@article{djieutedjeu_makongo_rotaru_palasyuk_takas_zhou_ranmohotti_spinu_uher_poudeu_2011, title={Crystal structure, charge transport, and magnetic properties of MnSb(2)Se(4)}, number={26}, journal={European Journal of Inorganic Chemistry}, author={Djieutedjeu, H. and Makongo, J. P. A. and Rotaru, A. and Palasyuk, A. and Takas, N. J. and Zhou, X. Y. and Ranmohotti, K. G. S. and Spinu, L. and Uher, C. and Poudeu, P. F. P.}, year={2011}, pages={3969–3977} }
 @article{joshi_palasyuk_maggard_2011, title={Photoelectrochemical Investigation and Electronic Structure of a p-Type CuNbO3 Photocathode}, volume={115}, ISSN={["1932-7447"]}, DOI={10.1021/jp204631a}, abstractNote={A new p-type CuNbO3 photoelectrode was prepared on fluorine-doped tin oxide (FTO) glass and characterized by X-ray diffraction (XRD), UV–vis spectroscopy, and photoelectrochemical techniques. Solid-state syntheses yielded a red-colored CuNbO3 phase (space group: C2/m (No. 12), Z = 8, a = 9.525(1) A, b = 8.459(2) A, c = 6.793(1) A, β = 90.9(2)°) with a measured optical bandgap size of ∼2.0 eV. Phase-pure samples could be deposited and annealed on FTO slides at 400 °C under vacuum. Photoelectrochemical measurements showed the onset of a photocathodic current driven under visible-light irradiation and reaching incident-photon-to-current efficiencies exceeding ∼5%. The p-type CuNbO3 film also exhibits a stable photocurrent and notable resistance to photocorrosion, as shown by X-ray diffraction. Electronic structure calculations based on density functional theory reveal the visible-light absorption originates from a nearly direct bandgap transition owing primarily to copper-to-niobium (d10-to-d0) excitations. ...}, number={27}, journal={JOURNAL OF PHYSICAL CHEMISTRY C}, author={Joshi, Upendra A. and Palasyuk, Andriy M. and Maggard, Paul A.}, year={2011}, month={Jul}, pages={13534–13539} }
 @article{joshi_palasyuk_arney_maggard_2010, title={Semiconducting Oxides to Facilitate the Conversion of Solar Energy to Chemical Fuels}, volume={1}, ISSN={["1948-7185"]}, DOI={10.1021/jz100961d}, abstractNote={The rising significance of producing useful chemical fuels from sunlight has motivated an upsurge of photochemical research, as shown by the growing diversity of chromophores, redox catalysts, and reactivity studies. However, their synergistic integration within artificial photosynthetic systems requires shareable platforms. Early transition-metal oxides have exhibited effective chromophoric/electronic properties across many systems, which has enabled outstanding photocatalytic water splitting efficiencies, but only under ultraviolet irradiation. Semiconducting modifications of these oxides have been investigated that both extend their absorption deep into the visible region and also closely bracket the redox potentials for water splitting and carbon dioxide reduction. Their coupling to surface-anchored molecular catalysts in order to lower kinetic barriers and provide product selectivity is anticipated to lead to studies involving the dynamic interplay of photons, charge carriers, and catalyst turnover.}, number={18}, journal={JOURNAL OF PHYSICAL CHEMISTRY LETTERS}, author={Joshi, Upendra A. and Palasyuk, Andriy and Arney, David and Maggard, Paul A.}, year={2010}, month={Sep}, pages={2719–2726} }
 @article{palasyuk_palasyuk_maggard_2010, title={Site-Differentiated Solid Solution in (Na1-xCux)(2)Ta4O11 and Its Electronic Structure and Optical Properties}, volume={49}, ISSN={["1520-510X"]}, DOI={10.1021/ic101529n}, abstractNote={The (Na(1-x)Cu(x))(2)Ta(4)O(11) (0 ≤ x ≤ 0.78) solid-solution was synthesized within evacuated fused-silica vessels and characterized by powder X-ray diffraction techniques (space group: R3c (#167), Z = 6, a = 6.2061(2)-6.2131(2) Å, c = 36.712(1)-36.861(1) Å, for x = 0.37, 0.57, and 0.78). The structure consists of single layers of TaO(7) pentagonal bipyramids as well as layers of isolated TaO(6) octahedra surrounded by Na(+) and Cu(+) cations. Full-profile Rietveld refinements revealed a site-differentiated substitution of Na(+) cations located in the 12c (Wyckoff) crystallographic site for Cu(+) cations in the 18d crystallographic site. This site differentiation is driven by the linear coordination geometry afforded at the Cu(+) site compared to the distorted seven-coordinate geometry of the Na(+) site. Compositions more Cu-rich than x ~ 0.78, that is, closer to "Cu(2)Ta(4)O(11)", could not be synthesized owing to the destabilizing Na(+)/Cu(+) vacancies that increase with x up to the highest attainable value of ~26%. The UV-vis diffuse reflectance spectra show a significant red-shift of the bandgap size from ~4.0 eV to ~2.65 eV with increasing Cu(+) content across the series. Electronic structure calculations using the TB-LMTO-ASA approach show that the reduction in bandgap size arises from the introduction of Cu 3d(10) orbitals and the formation of a new higher-energy valence band. A direct bandgap transition emerges at k = Γ that is derived from the filled Cu 3d(10) and the empty Ta 5d(0) orbitals, including a small amount of mixing with the O 2p orbitals. The resulting conduction and valence band energies are determined to favorably bracket the redox potentials for water reduction and oxidation, meeting the thermodynamic requirement for photocatalytic water-splitting reactions.}, number={22}, journal={INORGANIC CHEMISTRY}, author={Palasyuk, Olena and Palasyuk, Andriy and Maggard, Paul A.}, year={2010}, month={Nov}, pages={10571–10578} }
 @article{palasyuk_maggard_2010, title={Structural modification and optical reflectivity of new gold-indide intermetallic compounds}, volume={491}, ISSN={["1873-4669"]}, DOI={10.1016/j.jallcom.2009.10.152}, abstractNote={The gold–indide SrAu3.36(2)In4.64 contains a novel 3D Au/In network, which can be described in terms of complex ∞3[Au,In]82− polyanions with strontium atoms filling hexagonal cages that are part of highly condensed infinite channels. This new intermetallic compound represents a small decrease in the indium content, i.e., as compared to SrAu3.76(4)In4.24, and results in a significant orthorhombic to monoclinic structural transformation. Electronic structure calculations by Linear Muffin-Tin-Orbital (LMTO) methods show that Au–In interactions are predominant in its structural stabilization. UV–vis measurements show a generally lower reflectivity and higher absorption, as compared to elemental Au.}, number={1-2}, journal={JOURNAL OF ALLOYS AND COMPOUNDS}, author={Palasyuk, A. and Maggard, Paul A.}, year={2010}, month={Feb}, pages={81–84} }
 @article{palasyuk_palasyuk_maggard_2010, title={Syntheses, optical properties and electronic structures of copper(I) tantalates: Cu5Ta11O30 and Cu3Ta7O19}, volume={183}, ISSN={["1095-726X"]}, DOI={10.1016/j.jssc.2010.01.030}, abstractNote={Two copper tantalates, Cu5Ta11O30 (1) and Cu3Ta7O19 (2), were synthesized by solid-state and flux synthetic methods, respectively. A synthetic route yielding 2 in high purity was found using a CuCl flux at 800oC and its structure was characterized using powder X-ray diffraction (XRD) data (P63/m (no. 176), Z=2, a=6.2278(1) Å, and c=20.1467(3) Å). The solid-state synthesis of 1 was performed using excess Cu2O that helped to facilitate the growth of single crystals and their characterization by XRD (P6¯2c (no. 190), Z=2, a=6.2252(1) Å, and c=32.516(1) Å). The atomic structures of both copper tantalates consist of alternating single and double layers of TaO7 pentagonal bipyramids that are bridged by a single layer of isolated TaO6 octahedra and linearly-coordinated Cu+. Measured optical bandgap sizes of ∼2.59 and ∼2.47 eV for 1 and 2 were located well within visible-light energies and were consistent with their orange–yellow colours. Each also exhibits optical absorption coefficients at the band edge of ∼700 and ∼275 cm−1, respectively, and which were significantly smaller than that for NaTaO3 of ∼1450 cm−1. Results of LMTO calculations indicate that their visible-light absorption is attributable mainly to indirect bandgap transitions between Cu 3d10 and Ta 5d0 orbitals within the TaO7 pentagonal bipyramids.}, number={4}, journal={JOURNAL OF SOLID STATE CHEMISTRY}, author={Palasyuk, Olena and Palasyuk, Andriy and Maggard, Paul A.}, year={2010}, month={Apr}, pages={814–822} }