Ultrafast fiber lasers have significant applications in ultra-precision manufacturing, medical diagnostics, medical treatment, precision measurement and astronomical detection, owing to their ...ultra-short pulse width and ultra-high peak-power. Since graphene was first explored as an optical saturable absorber for passively mode-locked lasers in 2009, many other 2D materials beyond graphene, including phosphorene, antimonene, bismuthene, transition metal dichalcogenides (TMDs), topological insulators (TIs), metal-organic frameworks (MOFs) and MXenes, have been successively explored, resulting in rapid development of novel 2D materials-based saturable absorbers. Herein, we review the latest progress of the emerging 2D materials beyond graphene for passively mode-locked fiber laser application. These 2D materials are classified into mono-elemental, dual-elemental and multi-elemental 2D materials. The atomic structure, band structure, nonlinear optical properties, and preparation methods of 2D materials are summarized. Diverse integration strategies for applying 2D materials into fiber laser systems are introduced, and the mode-locking performance of the 2D materials-based fiber lasers working at 1-3 μm are discussed. Finally, the perspectives and challenges facing 2D materials-based mode-locked fiber lasers are highlighted.
The latest progress of emerging 2D materials applied in ultrafast fiber lasers is summarized, and perspectives and challenges are discussed.
Using first-principles calculations, we investigate the adsorption of various gas molecules (H
2
, O
2
, H
2
O, NH
3
, NO, NO
2
, and CO) on monolayer MoS
2
. The most stable adsorption ...configuration, adsorption energy, and charge transfer are obtained. It is shown that all the molecules are weakly adsorbed on the monolayer MoS
2
surface and act as charge acceptors for the monolayer, except NH
3
which is found to be a charge donor. Furthermore, we show that charge transfer between the adsorbed molecule and MoS
2
can be significantly modulated by a perpendicular electric field. Our theoretical results are consistent with the recent experiments and suggest MoS
2
as a potential material for gas sensing application.
Magnetic two-dimensional materials have attracted considerable attention for their significant potential application in spintronics. In this study, we present a high-quality Fe-doped SnS2 monolayer ...exfoliated using a micromechanical cleavage method. Fe atoms were doped at the Sn atom sites, and the Fe contents are ∼2.1%, 1.5%, and 1.1%. The field-effect transistors based on the Fe0.021Sn0.979S2 monolayer show n-type behavior and exhibit high optoelectronic performance. Magnetic measurements show that pure SnS2 is diamagnetic, whereas Fe0.021Sn0.979S2 exhibits ferromagnetic behavior with a perpendicular anisotropy at 2 K and a Curie temperature of ~31 K. Density functional theory calculations show that long-range ferromagnetic ordering in the Fe-doped SnS2 monolayer is energetically stable, and the estimated Curie temperature agrees well with the results of our experiment. The results suggest that Fe-doped SnS2 has significant potential in future nanoelectronic, magnetic, and optoelectronic applications.
Polarized detection has been brought into operation for optics applications in the visible band. Meanwhile, an advanced requirement in short-wave near-infrared (SW-NIR) (700–1100 nm) is proposed. ...Typical IV–VI chalcogenides2D GeSe with anisotropic layered orthorhombic structure and narrow 1.1–1.2 eV band gappotentially meets the demand. Here we report the unusual angle dependences of Raman spectra on high-quality GeSe crystals. The polarization-resolved absorption spectra (400–950 nm) and polarization-sensitive photodetectors (532, 638, and 808 nm) both exhibited well-reproducible cycles, distinct anisotropic features, and typical absorption ratios α y /α x ≈ 1.09 at 532 nm, 1.26 at 638 nm, and 3.02 at 808 nm (the dichroic ratio I py/I px ≈ 1.09 at 532 nm, 1.44 at 638 nm, 2.16 at 808 nm). Obviously, the polarized measurement for GeSe showed superior anisotropic response at around 808 nm within the SW-NIR band. Besides, the two testing methods have demonstrated the superior reliability for each other. For the layer dependence of linear dichroism, the GeSe samples with different thicknesses measured under both 638 and 808 nm lasers identify that the best results can be achieved at a moderate thickness about 8–16 nm. Overall, few-layer GeSe has capacity with the integrated SW-NIR optical applications for polarization detection.
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IJS, KILJ, NUK, PNG, UL, UM
The structural and electronic properties of MoS2/MoSe2 bilayers are calculated using first-principles methods. It is found that the interlayer van der Waals interaction is not strong enough to form a ...lattice-matched coherent heterostructure. Instead, a nanometer-scale Moiré pattern structure will be formed. By analyzing the electronic structures of different stacking configurations, we predict that the valence-band maximum (VBM) state will come from the Γ point due to interlayer electronic coupling. This is confirmed by a direct calculation of a Moiré pattern supercell containing 6630 atoms using the linear scaling three-dimensional fragment method. The VBM state is found to be strongly localized, while the conduction band minimum (CBM) state is only weakly localized, and it comes from the MoS2 layer at the K point. We predict such wave function localization can be a general feature for many two-dimensional (2D) van der Waals heterostructures and can have major impacts on the carrier mobility and other electronic and optical properties.
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IJS, KILJ, NUK, PNG, UL, UM
Ferroptosis, a form of regulated cell death, is characterized by an excessive degree of iron accumulation and lipid peroxidation. Although it was originally identified only in cells expressing a ...mutant RAS oncogene, ferroptosis has also been found in normal cells following treatment by small molecules (e.g., erastin and RSL3) or drugs (e.g., sulfasalazine, sorafenib, and artesunate), which target antioxidant enzyme systems, especially the amino acid antiporter system x
and the glutathione peroxidase GPX4. Dysfunctional ferroptosis is implicated in various physiological and pathological processes (e.g., metabolism, differentiation, and immunity). Targeting the ferroptotic network appears to a new treatment option for diseases or pathological conditions (e.g., cancer, neurodegeneration, and ischemia reperfusion injury). While the molecular machinery of ferroptosis remains largely unknown, several transcription factors (e.g., TP53, NFE2L2/NRF2, ATF3, ATF4, YAP1, TAZ, TFAP2C, SP1, HIF1A, EPAS1/HIF2A, BACH1, TFEB, JUN, HIC1, and HNF4A) play multiple roles in shaping ferroptosis sensitivity through either transcription-dependent or transcription-independent mechanisms. In this review, we summarize recent progress in understanding the transcriptional regulation underlying ferroptotic cell death, and discuss how it has provided new insights into cancer therapy.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
2D layered materials such as graphene, black phosphorus (BP), transition metal dichalcogenides (TMDCs), and their hybrid systems exhibit wide coverage of bandgaps, unique crystal structures, and the ...facile integration for potential applications in photonic and optoelectronic devices. In the recent two years, various 2D functional systems have been developed with novel optoelectronic properties, thereby expanding the functional applications. Beyond the speed, efficiency, or sensitivity, these 2D crystals can offer additional advantages and distinct applications in terms of spectrum range, polarization, intensity, and structural designs. The main contents here focus on optoelectronic and photonic devices with unique functional applications, especially mentioning areas as follows: long‐wavelength photodetector, 2D polarization‐sensitive photodetector, 2D optoelectronic memory, and 2D material‐based optical modulator. For each section, the device design, performance, and operational principles are investigated and systematically discussed. Finally, the current research status is summarized and perspectives on possible applications in future are offered.
Novel 2D materials and related hybrid systems are widely investigated and used for the realization of multifunctional devices. This review is focused on 2D material‐based optoelectronic and photonic devices with unique functional applications, especially long‐wavelength photodetector, polarization‐sensitive photodetector, optoelectronic memory, and saturable absorber. The device design, performance and operational principles are introduced.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Van der Waals heterostructures designed by assembling isolated two‐dimensional (2D) crystals have emerged as a new class of artificial materials with interesting and unusual physical properties. ...Here, the multilayer MoS2–WS2 heterostructures with different configurations are reported and their optoelectronic properties are studied. It is shown that the new heterostructured material possesses new functionalities and superior electrical and optoelectronic properties that far exceed the one for their constituents, MoS2 or WS2. The vertical transistor exhibits a novel rectifying and bipolar behavior, and can also act as photovoltaic cell and self‐driven photodetector with photo‐switching ratio exceeding 103. The planar device also exhibits high field‐effect ON/OFF ratio (>105), high electron mobility of 65 cm2/Vs, and high photoresponsivity of 1.42 A/W compared to that in isolated multilayer MoS2 or WS2 nanoflake transistors. The results suggest that formation of MoS2–WS2 heterostructures could significantly enhance the performance of optoelectronic devices, thus open up possibilities for future nanoelectronic, photovoltaic, and optoelectronic applications.
Newly designed MoS
2
–WS
2
heterostructures perform novel and enhanced optoelectronic performances. Vertical transistors possess new functionalities such as rectifying, bipolarity, photovoltaic effect, and self‐driven photodetection. Planar devices exhibit superior optoelectronic properties with high field‐effect ON/OFF ratio (>105), electron mobility of 65 cm2/Vs, and photoresponsivity of 1.42 A/W that far exceed the one for their constituents MoS2 or WS2.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The structural, electronic, transport and optical properties of black phosphorus/MoS2 (BP/MoS2) van der Waals (vdw) heterostructure are investigated by using first principles calculations. The band ...gap of BP/MoS2 bilayer decreases with the applied normal compressive strain and a semiconductor-to-metal transition is observed when the applied strain is more than 0.85 Å. BP/MoS2 bilayer also exhibits modulation of its carrier effective mass and carrier concentration by the applied compressive strain, suggesting that mobility engineering and good piezoelectric effect can be realized in BP/MoS2 heterostructure. Because the type-II band alignment can facilitate the separation of photo-excited electrons and holes, and it can benefit from the great absorption coefficient in ultra-violet region, the BP/MoS2 shows great potential to be a very efficient ultra-violet photodetector.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Substrate inhibition of enzymes can be a major obstacle to the production of valuable chemicals in engineered microorganisms. Here, we show substrate inhibition of lycopene cyclase as the main ...limitation in carotenoid biosynthesis in Yarrowia lipolytica. To overcome this bottleneck, we exploit two independent approaches. Structure-guided protein engineering yields a variant, Y27R, characterized by complete loss of substrate inhibition without reduction of enzymatic activity. Alternatively, establishing a geranylgeranyl pyrophosphate synthase-mediated flux flow restrictor also prevents the onset of substrate inhibition by diverting metabolic flux away from the inhibitory metabolite while maintaining sufficient flux towards product formation. Both approaches result in high levels of near-exclusive β-carotene production. Ultimately, we construct strains capable of producing 39.5 g/L β-carotene at a productivity of 0.165 g/L/h in bioreactor fermentations (a 1441-fold improvement over the initial strain). Our findings provide effective approaches for removing substrate inhibition in engineering pathways for efficient synthesis of natural products.
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