.014}, abstractNote={The evolution of electronic structure of manganese phthalocyanine on Bi2Te3 shows a transition to a bulk-like aspect abruptly after completion of the first layer. This allows the inference that, in the first layer, there is charge transfer and electronic hybridization involving the occupied Mn-derived d orbitals of the molecule into the conduction band of the substrate. The charge transfer coupling is seen using angle-resolved ultraviolet photoelectron spectroscopy by monitoring the evolution of work function and band structure with increasing molecular film thickness. The electronic structure in the second layer is more bulk-like as indicated by the reappearance of well-known low energy d orbitals that were depopulated in the first layer. Scanning tunneling microscopy shows that the transition to bulk like behavior is also reflected in film structure as a transition from a unique disordered monolayer to a locally ordered and dense second layer. These observations are relevant to ongoing efforts to control topological insulator interfaces especially for spintronics applications.}, journal={SURFACE SCIENCE}, author={Hewitt, A. S. and Boltersdorf, J. and Maggard, P. A. and Dougherty, D. B.}, year={2017}, month={Aug}, pages={87–92} }
 @article{boltersdorf_sullivan_shelton_wu_gray_zoellner_osterloh_maggard_2016, title={Flux Synthesis, Optical and Photocatalytic Properties of n-type Sn2TiO4: Hydrogen and Oxygen Evolution under Visible Light}, volume={28}, ISSN={["1520-5002"]}, DOI={10.1021/acs.chemmater.6b02003}, abstractNote={The n-type Sn2TiO4 phase was synthesized using flux methods and found to have one of the smallest visible-light bandgap sizes known that also maintains suitable conduction and valence band energies for driving photocatalytic water-splitting reactions. The Sn2TiO4 phase was synthesized using either a SnCl2 flux or a SnCl2/SnF2 peritectic flux in a 2:1 flux-to-precursor ratio heated at 600 and 400 °C for 24 h, respectively. The two types of salt fluxes resulted in large rod-shaped particles at 600 °C and smaller tetragonal prism-shaped particles at 400 °C. Surface photovoltage spectroscopy measurements produced a negative photovoltage under illumination >1.50 eV, which confirmed electrons as the majority charge carriers and ∼1.50 eV as the effective band gap. Mott–Schottky measurements at pH 9.0 showed the conduction (−0.54 V vs NHE) and valence band (+1.01 V vs NHE) positions meet the critical thermodynamic requirements for total water splitting. The Sn2TiO4 particles were deposited and annealed as polycry...}, number={24}, journal={CHEMISTRY OF MATERIALS}, author={Boltersdorf, Jonathan and Sullivan, Ian and Shelton, Timothy L. and Wu, Zongkai and Gray, Matthew and Zoellner, Brandon and Osterloh, Frank E. and Maggard, Paul A.}, year={2016}, month={Dec}, pages={8876–8889} }
 @article{boltersdorf_zoellner_fancher_jones_maggard_2016, title={Single- and Double-Site Substitutions in Mixed-Metal Oxides: Adjusting the Band Edges Toward the Water Redox Couples}, volume={120}, ISSN={["1932-7455"]}, DOI={10.1021/acs.jpcc.6b05758}, abstractNote={New mixed-metal oxide solid solutions, i.e., the single-metal substituted Na2Ta4–yNbyO11 (0 ≤ y ≤ 4) and the double-metal substituted Na2–2xSnxTa4–yNbyO11 (0 ≤ y ≤ 4; 0 ≤ x ≤ 0.35), were investigated and used to probe the impact of composition on their crystalline structures, optical band gaps, band energies, and photocatalytic properties. The Na2Ta4O11 (y = 1) phase was prepared by flux-mediated synthesis, while the members of the Na2Ta4–yNbyO11 solid solution (1 ≤ y ≤ 4) were prepared by traditional high-temperature reactions. The Sn(II)-containing Na2–2xSnxTa4–yNbyO11 (0 ≤ y ≤ 4) solid solutions were prepared by flux-mediated ion-exchange reactions of the Na2Ta4–yNbyO11 solid solutions within a SnCl2 flux. The crystalline structures of both solid solutions are based on the parent Na2B4O11 (B = Nb, Ta) phases and consist of layers of edge-shared BO7 pentagonal bipyramids that alternate with layers of isolated BO6 octahedra surrounded by Na(I) cations. Rietveld refinements of the Na2Ta4–yNbyO11 solid sol...}, number={34}, journal={Journal of Physical Chemistry C}, author={Boltersdorf, J. and Zoellner, B. and Fancher, C. and Jones, J. and Maggard, P.A.}, year={2016}, month={Aug}, pages={19175–19188} }
 @article{boltersdorf_king_maggard_2015, title={Flux-mediated crystal growth of metal oxides: synthetic tunability of particle morphologies, sizes, and surface features for photocatalysis research}, volume={17}, ISSN={["1466-8033"]}, DOI={10.1039/c4ce01587h}, abstractNote={Flux crystal growth of mixed-metal oxide photocatalysts with (A) rod- and (B) platelet-shaped morphologies grown under varied flux conditions.}, number={11}, journal={CRYSTENGCOMM}, author={Boltersdorf, Jonathan and King, Nacole and Maggard, Paul A.}, year={2015}, pages={2225–2241} }
 @article{boltersdorf_maggard_2015, title={Structural and electronic investigations of PbTa4O11 and BiTa7O19 constructed from alpha-U3O8 types of layers}, volume={229}, ISSN={["1095-726X"]}, DOI={10.1016/j.jssc.2015.06.019}, abstractNote={The PbTa4O11 and BiTa7O19 phases were prepared by ion-exchange and solid-state methods, respectively, and their structures were characterized by neutron time-of-flight diffraction and Rietveld refinement methods (PbTa4O11, R3 (No. 146), a=6.23700(2) Å, c=36.8613(1) Å; BiTa7O19, P6¯c2 (No. 188), a=6.2197(2) Å, c=20.02981(9) Å). Their structures are comprised of layers of TaO6 octahedra surrounded by three 7-coordinate Pb(II) cations or two 8-coordinate Bi(III) cations. These layers alternate down the c-axis with α-U3O8 types of single and double TaO7 pentagonal bipyramid layers. In contrast to earlier studies, both phases are found to crystallize in noncentrosymmetric structures. Symmetry-lowering structural distortions within PbTa4O11, i.e. R3¯c→R3, are found to be a result of the displacement of the Ta atoms within the TaO7 and TaO6 polyhedra, towards the apical and facial oxygen atoms, respectively. In BiTa7O19, relatively lower reaction temperatures leads to an ordering of the Bi/Ta cations within a lower-symmetry structure, i.e., P63/mcm→P6¯c2. In the absence of Bi/Ta site disorder, the Ta–O–Ta bond angles decrease and the Ta–O bond distances increase within the TaO7 double layers. Scanning electron microscopy images reveal two particle morphologies for PbTa4O11, hexagonal rods and finer irregularly-shaped particles, while BiTa7O19 forms as aggregates of irregularly-shaped particles. Electronic-structure calculations confirm the highest-energy valence band states are comprised of O 2p-orbitals and the respective Pb 6s-orbital and Bi 6s-orbital contributions. The lowest-energy conduction band states are composed of Ta 5d-orbital contributions that are delocalized over the TaO6 octahedra and layers of TaO7 pentagonal bipyramids. The symmetry-lowering distortions in the PbTa4O11 structure, and the resulting effects on its electronic structure, lead to its relatively higher photocatalytic activity compared to similar structures without these distortions.}, journal={JOURNAL OF SOLID STATE CHEMISTRY}, author={Boltersdorf, Jonathan and Maggard, Paul A.}, year={2015}, month={Sep}, pages={310–321} }
 @article{carpenter_scholle_sadeghifar_francis_boltersdorf_weare_argyropoulos_maggard_ghiladi_2015, title={Synthesis, Characterization, and Antimicrobial Efficacy of Photomicrobicidal Cellulose Paper}, volume={16}, ISSN={["1526-4602"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84938937944&partnerID=MN8TOARS}, DOI={10.1021/acs.biomac.5b00758}, abstractNote={Toward our goal of scalable, antimicrobial materials based on photodynamic inactivation, paper sheets comprised of photosensitizer-conjugated cellulose fibers were prepared using porphyrin and BODIPY photosensitizers, and characterized by spectroscopic (infrared, UV-vis diffuse reflectance, inductively coupled plasma optical emission) and physical (gel permeation chromatography, elemental, and thermal gravimetric analyses) methods. Antibacterial efficacy was evaluated against Staphylococcus aureus (ATCC-2913), vancomycin-resistant Enterococcus faecium (ATCC-2320), Acinetobacter baumannii (ATCC-19606), Pseudomonas aeruginosa (ATCC-9027), and Klebsiella pneumoniae (ATCC-2146). Our best results were achieved with a cationic porphyrin-paper conjugate, Por((+))-paper, with inactivation upon illumination (30 min, 65 ± 5 mW/cm(2), 400-700 nm) of all bacterial strains studied by 99.99+% (4 log units), regardless of taxonomic classification. Por((+))-paper also inactivated dengue-1 virus (>99.995%), influenza A (∼ 99.5%), and human adenovirus-5 (∼ 99%). These results demonstrate the potential of cellulose materials to serve as scalable scaffolds for anti-infective or self-sterilizing materials against both bacteria and viruses when employing a photodynamic inactivation mode of action.}, number={8}, journal={BIOMACROMOLECULES}, author={Carpenter, Bradley L. and Scholle, Frank and Sadeghifar, Hasan and Francis, Aaron J. and Boltersdorf, Jonathan and Weare, Walter W. and Argyropoulos, Dimitris S. and Maggard, Paul A. and Ghiladi, Reza A.}, year={2015}, month={Aug}, pages={2482–2492} }
 @article{hewitt_wang_boltersdorf_maggard_dougherty_2014, title={Coexisting Bi and Se surface terminations of cleaved Bi2Se3 single crystals}, volume={32}, number={4}, journal={Journal of Vacuum Science & Technology. B, Microelectronics and Nanometer Structures}, author={Hewitt, A. S. and Wang, J. Y. and Boltersdorf, J. and Maggard, P. A. and Dougherty, D. B.}, year={2014} }
 @article{xu_hewitt_wang_guan_boltersdorf_maggard_dougherty_gundogdu_2014, title={Intrinsic and extrinsic effects on the electrostatic field at the surface of Bi2Se3}, volume={116}, number={4}, journal={Journal of Applied Physics}, author={Xu, C. and Hewitt, A. and Wang, J. Y. and Guan, T. S. and Boltersdorf, J. and Maggard, P. A. and Dougherty, D. B. and Gundogdu, K.}, year={2014} }
 @article{wang_hewitt_kumar_boltersdorf_guan_hunte_maggard_brom_redwing_dougherty_2014, title={Molecular Doping Control at a Topological Insulator Surface: F-4-TCNQ on Bi2Se3}, volume={118}, ISSN={["1932-7447"]}, DOI={10.1021/jp412690h}, abstractNote={Recent electrical measurements have accessed transport in the topological surface state band of thin exfoliated samples of Bi2Se3 by removing the bulk n-type doping by contact with thin films of the molecular acceptor F4-TCNQ. Here we report on the film growth and interfacial electronic characterization of F4-TCNQ grown on Bi2Se3. Atomic force microscopy shows wetting layer formation followed by 3D island growth. X-ray photoelectron spectroscopy is consistent with this picture and also shows that charge transferred to the molecular layer is localized on nitrogen atoms. Ultraviolet photoelectron spectroscopy shows a work function increase and an upward shift of the valence band edge that suggest significant reduction in carrier density at the Bi2Se3 surface.}, number={27}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, author={Wang, J. and Hewitt, A. S. and Kumar, R. and Boltersdorf, J. and Guan, T. and Hunte, F. and Maggard, P. A. and Brom, J. E. and Redwing, J. M. and Dougherty, D. B.}, year={2014}, month={Jul}, pages={14860–14865} }
 @article{boltersdorf_maggard_2013, title={Silver Exchange of Layered Metal Oxides and Their Photocatalytic Activities}, volume={3}, ISSN={2155-5435 2155-5435}, url={http://dx.doi.org/10.1021/CS400466B}, DOI={10.1021/cs400466b}, abstractNote={Layered Dion–Jacobson phases RbLaNb2O7 and RbA2Nb3O10 (A = Ca, Sr) and the Ruddlesden–Popper phase Rb2La2Ti3O10 were prepared by solid-state methods at a reaction time of 50 h and a temperature of 1100 °C. The products were silver-exchanged within a AgNO3 flux at a reaction time of 24 h and a temperature of 250 °C. Substitution of silver cations into the interlayer spacing of the layered structures is found to decrease the optical bandgap sizes on average by ∼0.5 to ∼1.0 eV. The products were found by scanning electron microscopy (SEM) to exhibit irregularly shaped platelet morphologies with an average size of ∼1–5 μm across their lateral dimensions and stepped edges ranging from ∼20 to ∼300 nm in height. Significant increases in photocatalytic hydrogen production rates for all silver-exchanged products were observed. The silver-exchanged RbA2Nb3O10 layered structures exhibited the highest photocatalytic hydrogen formation rates under ultraviolet and visible irradiation (∼13,616 μmol H2·g–1·h–1). These ra...}, number={11}, journal={ACS Catalysis}, publisher={American Chemical Society (ACS)}, author={Boltersdorf, Jonathan and Maggard, Paul A.}, year={2013}, month={Oct}, pages={2547–2555} }
 @article{boltersdorf_wong_maggard_2013, title={Synthesis and Optical Properties of Ag(I), Pb(II), and Bi(III) Tantalate-Based Photocatalysts}, volume={3}, ISSN={["2155-5435"]}, DOI={10.1021/cs400707x}, abstractNote={The Ag(I) and Bi(III) tantalates Ag2Ta4O11, BiTa7O19, and Bi7Ta3O18 were prepared by solid-state methods at 1000 °C for 24–48 h. The Pb(II)-containing tantalate PbTa2O6 was prepared at 1100 °C for 24 h, whereas Pb3Ta4O13 and PbTa4O11 were synthesized from a reaction of A2Ta4O11 (A = Na, Ag) precursors with a PbCl2 flux (at 1:1, 5:1, and 10:1 molar ratios) at 700 °C from 24 to 96 h. The PbTa2O6, Pb3Ta4O13, and Bi7Ta3O18 structures consist of TaO6 layers and TaO6 chains/rings with Pb(II) ions located within the cavities. The structures of Ag2Ta4O11, PbTa4O11, and BiTa7O19 consist of layers of TaO7 pentagonal bipyramids that alternate with Ag(I), Pb(II), and Bi(III) cations, respectively. UV–vis diffuse reflectance data were used to measure bandgap sizes for Ag2Ta4O11 (∼3.9 eV), PbTa4O11 (∼3.8–3.95 eV), Pb3Ta4O13 (∼3.0 eV), PbTa2O6 (∼3.6 eV), BiTa7O19 (∼3.6 eV), and Bi7Ta3O18 (∼2.75 eV). A decrease in the band gap was observed with an increase in the Pb(II) or Bi(III) content. Photocatalytic activities of th...}, number={12}, journal={ACS CATALYSIS}, author={Boltersdorf, Jonathan and Wong, Tricia and Maggard, Paul A.}, year={2013}, month={Dec}, pages={2943–2953} }
 @article{arney_fuoco_boltersdorf_maggard_2013, title={Flux Synthesis of Na2Ca2Nb4O13: The Influence of Particle Shapes, Surface Features, and Surface Areas on Photocatalytic Hydrogen Production}, volume={96}, ISSN={["0002-7820"]}, DOI={10.1111/jace.12122}, abstractNote={The layered perovskite (n = 4) Ruddlesden‐Popper phase Na2Ca2Nb4O13 was prepared within molten NaCl and Na2SO4 fluxes, yielding either rod‐shaped or platelet‐shaped particles, respectively. The flux‐to‐reactant molar ratios of 5:1 or 20:1 were found to significantly influence particle sizes and surface areas, while still maintaining the overall particle shapes. Measured surface areas of flux‐prepared Na2Ca2Nb4O13 particles ranged from ∼0.36 to 4.6 m2/g, with the highest surface areas obtained using a 5:1 (NaCl‐to‐Na2Ca2Nb4O13) molar ratio. All samples exhibited a bandgap size of ∼3.3 eV, as determined by UV–Vis diffuse reflectance measurements. Photocatalytic rates for hydrogen production under ultraviolet light for platinized Na2Ca2Nb4O13 particles in an aqueous methanol solution ranged from ∼230 to 1355 μmol H2 g−1 h−1 when using the photochemical deposition (PCD) method of platinization, and ∼113–1099 μmol H2 g−1 h−1 when using the incipient wetness impregnation (IWI) method of platinization. The higher photocatalytic rates were obtained for the rod‐shaped particles with the highest surface areas, with an apparent quantum yield (AQY) measured at ∼6.5% at 350 nm. For the platelet‐shaped particles, the higher photocatalytic rates were observed for the sample with the lowest surface area but the largest concentration of stepped edges and grooves observed at the particle surfaces. The latter origin of the photocatalytic activity is confirmed by the significant enhancement of the photocatalytic rates by the PCD method that allows for the preferential deposition of the surface Pt cocatalyst islands at the stepped edges and grooves, while the photocatalytic enhancement is much smaller when using the more general IWI platinization method.}, number={4}, journal={JOURNAL OF THE AMERICAN CERAMIC SOCIETY}, author={Arney, David and Fuoco, Lindsay and Boltersdorf, Jonathan and Maggard, Paul A.}, year={2013}, month={Apr}, pages={1158–1162} }