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Author |
Zhou, S.; Xu, W.; Xiao, Y.; Xiao, H.; Zhang, J.; Wang, Z.; He, G.; Liu, J.; Li, Y.; Peeters, F.M. |
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Title |
Influence of neutron irradiation on X-ray diffraction, Raman spectrum and photoluminescence from pyrolytic and hot-pressed hexagonal boron nitride |
Type |
A1 Journal article |
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Year |
2023 |
Publication |
Journal of luminescence |
Abbreviated Journal |
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Volume |
263 |
Issue |
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Pages |
120118-8 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
Hexagonal boron nitride (hBN) is considered as an ideal semiconductor material for solid-state neutron detector, owing to its large neutron scattering section because of the low atomic number of B and excellent physical properties. Here we study the influence of neutron irradiation on crystal structure and on intermediate energy state (IMES) levels induced by the presence of impurities and defects in hBN. Large-size and thick pyrolytic and hot-pressed hBN (PBN and HBN) samples, which can be directly applied for neutron detector devices, are prepared and bombarded by neutrons with different irradiation fluences. The SEM and TEM are used to observe the sample difference of PBN and HBN. X-ray diffraction and Raman spectroscopy are applied to examine the influence of neutron irradiation on lattice structures along different crystal directions of PBN and HBN samples. Photoluminescence (PL) is employed to study the effect of neutron irradiation on IMESs in these samples. We find that the neutron irradiation does not alter the in-plane lattice structures of both PBN and HBN samples, but it can release the inter-layer tensions induced by sample growth of the PBN samples. Interestingly and surprisingly, the neutron irradiation does not affect the IMES levels responsible for PL generation, where PL is attributed mainly from phonon-assisted radiative electron-hole coupling for both PBN and HBN samples. Furthermore, the results indicate that the neutron irradiation can weaken the effective carrier-phonon coupling and exciton transitions in PBN and HBN samples. Overall, both PBN and HBN samples show some degree of the resistance to neutron irradiation in terms of these basic physical properties. The interesting and important findings from this work can help us to gain an in-depth understanding of the influence of neutron irradiation on basic physical properties of hBN materials. These effects can be taken into account when designing and applying the hBN materials for neutron detectors. |
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Wos |
001077086300001 |
Publication Date |
2023-08-09 |
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ISSN |
0022-2313 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.6 |
Times cited |
1 |
Open Access |
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Most recent IF: 3.6; 2023 IF: 2.686 |
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Call Number |
UA @ admin @ c:irua:200393 |
Serial |
9047 |
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Author |
Yuan, M.-M.; Wang, L.-D.; Zhang, J.; Ran, M.-J.; Wang, K.; Hu, Z.-Y.; Van Tendeloo, G.; Li, Y.; Su, B.-L. |
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Title |
Cut-off voltage influencing the voltage decay of single crystal lithium-rich manganese-based cathode materials in lithium-ion batteries |
Type |
A1 Journal article |
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Year |
2024 |
Publication |
Journal of colloid and interface science |
Abbreviated Journal |
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Volume |
674 |
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Pages |
238-248 |
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Keywords |
A1 Journal article; Electron microscopy for materials research (EMAT) |
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Abstract |
The voltage decay of Li -rich layered oxide cathode materials results in the deterioration of cycling performance and continuous energy loss, which seriously hinders their application in the high-energy – density lithium -ion battery (LIB) market. However, the origin of the voltage decay mechanism remains controversial due to the complex influences of transition metal (TM) migration, oxygen release, indistinguishable surface/bulk reactions and the easy intra/inter-crystalline cracking during cycling. We investigated the direct cause of voltage decay in micrometer -scale single -crystal Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 (SC-LNCM) cathode materials by regulating the cut-off voltage. The redox of TM and O 2- ions can be precisely controlled by setting different voltage windows, while the cracking can be restrained, and surface/bulk structural evaluation can be monitored because of the large single crystal size. The results show that the voltage decay of SC-LNCM is related to the combined effect of cation rearrangement and oxygen release. Maintaining the discharge cutoff voltage at 3 V or the charging cutoff voltage at 4.5 V effectively mitigates the voltage decay, which provides a solution for suppressing the voltage decay of Lirich and Mn-based layered oxide cathode materials. Our work provides significant insights into the origin of the voltage decay mechanism and an easily achievable strategy to restrain the voltage decay for Li -rich and Mn-based cathode materials. |
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https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=brocade2&SrcAuth=WosAPI&KeyUT=WOS:001261 |
Publication Date |
2024-06-24 |
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ISSN |
0021-9797; 1095-7103 |
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Additional Links |
UA library record; WoS full record; WoS full record |
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Impact Factor |
9.9 |
Times cited |
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Open Access |
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Most recent IF: 9.9; 2024 IF: 4.233 |
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Call Number |
UA @ admin @ c:irua:207026 |
Serial |
9281 |
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Author |
Li, Y.; Xiao, Y.M.; Xu, W.; Ding, L.; Milošević, M.V.; Peeters, F.M. |
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Title |
Magneto-optical conductivity of monolayer transition metal dichalcogenides in the presence of proximity-induced exchange interaction and external electrical field |
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A1 Journal article |
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Year |
2024 |
Publication |
Physical review B |
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109 |
Issue |
16 |
Pages |
165441-14 |
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Keywords |
A1 Journal article; Condensed Matter Theory (CMT) |
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Abstract |
We theoretically investigate the magneto-optical (MO) properties of monolayer (ML) transition metal dichalcogenides (TMDs) in the presence of external electrical and quantizing magnetic fields and of the proximity-induced exchange interaction. The corresponding Landau Level (LL) structure is studied by solving the Schr & ouml;dinger equation and the spin polarization in ML-TMDs under the action of the magnetic field is evaluated. The impact of trigonal warping on LLs and MO absorption is examined. Furthermore, the longitudinal MO conductivity is calculated through the dynamical dielectric function under the standard random-phase approximation (RPA) with the Kubo formula. We take ML-MoS 2 as an example to examine the effects of proximity-induced exchange interaction, external electrical and magnetic fields on the MO conductivity induced via intra- and interband electronic transitions among the LLs. For intraband electronic transitions within the conduction or valence bands, we can observe two absorption peaks in terahertz (THz) frequency range. While the interband electronic transitions between conduction and valence LLs show a series of absorption peaks in the visible range. We find that the proximity-induced exchange interaction, the carrier density, the strengths of the external electrical and magnetic fields can effectively modulate the positions of the absorption peaks and the shapes of the MO absorption spectra. The results obtained from this study can benefit to an in-depth understanding of the MO properties of ML-TMDs which can be potentially applied for magneto-optic, spintronic, and valleytronic devices working in visible to THz frequency bandwidths. |
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001231884200004 |
Publication Date |
2024-04-26 |
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ISSN |
2469-9969; 2469-9950 |
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Additional Links |
UA library record; WoS full record; WoS citing articles |
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Impact Factor |
3.7 |
Times cited |
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Open Access |
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Most recent IF: 3.7; 2024 IF: 3.836 |
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Call Number |
UA @ admin @ c:irua:206589 |
Serial |
9305 |
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