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Abstract Synthesizing solids in molten fluxes enables the rapid diffusion of soluble species at temperatures lower than in solid‐state reactions, leading to crystal formation of kinetically stable compounds. In this study, we demonstrate the effectiveness of mixed hydroxide and halide fluxes in synthesizing complex Sr/Ag/Se in mixed LiOH/LiCl. We have accessed a series of two‐dimensional Sr(Ag1−xLix)2Se2layered phases. With increased LiOH/LiCl ratio or reaction temperature, Li partially substituted Ag to form solid solutions of Sr(Ag1−xLix)2Se2withxup to 0.45. In addition, a new type of intergrowth compound [Sr3Se2][(Ag1−xLix)2Se2] was synthesized upon further reaction of Sr(Ag1−xLix)2Se2with SrSe. Both Sr(Ag1−xLix)2Se2and [Sr3Se2][(Ag1−xLix)2Se2] exhibit a direct band gap, which increases with increasing Li substitution (x). Therefore, the band gap of Sr(Ag1−xLix)2Se2can be precisely tuned via fine‐tuningxthat is controlled by only the flux ratio and temperature.
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Copper’s Role in the Photoluminescence of Ag 1–x Cu x InS 2 Nanocrystals, from Copper-Doped AgInS 2 ( x ∼ 0) to CuInS 2 ( x = 1)
- Award ID(s):
- 1807394
- PAR ID:
- 10105760
- Date Published:
- Journal Name:
- Nano Letters
- Volume:
- 19
- Issue:
- 2
- ISSN:
- 1530-6984
- Page Range / eLocation ID:
- 1318 to 1325
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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null (Ed.)(Bi 1/2 Na 1/2 )TiO 3 (BNT) based ceramics have been the hot topic for a few years because of their multiple functions, from the piezoelectric properties to more recently the electrostatic energy storage performance. However, some basic issues are still unclear, preventing their wide application in real devices. One of them is the underlying conduction mechanism, the interplay of electronic and ionic carriers as a mixed ionic case and the subsequent quantification. This paper deals with the most basic compositions, which are the typical ones from the (1 − x )(Bi 1/2 Na 1/2 )TiO 3 – x BaTiO 3 (BNT– x BT) phase diagram. The conductivity is primarily investigated by impedance spectroscopy, while different equivalent circuits are applied to different conduction mechanisms. A transition from predominantly ionic to predominantly electronic conduction is revealed to occur with the increase in BaTiO 3 concentration. The mixed ionic–electronic conduction in the composition near the morphotropic phase boundary, namely BNT–7%BT, is identified and then quantified. To verify our interpretation of impedance results, dc degradation is, for the first time, conducted in this family of materials, from which the electronic and ionic conductions can be easily separated by accessing the mean time to failure. The successful combination of the two methods enables us to have an overview of how the oxygen vacancy dynamics in the BNT– x BT system depends upon the phase nature or the domain structure.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1021/acs.nanolett.8b04905
