Electrochromic properties can be enhanced by constructing photonic architectures, in which the reflectance contributes to optical modulation along with the intrinsic dynamic absorptivity of the material. However, optimization of reflectance is challenging without a rational design approach. Here, electrochemically tunable Bragg reflectors are demonstrated that are tuned to be highly transparent in the “off” state, achieving synergistic dynamic optical modulation of absorption and reflection in the visible and near‐infrared range. These Bragg stacks are composed of alternating doped semiconductor nanocrystal (NC) layers of 5 nm sized oxygen vacancy‐doped WO3−
- NSF-PAR ID:
- 10426997
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- RSC Advances
- Volume:
- 13
- Issue:
- 2
- ISSN:
- 2046-2069
- Page Range / eLocation ID:
- 1236 to 1244
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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null (Ed.)Development of new host materials containing heavy elements for radiation detection is highly desirable. In this work, dibarium octafluorohafnate, Ba 2 HfF 8 , doped with rare-earth ions, was synthesized as cube-shaped nanocrystals via a facile hydrothermal method. The host lattice contains two Ba 2+ crystallographic sites, and dopants on these sites exhibit site-dependent photoluminescence (PL), cathodoluminescence (CL) and X-ray excited radioluminescence (RL) characteristics. Single doping contents were optimized as 25 mol% Tb 3+ and 5 mol% Eu 3+ . In Ba 2 HfF 8 :Tb 3+ –Eu 3+ codoped nanocrystals, preferrable occupation of Eu 3+ and Tb 3+ at two different Ba 2+ sites in the host lattice was observed. The nanocubes exhibited enhanced emissions over micron sized particles. In PL, the presence of Tb 3+ ions significantly enhanced the emission intensity of Eu 3+ ions due to energy transfer from the Tb 3+ to Eu 3+ ions, while under high-energy irradiation in CL or RL, Tb 3+ emission was intensified. X-ray induced RL with afterglow in seconds was observed. It was found that the codoped sample showed higher sensitivity than the singly doped sample, indicating that codoping is an effective strategy to develop a scintillator with this host structure for high-energy radiation detection.more » « less
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Y. Lei, D. Butler, M. C. Lucking, F. Zhang, T. Xia, K. Fujisawa, T. Granzier-Nakajima, R. Cruz-Silva, M. Endo, H. Terrones, M. Terrones, A. Ebrahimi,
Sci. Adv. 6 , 4250–4257 (2020).V. Kammarchedu, D. Butler, A. Ebrahimi,
Anal. Chim. Acta .1232 , 340447 (2022).H. Yoon, J. Nah, H. Kim, S. Ko, M. Sharifuzzaman, S. C. Barman, X. Xuan, J. Kim, J. Y. Park,
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r ‐plane sapphire is used. Electronic measurements demonstrate that 1 at% Re doping achieves nearly degenerate n‐type doping, which agrees with density functional theory calculations. Moreover, low‐temperature photoluminescence indicates a significant quench of the defect‐bound emission when Re is introduced, which is attributed to the MoO bond and sulfur vacancies passivation and reduction in gap states due to the presence of Re. The work presented here demonstrates that Re doping of MoS2is a promising route toward electronic and photonic engineering of 2D materials. -
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Abstract Tungsten‐doped titanium‐dioxide (W‐TiO2) nanoparticles are successfully synthesized using a multiple‐diffusion‐flame burner with a separate center tube. Vaporized titanium tetra‐isopropoxide (TTIP) precursor issues from a center tube to produce TiO2nanoparticles, while a tungsten mesh, suspended above the surrounding multiple over‐ventilated hydrogen diffusion flames, serves as the solid‐phase metal doping source. At a lower tungsten loading rate, W‐TiO2nanoparticles are generated, as indicated by an obvious angle shift of 0.15° for the entire x‐ray diffraction spectrum. However, at a higher tungsten loading rate, homogenous nucleation of WO
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