Single Crystalline Hematite Films for Solar Water Splitting: Ti-Doping and Thickness Effects
| Autor: | Maxime Rioult, D. Stanescu, Hélène Magnan, Antoine Barbier |
|---|---|
| Přispěvatelé: | Laboratoire Nano-Magnétisme et Oxydes (LNO), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay |
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
[PHYS]Physics [physics]
Materials science Hydrogen business.industry Doping Analytical chemistry chemistry.chemical_element Hematite Epitaxy Surfaces Coatings and Films Electronic Optical and Magnetic Materials Dielectric spectroscopy General Energy Optics chemistry visual_art visual_art.visual_art_medium Water splitting Physical and Theoretical Chemistry Thin film business Molecular beam epitaxy |
| Zdroj: | Journal of Physical Chemistry C Journal of Physical Chemistry C, American Chemical Society, 2014, 118, pp.3007-3014. ⟨10.1021/jp500290j⟩ Journal of Physical Chemistry C, 2014, 118, pp.3007-3014. ⟨10.1021/jp500290j⟩ |
| ISSN: | 1932-7447 1932-7455 |
| Popis: | International audience; Undoped and Ti-doped (2 at. %) epitaxial hematite thin films, in the thickness range 5–50 nm, were grown by atomic oxygen assisted molecular beam epitaxy (AO-MBE) on Pt(111) substrates in the framework of hydrogen harvesting from sunlight-induced water splitting. Such single crystalline samples are suitable model systems to study thickness and doping effects on the photoelectrochemical properties; we demonstrate that they also allow disentangling intrinsic transport properties from mingled overall properties due to the usually unknown contributions from morphology or crystalline structure defects. From their photoelectrochemical characteristics (I(V) curves, incident photon to current efficiency measurements, and electrochemical impedance spectroscopy), we evidence the existence of an optimum layer thickness, which is higher for Ti-doped samples (30 nm) as compared to undoped ones (20 nm). Our results suggest that this effect is due to an increase of the carrier concentration combined with higher carriers’ diffusion lengths in the doped samples stressing intrinsic modifications of the hematite layer upon titanium doping that cannot be accounted for by simple structural or electronic structure changes. |
| Databáze: | OpenAIRE |
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