Ln10S14O (Ln = La, Pr, Nd, Sm) Oxysulfides: A Series of Direct n‑Type Semiconductors
Lanthanoid oxysulfides are promising materials for technological applications owing to their magnetic, photoluminescent, catalytic, and optoelectronic properties. Herein, we report the solid-state synthesis and structural characterization of Ln10S14O (Ln = La, Ce, Pr, Nd, Sm) oxysulfides. Then, we p...
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Published in | Chemistry of materials Vol. 34; no. 16; pp. 7553 - 7562 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Chemical Society
23.08.2022
American Chemical Society (ACS) |
Subjects | |
Online Access | Get full text |
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Summary: | Lanthanoid oxysulfides are promising materials for technological applications owing to their magnetic, photoluminescent, catalytic, and optoelectronic properties. Herein, we report the solid-state synthesis and structural characterization of Ln10S14O (Ln = La, Ce, Pr, Nd, Sm) oxysulfides. Then, we present a thorough discussion on their electronic and photophysical properties. Through Tauc plot analysis and the derivation of the absorption spectrum fitting method (DASF), we determine that all oxysulfides have direct band gaps with energies of 2.84 eV (La), 2.02 eV (Ce), 2.56 eV (Pr), 2.64 eV (Nd), and 2.41 eV (Sm). Furthermore, surface photovoltage spectroscopy (SPS) shows photovoltage (ΔCPD) values of −0.4 to −1.1 V for La-, Pr-, Nd-, and Sm-containing compounds when illuminated near the optical band gap, indicating that these oxysulfides are n-type semiconductors, which is consistent with Mott–Schottky analysis. Photovoltages under sub-band gap illumination energy and photovoltage decay data suggest mid-band gap states possibly arising from the lanthanoid 4f orbitals and/or defects within the crystal structure or at the particle surfaces. These photophysical properties suggest possible applications of the oxysulfides in photoelectrochemical and photovoltaic energy conversion. |
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Bibliography: | SC0015329; AC02-76SF00515; RCSA 26780; DMR-2044403; DMR-1828238 National Science Foundation (NSF) USDOE Office of Science (SC), Basic Energy Sciences (BES) Research Corporation for Science Advancement (RCSA) |
ISSN: | 0897-4756 1520-5002 |
DOI: | 10.1021/acs.chemmater.2c01244 |