RESUMEN
Hepatocellular carcinoma (HCC) is one of the most lethal malignancies worldwide. However, the immune tolerance limits the effect of chemotherapeutic drugs. Therefore, the mechanism of cisplatin in promoting PD-L1 expression by YAP1 was investigated in the present study, and we found that cisplatin increased the expression level of YAP1 in the mouse liver with H22 cells. Meanwhile, cisplatin improved the expression level of PD-L1, IL-1ß and CCL2 in the tumor microenvironment. Further, cisplatin also enhanced the expression level of YAP1 in shYAP1 HepG2215 cells. The expression of PD-L1 was decreased by Verteporfin, YAP1 inhibitor, during the treatment of DEN/TCPOBOP-induced liver cancer in C57BL/6 mice. These results suggested that cisplatin could deteriorate the immunosuppressive microenvironment through increasing PD-L1, CCL2, IL-1ß by upregulated YAP1 expression. Therefore, the study suggested that YAP1 blockade destroyed the immunosuppressive microenvironment of cancer to improve the effect of chemotherapy in HCC.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/metabolismo , Antígeno B7-H1/biosíntesis , Carcinoma Hepatocelular/metabolismo , Cisplatino/farmacología , Neoplasias Hepáticas/metabolismo , Factores de Transcripción/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Antineoplásicos/farmacología , Antígeno B7-H1/genética , Antígeno B7-H1/metabolismo , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/patología , Línea Celular Tumoral , Células Hep G2 , Humanos , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/patología , Neoplasias Hepáticas Experimentales/tratamiento farmacológico , Neoplasias Hepáticas Experimentales/metabolismo , Neoplasias Hepáticas Experimentales/patología , Masculino , Ratones , Ratones Endogámicos BALB C , Fármacos Fotosensibilizantes/farmacología , Transducción de Señal , Factores de Transcripción/genética , Microambiente Tumoral , Verteporfina/farmacología , Proteínas Señalizadoras YAPRESUMEN
Bismuth has garnered tremendous interest for Na-ion batteries (NIBs) due to potentially high volumetric capacity. Yet, the bismuth upon sodiation/desodiation experiencing structure and phase transitions remains unclear, which sets a challenge for accessing nanotechnology and nanofabrication to achieve its applicability. Here, we use in situ transmission electron microscopy to disclose the structure and phase transitions of layered bismuth (few-layer bismuth nanosheets) during Na+ intercalation and alloying processes. Multistep phase transitions from Bi â NaBi â c-Na3Bi (cubic) â h-Na3Bi (hexagonal) are clearly identified, during which the Na+ migration from interlayer to in-plane evokes the structure transition from ABCABC stacking type of c-Na3Bi to ABABAB stacking type of h-Na3Bi. It is found that the metastable c-Na3Bi devotes to buffer the dramatic structure changes from thermodynamic stable h-Na3Bi, which unveils the origin of volume expansion for bismuth and has important consequences for 2D in-plane structure. As the lateral ductility can efficiently alleviate the in-plane mechanical strain caused by the Na+ migration, the few-layer bismuth nanosheet exhibits a potential cyclability for NIBs. Our findings will encourage more attention to bismuthene as a novel anode material for secondary batteries.
RESUMEN
Coordination-related, 2D structural phase transitions are a fascinating facet of 2D materials with structural degeneracy. Phosphorene and its new phases, exhibiting unique electronic properties, have received considerable attention. The 2D group IV-IV monochalcogenides (i.e. GeS, GeSe, SnS and SnSe) like black phosphorous possess puckered layered orthorhombic structure. The 2D group IV-IV monochalcogenides with advantages of earth-abundance, less toxicity, environmental compatibility and chemical stability, can be widely used in optoelectronics, piezoelectrics, photodetectors, sensors, Li-batteries and thermoelectrics. In this review, we summarized recent research progress in theory and experiment, which studies the fundamental properties, applications and fabrication of 2D group IV-IV monochalcogenides and their new phases, and brings new perspectives and challenges for the future of this emerging field.
RESUMEN
Highly stable antimonene, as the cousin of phosphorene from group-VA, has opened up exciting realms in the two-dimensional (2D) materials family. However, pristine antimonene is an indirect band gap semiconductor, which greatly restricts its applications for optoelectronics devices. Identifying suitable materials, both responsive to incident photons and efficient for carrier transfer, is urgently needed for ultrathin devices. Herein, by means of first-principles computations we found that it is rather feasible to realize a new class of 2D materials with a direct bandgap and high carrier mobility, namely antimonene oxides with different content of oxygen. Moreover, these tunable direct bandgaps cover a wide range from 0 to 2.28 eV, which are crucial for solar cell and photodetector applications. Especially, the antimonene oxide (18Sb-18O) is a 2D topological insulator with a sizable global bandgap of 177 meV, which has a nontrivial Z2 topological invariant in the bulk and the topological states on the edge. Our findings not only introduce new vitality into 2D group-VA materials family and enrich available candidate materials in this field but also highlight the potential of these 2D semiconductors as appealing ultrathin materials for future flexible electronics and optoelectronics devices.
RESUMEN
Experimentally, GeS nanosheets have been successfully synthesized using vapor deposition processes and the one-pot strategy. Quite recently, GeS monolayer, the isoelectronic counterpart of phosphorene, has attracted much attention due to promising properties. By means of comprehensive first-principles calculations, we studied the stability and electronic properties of GeS monolayer. Especially, electric field and in-plane strain were used to tailor its electronic band gap. Upon applying electric field, the band gap of GeS monolayer greatly reduces and a semiconductor-metal transition happens under the application of a certain external electric field. Our calculations reveal that the band gaps of GeS monolayer are rather sensitive to the external electric field. On the other hand, for GeS under external strain, quite interestingly, we found that the band gap presents an approximately linear increase not only under compression strain but also under tensile strain from -10% to 10%. For biaxial compressive and tensile strains, the band gap follows the same trend as that of the uniaxial in the zigzag x direction. The present results provide a simple and effective route to tune the electronic properties of GeS monolayer over a wide range and also facilitate the design of GeS-based two-dimensional devices.
RESUMEN
Notched beam specimens were loaded by the three-point bending test device, and the effects of different volume contents and combinations of steel fibers on the tensile properties of hybrid steel fiber-reinforced self-compacting concrete (HSFRSCC) were studied. The failure law and strain field distribution of the specimens were studied by digital image correlation (DIC) technology. Moreover, the curves between the load and crack mouth opening displacement (CMOD) of 18 groups of hybrid steel fiber-reinforced concrete specimens were obtained, and the stress-strain curves of 18 groups of specimens were derived from the load-CMOD curves. The results show that both single and hybrid steel fibers can improve the crack deformation resistance and tensile properties of concrete, but hybrid steel fibers have a more significant improvement effect. Only when the content of steel fiber is more than 0.6% can it have a more obvious postpeak descending section, and hybrid steel fiber has higher postpeak deformation capacity and flexural toughness. The fundamental reason why concrete with hybrid steel fibers has better tensile properties is that micro and macro steel fibers cooperate with each other to resist cracks, improving the toughness of concrete after cracking. Finally, the mechanism of different size and volume content of steel fiber was analyzed from the micro level, which can be used as a reference for the engineering design of HSFRSCC in the future.
RESUMEN
ETHNOPHARMACOLOGICAL RELEVANCE: Metabolic dysfunction-associated fatty liver disease (MAFLD) is the most common chronic liver disease worldwide. However, its complex pathogenesis and lack of effective drugs for treating it present significant challenges. Si-Ni-San (SNS) is one of the representative formulas for treating patients with MAFLD in traditional Chinese medicine (TCM) clinics. According to our previous work, SNS reduces lipid droplet (LD) deposition in livers of mice with MAFLD. AIM OF THE STUDY: To elucidate the mechanism of SNS in reducing LD deposition in MAFLD. MATERIALS AND METHODS: First, LD areas were detected with Oil red O staining in HepG2 cells induced by oleic acid (OA). Cell Counting Kit-8 (CCK-8) assay was used to test cell viability after treatment with different concentrations of SNS serum. The expression of Yes-associated protein 1 (YAP1) was monitored by Western blot. Second, C57BL/6 mice were fed a high-fat diet (HFD) for 12 weeks and gavaged with SNS decoction during the 11th and 12th weeks. Then, the weight of the body and the liver was examined. LD numbers and their locations in the liver were detected by triglyceride (TG) assay and hematoxylin and eosin staining (H&E). The expression levels of YAP1 and perilipin2 (PLIN2) were detected using Western blot and immunohistochemistry (IHC) in liver tissues. Finally, active ingredients of SNS decoction and SNS serum were identified by liquid chromatography-mass spectrometry (LC-MS). Finally, molecular docking was performed between the compounds in SNS and YAP1 to analyze their active interaction. RESULTS: Cellular experiments showed that SNS serum reduced LD vacuoles and YAP1 expression in OA-induced HepG2 cells. Animal experiments confirmed that LD vacuoles, PLIN2 expression (3.16-fold), and YAP1 expression (2.50-fold) were increased in the HFD group compared with the normal diet (ND) group. SNS reduced LD vacuoles, TG content (0.84-fold), PLIN2 expression (0.33-fold), and YAP1 expression (0.27-fold) compared with the normal saline (NS) group in Yap1Flox mice with MAFLD. In SNS, baicalein-6-glucuronide, desoxylimonin, galangin-7-glucoside, glycyrrhizic-acid, licoricesaponin-K2, and nobiletin showed a high binding effect with YAP1. Knockout of hepatocyte YAP1 reduced LD vacuoles, TG content (0.40-fold), and PLIN2 expression (0.62-fold) in mice. Meanwhile, SNS reduced LD vacuoles, TG content (0.70-fold), and PLIN2 expression (0.19-fold) in Yap1LKO mice with MAFLD. The effect of SNS in reducing TG and PLIN2 was diminished in Yap1LKO mice compared with Yap1Flox mice. CONCLUSION: SNS reduced LD deposition and YAP1 expression in MAFLD liver cells both in vivo and in vitro. YAP1 was highly expressed in livers with MAFLD, and knockout of hepatocellular YAP1 reduced LD deposition in mice. SNS reduced LD deposition associated with decreased YAP1 in MAFLD liver cells.
Asunto(s)
Gotas Lipídicas , Enfermedad del Hígado Graso no Alcohólico , Ratones , Animales , Gotas Lipídicas/metabolismo , Simulación del Acoplamiento Molecular , Ratones Endogámicos C57BL , Ratones Noqueados , Enfermedad del Hígado Graso no Alcohólico/metabolismo , Hígado , Triglicéridos/metabolismo , Dieta Alta en Grasa , Proteínas Adaptadoras Transductoras de Señales/metabolismoRESUMEN
The advantages of 2D materials in alleviating the issues of short-channel effect and power dissipation in field-effect transistors (FETs) are well recognized. However, the progress of complementary integrated circuits has been stymied by the absence of high-performance (HP) and low-power (LP) p-channel transistors. Therefore, we conducted an investigation into the electronic and ballistic transport characteristics of monolayer Be2C, which features quasi-planar hexacoordinate carbons, by employing nonequilibrium Green's function combined with density functional theory. Be2C monolayer has planar anticonventional bonds and a direct bandgap of 1.53 eV. The Ion of p-type Be2C HP FETs can achieve a remarkable 2767 µA µm-1. All of the device properties of 2D Be2C FETs can exceed the demands of the International Roadmap for Devices and Systems. The excellent properties of Be2C as a 2D p-orbital material with a high hole mobility are discussed from different aspects. Our findings thus illustrate the tremendous potential of 2D Be2C for the next generation of HP and LP electronics applications.
RESUMEN
Combined use of thermal analysis techniques can realize complementarity of different characterization methods. Comprehensive thermal analysis with both thermogravimetric analysis and differential thermal analysis (TG/DTA) can measure not only mass change of a sample but also its temperature change during programmed heating-induced reaction or phase transition processes, thereby obtaining multiaspect thermal information of the material such as dehydration, structural decomposition, phase change and thermal stability. This study proposes and develops a MEMS chip-based TG/DTA microsystem that integrates both programmed heating and detecting elements into a TG chip and a DTA chip to enable the microinstrument performing TG/DTA joint characterization under microscope observation. The TG chip contains a self-heating resonant microcantilever to measure heating-induced mass change of a sample and the DTA chip is with a microheater and a temperature-detecting thermopile integrated on a suspended thermal-insulating diaphragm. Only nanogram and microgram-level samples are needed for the TG and DTA chips, thereby achieving safe measurement to energetic materials such as strong oxidants. The chip-based microinstrument surpasses the state-of-the-art commercial TG/DTA instruments that have, in the long term, suffered from large sample-amount (milligram level) requirements and have been unable to measure energetic materials. Compared with commercial instruments, the chip-based microinstrument is advantageous given its more accurate analysis, much higher heating rate, much smaller instrument volume and much lower power consumption, etc. The microinstrument has been fabricated by using wafer-level MEMS techniques. Testing results show that the mass-detection sensitivity of the TG-chip is as high as 0.45 Hz/pg in air and the temperature sensitivity of the DTA chip achieves 2.9 mV/K under the high heating rate of 25 °C/s. The strong oxidant of KMnO4 is analyzed with the TG/DTA joint characterization under microscopic observation. At the same time as microscope observation of the thermal decomposition phenomena, two-step thermal decomposition process of KMnO4 is identified and the thermal decomposition temperatures are obtained. The TG/DTA microinstrument is promising to be applied for study of various materials.
RESUMEN
OBJECTIVE: To analyse the saliva microbial abundance and composition by 16s rRNA sequence during Helicobacter pylori (H.pylori) eradication. STUDY DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Hebei University of Chinese Medicine, Hebei Provincial Hospital of Traditional Chinese Medicine, from March 2019 to January 2020. METHODOLOGY: The saliva microbial were analysed before and after the bismuth-containing quadruple therapy. A total of ten saliva samples (three groups) were enrolled in the study. The authors used the linear discriminant analysis effect size (LEfSe) method and Welch's t-test for comparative analysis to identify which taxa could be significantly affected in three groups. RESULTS: H.pylori 16S rRNA gene sequence was not detected in the ten saliva samples. The abundance of Prevotella_sp._oral_clone_P4PB_83_P2 from healthy adults was higher than H.pylori-positive patients. Moreover, after the bismuth-containing quadruple therapy, the diversity and richness of saliva bacteria reduced. Lautropia, Burkholderiales, uncultured bacterium, Burkholderiaceae, and Actinomyces were enriched in H.pylori-positive patient samples after the bismuth-containing quadruple therapy. CONCLUSION: The diversity and richness of salivary microbiome were reduced in H.pylori-positive patient, and bismuth-containing quadruple therapy affected oral microbiota. Key Words: Helicobacter pylori, Saliva, Microbiota, RNA, Bismuth.
Asunto(s)
Infecciones por Helicobacter , Helicobacter pylori , Microbiota , Adulto , Amoxicilina , Antibacterianos/uso terapéutico , Quimioterapia Combinada , Infecciones por Helicobacter/tratamiento farmacológico , Helicobacter pylori/genética , Humanos , Inhibidores de la Bomba de Protones/uso terapéutico , ARN Ribosómico 16S/genéticaRESUMEN
Emerging two-dimensional narrow band gap materials with tunable band gaps and unique electrical and optical properties have shown tremendous potential in broadband photodetection. Nevertheless, large dark currents severely hinder the performance of photodetectors. Here, a MoS2/Ta2NiSe5 van der Waals heterostructure device was successfully fabricated with a high rectification ratio of â¼104 and an ultralow reverse bias current of the pA level. Excitingly, the charge transfer and the generation of the built-in electric field of heterostructures have been proved by theory and experiment, which effectively suppress dark currents. The dark current of the heterostructure reduces by nearly 104 compared with the pure Ta2NiSe5 photodetector at Vds = 1 V. The MoS2/Ta2NiSe5 device exhibits excellent photoelectric performance with the maximum responsivity of 515.6 A W-1 and 0.7 A W-1 at the wavelengths of 532 and 1064 nm under forward bias, respectively. In addition, the specific detectivity is up to 3.1 × 1013 Jones (532 nm) and 2.4 × 109 Jones (1064 nm). Significantly, the device presents an ultra-high gain of 6 × 107 and an exceptional external quantum efficiency of 1.2 × 105% under 532 nm laser irradiation. The results reveal that the MoS2/Ta2NiSe5 heterostructure provides an essential platform for the development and application of high-performance broadband optoelectronic devices.
RESUMEN
Direct bandgap and significant anisotropic properties are crucial and beneficial for nanoelectronic applications. In this work, through first-principles calculations, we investigate novel two-dimensional (2D) α-XC (X = P, As, Sb, Bi) materials, which possess a direct bandgap of 0.73 to 1.40 eV with remarkable anisotropic electronic properties. Intriguingly, 2D α-XC presents the highest electron mobility near 8 × 103 cm2 V-1 s-1 along the Γ-X direction. Moreover, the transfer characteristics of the 2D α-XC TFETs are thoroughly assessed through NEGF methods. AsC TFETs demonstrate an on-state current larger than 2.2 × 103 µA µm-1, which can satisfy the International Technology Roadmap for Semiconductors (ITRS) for high-performance requirements. In particular, the minimum value of subthreshold swing of devices is as low as 15 mV dec-1, indicating excellent device switching characteristics. The relevant calculation results show that 2D α-XC monolayers could be a promising candidate in next-generation high-performance device applications.
RESUMEN
Cervical cancer is the fourth most common cancer among females worldwide. In spite of advances in detection and treatment, it is still one of the most dangerous gynecological malignancies in the world, especially in developing countries, and seriously threatens human health. Circular RNA (circRNA) is a special new type of endogenous noncoding RNA discovered recently. They form a covalently closed continuous loop and are specifically expressed in the eukaryotic transcriptome. With further understanding of circular RNA, a large number of studies have determined the key regulatory role of circRNA in a variety of diseases, especially cancer (including cervical cancer, liver cancer, and lung cancer). In addition, it has also been found that the abnormal expression of circRNA is related to its pathological characteristics in cervical cancer tissue, which can be used as a potential indicator for early screening and diagnosis of cervical cancer, targeted therapy, and prognosis prediction. This article summarizes the recent research achievements of circRNAs in cervical cancer. We briefly described the abnormal expression of circRNA in cervical cancer and discussed the involvement of circRNA in the occurrence process of cervical cancer by regulating cell proliferation, migration, invasion, and apoptosis. We believe that circRNA has potential value as a biomarker in the diagnosis and prognosis of cervical cancer.
RESUMEN
OBJECTIVE: Serum microRNAs (miRNAs) may serve as biomarkers in various cancers. Our study aims to explore the roles of miR-497 and miR-1246 in hepatocellular carcinoma (HCC). METHODS: The expression levels of miR-497 and miR-1246 were measured by RT-PCR. A correlation analysis was conducted between the expression levels of miR-497 and miR-1246 and clinicopathological characteristics of patients. The receiver operating characteristic (ROC) curve was applied to evaluate the diagnostic efficacy in HCC. In addition, bioinformatics tools were also utilized to predict the potential targets of miR-497 and miR-1246. RESULTS: The expression level of miR-497 in HCC was significantly down-regulated compared with the control group while the miR-1246 revealed a significantly higher expression level in HCC. There was a significant correlation demonstrated between the expression levels of miR-497 and miR-1246 in preoperative serum of HCC and the differentiation degree, Tumor Node Metastasis (TNM) classification, and metastasis. The expression levels of serum miR-497 and miR-1246 were significantly associated with the diagnosis, prognosis, and overall survival rate of patients with HCC. Moreover, the potential target genes of miR-497 in HCC include ARL2, UBE2Q1, PHF19, APLN, CHEK1, CASK, SUCO, CCNE1, and KIF23. The low expression of these nine genes is associated with a better prognosis of HCC patients. AUTS2 is a novel target gene of miR-1246, and its low expression is significantly related to the low overall survival rate of HCC patients. CONCLUSIONS: miR-497 and miR-1246 are possibly involved in the progression of HCC by regulating target genes, respectively, and could serve as biomarkers in HCC.
RESUMEN
Objective To investigate the effect of N-acetylcysteine (NAC) on the proliferation of fibroblast-like synoviocytes (FLS) treated with low concentration of hydrogen peroxide (H2O2) in rats with adjuvant arthritis (AA) and its mechanism. Methods Twenty SD rats were divided into a normal group and a model group (10 rats in each group). The model group was established by subcutaneous injection of Freund's complete adjuvant into the toe of rats, and the rats were sacrificed 28 days later. The contents of serum malondialdehyde (MDA) were detected by thiobarbituric acid method; the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were determined by hydroxylamine method and colorimetry respectively; and Nrf2 and Keap1 proteins in ankle synovial tissues of AA rats were detected by immunohistochemistry. AA-FLS were isolated, cultured, and identified by digestion of ankle joint slides of AA rats in vitro. The effects of NAC at different concentrations (final concentration 0, 0.3, 0.9, 3, 10, 30, 90, 180 µmol/L) on the activity of AA-FLS treated with H2O2 at low concentration (5 µmol/L) were detected by CCK-8 assay. The content of mitochondrial reactive oxygen species (ROS) in AA-FLS was detected by MitoSOX fluorescent probe. The effects of NAC (final concentration 0, 3, 10, 30 µmol/L) on Nrf2 and Keap1 protein expressions in AA-FLS treated with H2O2 at low concentration were detected by Western blotting. Results Compared with those in the control group, in AA model, the MDA level increased and SOD and GSH-Px levels decreased in serum, and the Nrf2 protein increased and the Keap1 protein decreased in synovial tissue. Immunocytochemical staining confirmed that the isolated and cultured cells were AA-FLS; NAC inhibited the proliferation of AA-FLS treated with H2O2 in a concentration-dependent manner, and the mitochondrial ROS content and the protein expressions of Nrf2 and Keap1 decreased. Conclusion NAC can inhibit the proliferation of AA-FLS treated with H2O2, which may be related to blocking Nrf2/Keap1 pathway.
Asunto(s)
Artritis Experimental , Sinoviocitos , Acetilcisteína/farmacología , Animales , Artritis Experimental/tratamiento farmacológico , Proliferación Celular , Fibroblastos/metabolismo , Peróxido de Hidrógeno , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Factor 2 Relacionado con NF-E2/metabolismo , Ratas , Ratas Sprague-Dawley , Sinoviocitos/metabolismoRESUMEN
Molybdenum phosphide in transition metal phosphides members are considered as an attractive electrocatalyst for hydrogen evolution reaction (HER). However, its unsatisfactory stability and conductivity in an alkaline environment has dragged on its development. Here, we successfully introduced N, C co-doped MoP (MoP-NC) nanoparticles by a simple and efficient two-step synthesis method using urea as a carbon source into the molybdenum phosphide system. The cheapness of urea and the excellent carbon to nitrogen ratio remove the obstacles ahead of the development of MoP-NC composites. The obtained composites have excellent HER electrocatalytic activity and stability in 1-M potassium hydroxide (KOH) solution, which requires only an overpotential of 131 mV to achieve a current density of 10 mA cm-2 and exhibits negligible performance degradation after 1000 CV cycles.
RESUMEN
2D materials with direct bandgaps and high carrier mobility are considered excellent candidates for next-generation electronic and optoelectronic devices. Here, a new 2D semiconductor, Na3Sb, is proposed and investigated for the performance limits of FETs by ab initio quantum-transport simulations. Monolayer Na3Sb shows a direct bandgap of 0.89 eV and a high phonon-limited electron mobility of up to 1.25 × 103 cm2 V-1 s-1. We evaluated the impact of channel lengths, gate underlaps, oxide thicknesses, and dielectrics on devices. The major figures of merits for FETs are also assessed in terms of the On-Off ratio, subthreshold swing, gate capacitance, delay time, power dissipation, and field-effect mobility, fulfilling the requirements of the International Roadmap for Devices and Systems (IRDS) for high-performance (HP) devices and demonstrating great potential for electronics with novel 2D Na3Sb.
RESUMEN
The stability and optoelectronic device performance of perovskite quantum dots (Pe-QDs) are severely limited by present ligand strategies since these ligands exhibit a highly dynamic binding state, resulting in serious complications in QD purification and storage. Here, a "Br-equivalent" ligand strategy is developed in which the proposed strong ionic sulfonate heads, for example, benzenesulfonic acid, can firmly bind to the exposed Pb ions to form a steady binding state, and can also effectively eliminate the exciton trapping probability due to bromide vacancies. From these two aspects, the sulfonate heads play a similar role as natural Br ions in a perfect perovskite lattice. Using this approach, high photoluminescence quantum yield (PL QY) > 90% is facilely achieved without the need for amine-related ligands. Furthermore, the prepared PL QYs are well maintained after eight purification cycles, more than five months of storage, and high-flux photo-irradiation. This is the first report of high and versatile stabilities of Pe-QD, which should enable their improved application in lighting, displays, and biologic imaging.
RESUMEN
2D materials are considered as excellent candidates for next-generation electronic and optoelectronic devices. However, the corresponding systems with both an appropriate direct band gap and high carrier mobility are urgently required. Here, a new 2D semiconductor, monolayer RhTeCl, is investigated based on first-principles calculations. Monolayer RhTeCl possesses a direct band gap of 2.16 eV, with a high electron mobility up to 1.5 × 104 cm2 V-1 s-1. Thus, monolayer RhTeCl double-gated metal-oxide-semiconductor field-effect transistors (MOSFETs) with a 6 nm gate length are simulated by quantum transport methods. The 6 nm monolayer RhTeCl n-MOSFET displays a steep sub-kT/q switching characteristic and a high on/off ratio (106), which demonstrates a superior gate control. Therefore, these promising semiconductor characteristics and device performances of 2D RhTeCl provide new opportunities for novel low power ultra-scaled devices.
RESUMEN
Antimonene, a new semiconductor with fundamental bandgap and desirable stability, has been experimentally realized recently. However, epitaxial growth of wafer-scale single-crystalline monolayer antimonene preserving its buckled configuration remains a daunting challenge. Here, Cu(111) and Cu(110) are chosen as the substrates to fabricate high-quality, single-crystalline antimonene via molecular beam epitaxy (MBE). Surface alloys form spontaneously after the deposition and postannealing of Sb on two substrates that show threefold and twofold symmetry with different lattice constants. Increasing the coverage leads to the epitaxial growth of two atomic types of antimonene, both exhibiting a hexagonal lattice but with significant difference in lattice constants, which are observed by scanning tunneling microscopy. Scanning tunneling spectroscopy measurements reveal the strain-induced tunable bandgap, in agreement with the first-principles calculations. The results show that epitaxial growth of antimonene on different substrates allow the electronic properties of these films to be tuned by substrate-induced strain and stress.