skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


  • NSF Public Access
  • Search Results
  • Moderate temperature sulfurization and selenization of highly stable metal oxides: an opportunity for chalcogenide perovskites
Title: Moderate temperature sulfurization and selenization of highly stable metal oxides: an opportunity for chalcogenide perovskites
Oxide perovskites would provide a convenient precursor for the synthesis of chalcogenide perovskites. However, the stability of oxide perovskites means that there is no driving force for sulfurization or selenization with conventional chalcogen sources. In this work, we show that sulfurization and selenization of highly stable early transition metal oxides are possible by heating in the presence of HfH2 and S or Se, thereby creating HfS3 or HfSe3 as an oxygen sink and producing an oxygen shuttle in the form of H2O/H2S or H2O/H2Se. The conversion of ZrO2 into ZrS3 or ZrSe3 is supported with thermodynamic calculations and demonstrated experimentally as a proof-of-concept. Subsequently, we demonstrate that BaZrO3 can be converted to BaZrS3 at 575 °C, several hundred degrees below previous methods relying on conventional sulfur sources.  more » « less
Award ID(s):
1855882
PAR ID:
10530804
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
Journal of Materials Chemistry C
Date Published:
Journal Name:
Journal of Materials Chemistry C
Volume:
11
Issue:
45
ISSN:
2050-7526
Page Range / eLocation ID:
15817 to 15823
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; ; ; et al (, Journal of Materials Research)
    Abstract Chalcogenide perovskites, particularly BaZrS3, hold promise for optoelectronic devices owing to their exceptional light absorption and inherent stability. However, thin films obtained at lower processing temperatures typically result in small grain sizes and inferior transport properties. Here we introduce an approach employing co-sputtering elemental Ba and Zr targets followed by CS2sulfurization, with a judiciously applied NaF capping layer. NaF acts as a flux agent during sulfurization, leading to marked increase in grain size and improved crystallinity. This process results in near-stoichiometric films with enhanced photoresponse. Terahertz spectroscopy further reveals a carrier mobility more than two orders of magnitude higher than those obtained from field-effect transistor measurements, suggesting that bulk transport is limited by grain boundary scattering. Our results demonstrate flux-assisted sulfurization as an effective strategy to improve the crystallinity of chalcogenide perovskite thin films for optoelectronic applications. Graphical abstract 
    more » « less
  2. ; ; ; ; ; ; ; ; ; ; et al (, Angewandte Chemie International Edition)
    Abstract Chalcogenide perovskites have garnered interest for applications in semiconductor devices due to their excellent predicted optoelectronic properties and stability. However, high synthesis temperatures have historically made these materials incompatible with the creation of photovoltaic devices. Here, we demonstrate the solution processed synthesis of luminescent BaZrS3and BaHfS3chalcogenide perovskite films using single‐phase molecular precursors at sulfurization temperatures of 575 °C and sulfurization times as short as one hour. These molecular precursor inks were synthesized using known carbon disulfide insertion chemistry to create Group 4 metal dithiocarbamates, and this chemistry was extended to create species, such as barium dithiocarboxylates, that have never been reported before. These findings, with added future research, have the potential to yield fully solution processed thin films of chalcogenide perovskites for various optoelectronic applications. 
    more » « less
  3. ; ; ; ; ; ; ; ; ; (, Journal of Materials Chemistry A)
    Electron doping in perovskites is an effective approach to design and tailor the structure and property of materials. In A 2 BB′O 6−δ -type double perovskites, B-site cation order can be tunable by A-site modification, potentially leading to significant effect on the oxygen nonstoichiometry of the compounds. La 3+ -doped Sr 2 FeMoO 6−δ (Sr 2−x La x FeMoO 6−δ , SLFM with 0 ≤ x ≤ 1) double perovskites have been designed and characterized systematically in this study as anode materials for solid oxide fuel cells. Rietveld refinement of powder X-ray diffraction reveals a crystalline symmetry transition of SLFM from tetragonal to orthorhombic with the increase of La content, driven by the extra electron onto the antibonding orbitals of e g and t 2g of Fe/Mo cations. An increase in Fe/Mo anti-site defect accompanies this phase transition. Solid oxide fuel cells incorporating the Sr 1.8 La 0.2 FeMoO 6−δ (SLFM2) anode demonstrate impressive power outputs and stable performance under direct CH 4 operation because of its altered electronic structure, desired oxygen vacancy concentration and enhanced reducibility. Density functional theory plus U correction calculations provide an insight into how La doping affects the Fe/Mo anti-site defects and consequently the oxygen transport dynamics. 
    more » « less
  4. ; ; ; ; ; ; ; (, National Science Review)
    Abstract Understanding the mineralogy of the Earth's interior is a prerequisite for unravelling the evolution and dynamics of our planet. Here, we conducted high pressure-temperature experiments mimicking the conditions of the deep lower mantle (DLM, 1800–2890 km in depth) and observed surprising mineralogical transformations in the presence of water. Ferropericlase, (Mg, Fe)O, which is the most abundant oxide mineral in Earth, reacts with H2O to form a previously unknown (Mg, Fe)O2Hx (x≤1) phase. The (Mg, Fe)O2Hx has the pyrite structure and it coexists with the dominant silicate phases, bridgmanite and post-perovskite. Depending on Mg content and geotherm temperatures, the transformation may occur at 1800 km for (Mg0.6Fe0.4)O or beyond 2300 km for (Mg0.7Fe0.3)O. The (Mg, Fe)O2Hx is an oxygen excess phase that stores an excessive amount of oxygen beyond the charge balance of maximum cation valences (Mg2+, Fe3+, and H+). This important phase has a number of far-reaching implications including the extreme redox inhomogeneity, deep-oxygen reservoirs in the DLM, and an internal source for modulating oxygen in the atmosphere. 
    more » « less
  5. ; ; ; ; ; ; ; ; (, ACS Applied Materials & Interfaces)
    Antimony selenide (Sb2Se3) is a promising material for solar energy conversion due to its low toxicity, high stability, and excellent light absorption capabilities. However, Sb2Se3 films produced via physical vapor deposition often exhibit Se-deficient surfaces, which result in a high carrier recombination and poor device performance. The conventional selenization process was used to address selenium loss in Sb2Se3 solar cells with a substrate configuration. However, this traditional selenization method is not suitable for superstrated Sb2Se3 devices with the window layer buried underneath the Sb2Se3 light absorber layer, as it can lead to significant diffusion of the window layer material into Sb2Se3 and damage the device. In this work, we have demonstrated a rapid thermal selenization (RTS) technique that can effectively selenize the Sb2Se3 absorber layer while preventing the S diffusion from the buried CdS window layer into the Sb2Se3 absorber layer. The RTS technique significantly reduces carrier recombination loss and carrier transport resistance and can achieve the highest efficiency of 8.25%. Overall, the RTS method presents a promising approach for enhancing low-dimensional chalcogenide thin films for emerging superstrate chalcogenide solar cell applications. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email