Chemistry-An Asian Journal
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2023
·Vol. 19
·期 5
·e202301082
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IF 4.1
Jihao Zhang,Chunze Yuan,Hongbin Dou,Ruixue Zhu,Lin Li,Tsu-Chien Weng
Graphical Diverse emission behaviors are demonstrated by investing the impact of protonated/deprotonated Carbon Dots and their interactions with solvents. Ultrafast spectroscopy reveals that the surface modification significantly affects the carrier relaxation rate and quantum yield, emphasizing a distinct preference for deprotonated surface structure in facilitating carrier radiation recombination The intricate nature of the surface structure of carbon dots (CDs) hinders a comprehensive understanding of their emission behavior. In this study, we employ two types of CDs created through acid-alkali treatments, one with surface protonation and the other with surface deprotonation, with the objective of investigating the impact of these surface modifications on carrier behavior using ultrafast spectroscopy techniques. TEM, XRD, FTIR and Raman spectra demonstrate the CDs’ structure, featuring graphitic core and abundant surface functional groups. XPS confirms the successful surface modifications of CDs via protonation and deprotonation. Ultrafast transient absorption (TA) spectroscopy reveals that deprotonation modification may decelerate the relaxation process, thereby increasing the visible PL quantum yields (PLQY). Conversely, protonation may accelerate the relaxation process due to the induced low-energy absorption band, resulting in self-absorption and reduced PLQY. Furthermore, TA analysis of CDs in mixed solvents with different proportions of ethanol shows the beneficial effect of ethanol in decelerating the relaxation process, leading to an increased PLQY of 33.7 % for deprotonated CDs and 22.1 % for protonated CDs. This study illuminates the intricate relationship between surface deprotonation/protonation modifications and carrier behavior in CDs, offering a potential avenue for the design of high-brightness CDs for diverse applications.
研究领域:
材料科学
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光学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
·
2022
·Vol. 10
·期 47
·18025-18032
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IF 8.067
Shu-Yan Wang,Xiao-Juan Zhen,Zhan-Zu Feng,Ming-Jun Xiao,Shi-Ji Li,Wen Shang,Yi-Fan Huang,Qiang Wang,Hao-Li Zhang
Space exploration urgently demands novel irradiation-tolerant materials to build the arsenal for outer space use, among which nonlinear optical materials and devices are ever-increasing attractive. Tin sulfide (SnS), a novel two dimensional (2D) BP-analog with enhanced stability under ambient conditions, has exhibited excellent optoelectronic properties on the ground, but its potential as a candidate for space optics remains to be explored. Herein, the spatial adaptability of SnS was evaluated in the simulated space radiation environment. When exposed to 60Co γ-rays at a dose equal to over 45 year accumulation in a typical earth orbit, SnS still maintained its strong third-order nonlinear saturable absorption ranging from visible to near-infrared spectra. Ultrafast spectroscopy is used to study the radiation effects and relevant damage mechanisms that are difficult to be revealed via conventional techniques. This work not only sheds light on the irradiation-induced ionization damage and defects in SnS from the unique perspective of ultrafast excited state dynamics but also provides general guidance for rational design and screening space radiation-tolerant nonlinear optical materials.
研究领域:
材料科学
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光学
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空间科学
✓ 已验证
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL PHYSICS
·
2020
·Vol. 33
·期 4
·394-400
·
IF 1.067
Liu Jia,Jiang Shen-long,Zhang Qun
We constructed two types of copper-doped metal-organic framework (MOF), i.e ., Cu@UiO- 66-NH 2 and Cu-UiO-66-NH 2 . In the
former, Cu 2+ ions are impregnated in the pore space of the
amine-functionalized, Zr-based UiO-66-NH 2 ; while in the latter, Cu 2+ ions are in-corporated to form a bimetal-center MOF, with Zr 4+ being partially
replaced by Cu 2+ in the Zr−O oxo-clusters. Ultrafast spectroscopy revealed that
the photoinduced relaxation kinetics associated with the ligand-to-cluster charge-transfer
state is promoted for both Cu-doped MOFs relative to undoped one, but in a sequence of
Cu-UiO-66-NH 2 >Cu@UiO-66-NH 2 >UiO-66-NH 2 . Such a
sequence turned to be in line with the trend observed in the visible-light photocatalytic
hydrogen evolution activity tests on the three MOFs. These findings highlighted the subtle
effect of copper-doping location in this Zr-based MOF system, further suggesting that
rational engineering of the specific metal-doping location in alike MOF systems to promote
the photoinduced charge separation and hence suppress the detrimental charge recombination
therein is beneficial for achieving improved performances in MOF-based photocatalysis.
研究领域:
材料科学
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光化学
✓ 已验证
DOI
高影响因子
ADVANCED MATERIALS
·
2025
·Vol. 37
·期 26
·2503496
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IF 26.8
Kaiqi Zhang,Yuling Huang,Shuang Liu,Qihong Xiong,Sikang Zheng,Bin Zhang,Guiwen Wang,Yu Pan,Guang Han,Guoyu Wang,Xu Lu,Xihan Chen,Xiaoyuan Zhou
Thermoelectric materials, like other electronic materials, require high carrier mobility, which is governed by carrier scattering potential. In addition to intrinsic acoustic phonon scattering, the extrinsic factors such as microstructure and atomic arrangement also have great influence on carrier transport in solids, e.g., the emerging thermoelectric material AgSbSe 2 with strong cation disorder. However, the experimental evaluation of total carrier scattering potential and distinguishing the contributions from intrinsic and extrinsic scatterings is challenging at present. Here, the time-resolved ultrafast spectroscopy analysis utilizing a pump-probe scheme is performed to characterize the charge carrier dynamics of AgSbSe 2 with femtosecond time resolution quantitatively. A significantly lowered total carrier scattering potential energy in Cd-doped AgSbSe 2 crystal is determined, resulting from the elimination of grain boundaries and the presence of short-range order that leads to a negative extrinsic scattering potential. The reduction in carrier scattering potential leads to a threefold increase in the average power factor from 323 to 723 K. A maximum thermoelectric figure of merit of 1.7 is achieved in high-quality AgSb 0.973 Cd 0.017 Se 2 crystal at 723 K, with the output efficiency of the single-leg thermoelectric device reaching a competitive value of 8%. This work reveals how to effectively characterize and modulate carrier scattering potential in thermoelectric compounds.
研究领域:
材料科学
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热电学
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凝聚态物理
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超快光谱学
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固体物理
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2024
·
IF 10.7
Ruiding Fei,Jianfeng Zhao,Huinan Wang,Huijuan Lin,Kui Xu,Guang Zeng,Wenchao Wang,Zhiping Yan
The hydrogen evolution capacity of MoS2 is impeded by its intrinsically highly electronegative sulfur sites, which firmly bind absorbed atomic H through S–Hads bonds and subsequently diminish H2 release. Designing effective surface-active sites to optimize atomic hydrogen activation and desorption for the hydrogen evolution reaction (HER) in water, while also expanding near-infrared (NIR) light responsiveness, remains a significant challenge. We have developed complexes of sulfur vacancy (Sv) enriched CdSv capped with W-modified MoS2+x (MoWS2+x) through an in situ substitution approach, followed by a photoreduction reaction. The bimetallic MoWS2+x cocatalyst not only increases the density of unsaturated coordinating S active sites but also attenuates the strength of the S–Hads bond. The optimized MoWS2+x/CdSv hybrid shows synergistic improvement of atomic H activation and desorption for the solar-driven HER, achieving the highest recorded H2-evolution rate of 9166.13 μmol g−1 h−1 under visible light (λ ≥ 420 nm), which marks a substantial improvement (greater than 750%), and an apparent quantum yield of 19.13%. Remarkably, the target photocatalyst, which is abundant in sulfur vacancies within its CdSv component, also achieves H2 production driven by NIR light beyond 780 nm, with a H2 evolution rate of 1326.82 μmol g−1 h−1. Comprehensive experimental and theoretical investigations corroborate that the existence of unsaturated coordinated S sites mitigates the strength of S–Hads bonds, resulting in the high driving force of H2 bubble release from water and long-lived active charge carriers. In this paper, we constructed visible light and NIR-active photocatalysts successfully for hydrogen production, highlighting the synergetic effects within this unique system. Additionally, the photo-behaviors of charge carriers have been investigated by ultra-fast spectroscopic techniques to gain a deeper understanding of the interfacial charge transfer kinetics. This study provides valuable insights into the development and optimization of photocatalysts that are responsive to both NIR and visible light, paving the way for more efficient solar-driven applications.
研究领域:
材料科学
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催化
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光化学
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可再生能源
✓ 已验证
产品关联
DOI
高影响因子
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