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1.
J Endourol ; 2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-32164448

RESUMO

OBJECTIVE: To assess the diagnostic value of transrectal shear wave elastography (SWE) for detecting prostate cancer (PCa) in peripheral zone and compare it with magnetic resonance imaging (MRI). MATERIAL AND METHODS: 221 patients suspected of PCa were enrolled, in which 172 patients of them underwent both SWE and MRI. Elastic value was measured in the area prepared for systematic biopsy and suspicious lesion detected on B-mode or SWE, histopathologic result was compared for each biopsy. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy were derived by obtaining optimal threshold from Receiver operating characteristic (ROC) curve. The correlation between the stiffness of PCa and Gleason scores, Prognostic grades, Percentage of cancer in biopsy were evaluated by Spearman rank correlation. Multivariate logistic regression analysis was performed to determine predictors for diagnosing PCa. The diagnostic capacity of MRI and SWE for detecting PCa and clinically significant PCa in peripheral zone were assessed by comparing area under curve (AUC) of ROC curve. RESULTS: A value of 42kPa was used as the cutoff for differentiating benign from malignant prostatic tissue, the sensitivity, specificity, PPV, NPV and accuracy was 78.97%, 90.67%, 71.30%, 93.66% and 88.03%, respectively. Rank correlation analysis revealed that the stiffness of PCa had a correlation with Gleason score, Prognostic grade and Percentage of cancer in biopsy. On multivariate analysis, the age, free PSA, PSA density, SWE and MRI were independent predictors for diagnosing PCa. There was no statistical difference for diagnosing PCa between SWE and MRI (P=0.259). However, for clinically significant PCa, the diagnostic capacity of SWE were a little higher than MRI(P=0.013). CONCLUSIONS: SWE may provide additional information for PCa detetion, which could increase the positive rate of PCa in targeted biopsy and reduce unnecessary biopsy. SWE is compatible with MRI for detecting PCa in peripheral zone.

2.
Spectrochim Acta A Mol Biomol Spectrosc ; 233: 118172, 2020 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-32135499

RESUMO

In this paper, a series of Eu(III) complexes was designed using 2-thenoyltrifluoroacetone (TTA) as the first ligand, and phenanthroline derivatives as the second ligand. Their molecular structure was analyzed via their single crystals. Detailed photophysical analysis on these Eu(III) complexes suggested that ligand TTA was the major energy transfer antenna for emissive Eu(III). The phenanthroline-derived ligands showed low triplet levels (T1), leading to a reverse energy transfer (triplet trap) from Eu(III) 5D0 to T1 of diamine ligands. This procedure actually compromised emission performance of these Eu(III) complexes. It was found that halogen anions, especially fluorine ion, interacted with these diamine ligands, which heightened triplet level of these diamine ligands. With the elimination of such triplet trap in these Eu(III) complexes, their Eu(III) emission was greatly improved, showing emission turn-on effect. Detailed sensing performance was discussed carefully. Eu(TTA)3Phen showed a down-bending working curve following a two-site model Stern-Volmer equation. Eu(TTA)3DPPZ and Eu(TTA)3DPOX showed linear working curves with good selectivity. In addition to its emission turn-on sensing, Eu(TTA)3DPOX still showed ratiometric sensing. Detailed sensing mechanism was discussed and confirmed.

3.
Sci Total Environ ; 721: 137765, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-32172121

RESUMO

Antibiotics and antibiotic resistance genes (ARGs) in swine wastewater have an irreversible impact on the surrounding water and soil ecosystems. Herein, integrated vertical-flow constructed wetlands (IVCWs) were constructed to assess the effects of zeolite and plants on the removal of sulfonamides (SMs), tetracyclines (TCs), and related ARGs (tetW, tetO, tetM, sul I, sul II, and sul III) from digested swine wastewater. The microorganism community structure was also investigated. Results showed that IVCWs with a zeolite substrate and plant system (ZP) exhibited a favorable removal performance for N, antibiotics, and ARGs at 97.9%, 95.0%, and 95.1%, respectively. Moreover, zeolite systems showed higher adsorption of SMs, lower adsorption of TCs. The higher removal rate of antibiotics in ZP systems might be due to the enhanced microbial degradation with the enrichment of Pseudomonas, Acinetobacter, and Bacillus in zeolite. Furthermore, Arundo donax had limited impact on antibiotics removal and was not conducive to the removal of ARGs. The absolute abundances of sul(I), sul(II), sul(III), tet(M), and tet(O) were significantly positively correlated with the absolute abundance of 16S rDNA. However, no significant correlation was found between the concentration of antibiotics and the abundance of related ARGs in the effluent.

4.
Food Funct ; 11(3): 2067-2079, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32141445

RESUMO

Xanthoceras sorbifolia Bunge is an edible oil tree species peculiar to China and it has long been used as a traditional medicine for enuresis in children. In this study, we investigated the active components in X. sorbifolia and eight barrigenol-type triterpenoids were isolated and identified. All the isolated compounds were tested first for H2O2-induced oxidative stress on human SH-SY5Y cells. Then Y-maze, Morris water maze, novel object recognition and passive avoidance tests were conducted to evaluate the improved effect of selected compounds with neuroprotective activity on ICV Aß1-42 mice. Among all the tested compounds, XS-8 exhibited significant protective effects against learning and memory impairments induced by ICV-Aß1-42. The XS-8 treatment significantly altered Aß-induced hippocampal oxidative defense (increased MDA, nitrite and decreased SOD, glutathione) and pro-inflammatory levels (increased IL-1ß and IL-18). The present study strongly suggests that X. sorbifolia is a promising plant resource for AD use and other neurodegenerative diseases.

5.
Int J Mol Sci ; 21(4)2020 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-32092859

RESUMO

Rice (Oryza sativa L.) frequently suffers in late spring from severe damage due to cold spells, which causes the block of chlorophyll biosynthesis during early rice seedling greening. However, the inhibitory mechanism by which this occurs is still unclear. To explore the responsive mechanism of rice seedlings to low temperatures during greening, the effects of chilling stress on chlorophyll biosynthesis and plastid development were studied in rice seedlings. Chlorophyll biosynthesis was obviously inhibited and chlorophyll accumulation declined under low temperatures during greening. The decrease in chlorophyll synthesis was due to the inhibited synthesis of δ-aminolevulinic acid (ALA) and the suppression of conversion from protochlorophyllide (Pchlide) into chlorophylls (Chls). Meanwhile, the activities of glutamate-1-semialdehyde transaminase (GSA-AT), Mg-chelatase, and protochlorophyllide oxidoreductase (POR) were downregulated under low temperatures. Further investigations showed that chloroplasts at 18 °C had loose granum lamellae, while the thylakoid and lamellar structures of grana could hardly develop at 12 °C after 48 h of greening. Additionally, photosystem II (PSII) and photosystem I (PSI) proteins obviously declined in the stressed seedlings, to the point that the PSII and PSI proteins could hardly be detected after 48 h of greening at 12 °C. Furthermore, the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA) and cell death were all induced by low temperature. Chilling stress had no effect on the development of epidermis cells, but the stomata were smaller under chilling stress than those at 28 °C. Taken together, our study promotes more comprehensive understanding in that chilling could inhibit chlorophyll biosynthesis and cause oxidative damages during greening.

6.
Bioact Mater ; 5(2): 185-191, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32110740

RESUMO

Fused deposition modelling (FDM) is a commonly used 3D printing technology. The development of FDM materials was essential for the product quality of FDM. In this work, a series of polycaprolactone (PCL)-based composites for low-temperature FDM were developed. By melt blending technique, different ratios of starch were added into PCL to improve the performances of FDM, and the printability, tensile strength, rheological properties, crystallization behaviors and biological performances of the composites were studied. The PCL/starch composite had the best performance in FDM process with the starch ratio of 9 ph at 80-90 °C. The melting strength and solidification rate of PCL/starch composites were improved. The starch also increased the crystallization temperature, degree of crystallinity and crystallization rate of PCL/starch composites, while had no negative effects on the tensile strength of PCL. Due to the low printing temperature, various kinds of bioactive components were added into PCL/starch composites for preparation of antibacterial and biocompatible materials for FDM. The present work provides a new method to develop novel low-temperature FDM materials with various functions.

7.
ACS Nano ; 14(2): 2265-2275, 2020 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-32017535

RESUMO

Biomedical device-associated infection (BAI) is a great challenge in modern clinical medicine. Therefore, developing efficient antibacterial materials is significantly important and meaningful for the improvement of medical treatment and people's health. In the present work, we developed a strategy of surface functionalization for multifunctional antibacterial applications. A functionalized polyurethane (PU, a widely used biomedical material for hernia repairing) surface (PU-Au-PEG) with inherent antifouling and photothermal bactericidal properties was readily prepared based on a near-infrared (NIR)-responsive organic/inorganic hybrid coating which consists of gold nanorods (Au NRs) and polyethylene glycol (PEG). The PU-Au-PEG showed a high efficiency to resist adhesion of bacteria and exhibited effective photothermal bactericidal properties under 808 nm NIR irradiation, especially against multidrug-resistant bacteria. Furthermore, the PU-Au-PEG could inhibit biofilm formation long term. The biocompatibility of PU-Au-PEG was also proved by cytotoxicity and hemolysis tests. The in vivo photothermal antibacterial properties were first verified by a subcutaneous implantation animal model. Then, the anti-infection performance in a clinical scenario was studied with an infected hernia model. The results of animal experiment studies demonstrated excellent in vivo anti-infection performances of PU-Au-PEG. The present work provides a facile and promising approach to develop multifunctional biomedical devices.

8.
Chem Biodivers ; 17(2): e1900512, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31900973

RESUMO

Velvet antler (VA) is crucial and precious nourishment in China and some countries in Southeast Asia and has excellent anti-fatigue effect. The incidence of fatigue syndrome has increased gradually. VA can be a potential source of anti-fatigue products. Therefore, we investigated the anti-fatigue activity of different sections (upper, middle, and basal section) of VA from different species (red deer and sika deer) via loading swimming test in mice. Furthermore, nucleosides are one kind of active components in VA which could considerably reduce fatigue in mice. In order to explore whether the nucleosides are correlated with anti-fatigue effect, the contents of eight nucleosides (uracil, cytidine, hypoxanthine, xanthine, thymine, inosine, guanosine, and adenosine) were determined simultaneously using high-performance liquid chromatography. The results indicated that the swimming time in mice was increased from basal to upper section, which was consistent with the change trend of the total contents of eight nucleosides of VA. Therefore, we speculated that the contents of nucleosides in VA may affect its anti-fatigue effect. Furthermore, the contents of nucleosides were also used as a reference for evaluating the quality of different parts of VA obtained from red and sika deer.


Assuntos
Chifres de Veado/metabolismo , Fadiga/tratamento farmacológico , Nucleosídeos/uso terapêutico , Animais , Peso Corporal/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Cervos , Masculino , Camundongos , Nucleosídeos/análise , Nucleosídeos/farmacologia , Condicionamento Físico Animal
9.
J Phys Condens Matter ; 32(19): 195501, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-31958781

RESUMO

Both 2D perovskite Cs2PbI4 and phosphorus are significant optoelectronic semiconductor materials, the optical-electrical characters between both contact interfaces are interesting topics. In present work, we demonstrate comparative investigation of optoelectronic properties for two kinds of electrical contact interfaces. i.e. Pb-I and Cs-I interfaces with black phosphorus contacts. The carrier transport, charge transferring and optical properties for both cases are investigated by using first principle calculation. Both contact interfaces exhibit type II band alignment with direct band gap. Charge carrier migration from Cs-I interface to black phosphorus is more strong than that of Pb-I interface by considering differential charge density and bader charge between distinct electrical contact interfaces. Besides, electron-hole effective masses of heterojunctions for both cases along different direction are investigated. Optical absorption coefficients of both cases are compared with those of free-standing Cs2PbI4 and black phosphorus in the visible spectrum. We systematically compared advantages and disadvantages of two kinds of contact interfaces for photovoltaic application, and the results reveal interfacial engineering of 2D heterojunction plays a important role in tuning optoelectronic properties.

10.
Biomater Sci ; 8(3): 997-1006, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31895368

RESUMO

Catheter-induced infection is a severe problem in clinical practice, which induces significant morbidity, mortality and treatment costs. Therefore, there is a great requirement for developing antibacterial surfaces of catheter materials. In the present study, we develop a strategy for constructing self-adaptive antibacterial surfaces with bacterium-triggered antifouling-bactericidal switching properties on polyurethane (PU) via surface-initiated atom-transfer radical polymerization (SI-ATRP). Polymer coating with one hierarchical structure was readily constructed on the PU surface (PU-PQ-PEG), which was composed of poly[2-(dimethyl decyl ammonium)ethyl methacrylate] (PQDMAEMA) brushes as the bactericidal lower layer and polyethylene glycol (PEG) as the antifouling upper layer. The two layers were incorporated with Schiff base structures, which could be broken by the metabolism of bacteria. Under normal and mild infection conditions, PU-PQ-PEG showed excellent antifouling and biocompatible properties against proteins and bacteria. When serious infection occurred and bacteria colonized on the PU-PQ-PEG surface, the bacteria could trigger the self-adaptive antifouling-bactericidal switching of the surface. Furthermore, the self-adaptive antibacterial properties of PU-PQ-PEG were also confirmed by an in vitro circulating model to simulate hydrodynamic conditions. PU-PQ-PEG showed self-adaptive antibacterial performances both under static and hydrodynamic conditions. The results of animal experiments also demonstrated the in vivo anti-infection performance. The present work will provide a promising strategy for developing antibacterial surfaces of catheter materials with hemocompatibility.

11.
J Phys Condens Matter ; 32(20): 205504, 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31968314

RESUMO

Metal doping, including Bi, Yb, Eu, Sb and so on, are important means to improve the photoelectric properties and stability of metal halide perovskite materials. Among these works, Bi-doped CsPbBr3 especially has attracted much attention for both experimental and theoretical investigation. But there are still some arguments to be solved. One view thinks that Bi doping in CsPbBr3 not only influences the band structure, but also improves the charge transfer (Raihana et al 2017 J. Am. Chem. Soc. 139 731-7). The other supported the points that there are no changes in the valence band structure of Bi-doped CsPbBr3 and the concept of the band-gap engineering in Bi-doped CsPbBr3 halide perovskite is not valid (Olga et al 2018 J. Phys. Chem. Lett. 9 5408-11). They also have different opinions for the reason of the red-shift phenomenon caused by Bi-doped CsPbBr3. In this work, the density functional theory (DFT) based first-principles methods is adopted to investigate the effect of the optical properties and electronic structure for Bi doping CsPbBr3. The calculated results clarify that the red-shift phenomenon is caused by the slight reduction of band gap and the transition levels of Bii and BiPb defects. The values of red-shift also were estimated about 150 meV for Bii defects, which is close the experimental value of about 140 meV. Moreover, our studies also show that the Bi doping does not affect the valence bands, but Bii defects change the electron distribution of the conduction band. Our work and experimental results support and confirm each other, which provides a useful reference for the study of Sb-doped CsPbBr3, Eu-doped CsPbBr3 and so on.

12.
Neurotoxicology ; 76: 144-152, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31722248

RESUMO

BACKGROUND: Aluminum (Al) exerts neurotoxic effects following overexposure. We previously reported worse cognitive performance in workers exposed to Al than non-exposed individuals. Cognition involves multiple domains. The effect of Al on multi-domain cognition has been studied for decades, but still remains controversial. OBJECTIVE: To explore the relationship between plasma Al levels and multi-domain cognitive performance among in-service aluminum-exposed workers at the SH Aluminum Factory in China and identify possible types of early cognitive damage caused by exposure to aluminum. METHODS: Eight hundred thirty-one in-service aluminum-exposed workers at the SH Aluminum Factory in China were investigated. The plasma Al concentrations were measured using inductively coupled plasma-mass spectrometry (ICP-MS) and served as an internal exposure indicator. The participants were divided into four subgroups based on the quartiles of plasma Al concentrations, namely, the Q1, Q2, Q3, and Q4 subgroups. Cognitive function was assessed using the Mini-mental State Examination (MMSE) and the clock-drawing test (CDT). Multi-domain cognition was evaluated using sub-tests of the MMSE and the CDT. RESULTS: The average plasma Al concentration was 15.26 (8.28, 27.02) µg/L. The neurobehavioral tests showed negative correlations between plasma Al levels and total CDT scores and executive/visuospatial cognitive performance, and a positive correlation between plasma Al levels and CDT-position errors (all P<0.05). Additionally, dose-response relationships between higher plasma Al levels and lower total CDT scores, worse executive/visuospatial cognitive performance, and more error rates in the CDT-position were observed (all Ptrend<0.05). However, no significant correlations or trends were observed between plasma Al levels and other cognitive domains (all P>0.05). The results from the multivariate logistic regression model and restricted cubic spline models of dose-response relationships were consistent with the results obtained from the general linear model. All potential confounders, such as age, marital status, education, income, type of work, and smoking and drinking habits, were considered. CONCLUSION: Based on the results, aluminum exposure may exert a substantial effect on impairing executive/visuospatial functions in multi-domain cognition at the early stage, particularly the identification of spatial positions.

13.
Chem Biodivers ; 17(1): e1900516, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31725193

RESUMO

In this study, 13 panaxadiol (PD) derivatives were synthesized via reactions with aromatic compounds and amino acids. Following this, the cytotoxicity of these compounds was evaluated against four cancer cell lines (human hepatoma cells HepG-2, human lung cancer cells A549, human breast cancer cells MCF-7, and human colon cancer cells HCT-116) and one normal cell lines (human gastric epithelial cells GES-1). The results showed that the panaxadiol derivatives 3, 12, and 13 showed significant inhibition of cellular proliferation against cancer cells compared with PD, and the panaxadiol derivative 12 had the lowest IC50 value for A549 (IC50 =18.91±1.03 µm). For MCF-7 cells, most compounds exhibited good inhibition of cellular proliferation, and the panaxadiol derivative 13 showed the strongest inhibitory effect (IC50 =8.62±0.23 µm), which significantly increased the cytotoxicity of PD and was stronger than the positive control (mitomycin). For normal cells, all compounds exhibited low or no toxic effects; thus, these derivatives can be used to develop novel antiproliferative agents.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Ginsenosídeos/química , Ginsenosídeos/farmacologia , Antineoplásicos/química , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Ginsenosídeos/síntese química , Humanos , Estrutura Molecular , Relação Estrutura-Atividade
14.
J Phys Condens Matter ; 32(11): 115703, 2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-31766042

RESUMO

Ultrabroadband mid-frequency infrared photodetectors have important applications in surveillance, medical diagnosis, bioimaging and navigation aids. Thus, researchers hope to detect mid-infrared radiation with larger wavelength. However, due to the limitation of room temperature, it is difficult for these detectors to detect mid-infrared with 4 µm or larger wavelength. Therefore, at room temperature, how to realize mid-infrared detection in a wide range has become an urgent problem to be solved. In this paper, the band structure of SnX2 (X = S,Se)/ZnS and SnS2(1-ŋ)Se2ŋ /ZnS was studied by the density functional theory based first-principles methods. Under the specific stacking procedure, changing the [Formula: see text] of SnS2(1-ŋ)Se2ŋ , the band gap of heterojunctions can be continuously tuned from 0 to 0.97 eV. Amazingly, the band structure maintains the characteristics of a type-II heterojunction. The photodetection in our work is estimated for wavelengths from 1.2 µm to 10 µm, covering a wide wavelength range of mid-infrared. Such a wide range is considerable in current research. The characteristics of type-II band structure and the wide detection range imply that SnX2 /ZnS has great potential in mid-frequency infrared detection. Our work may provide some breakthroughs for the research of multiband photodetectors at room temperature.

15.
J Nat Med ; 74(1): 34-40, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31256310

RESUMO

Four new cucurbitane-type triterpenes were isolated from the fruit of Momordica charantia L. The structures of the new compounds were identified based on HR-ESI-MS and 1D- and 2D-NMR spectroscopic methods. The cytotoxicity of the isolated compounds was evaluated using three human cancer cell lines, HeLa, Caco2, and U87. Compound 3 exhibited significant cytotoxic activity against HeLa cells with an IC50 value of 11.18 µM. Additionally, the cytoprotective activity of these compounds was determined in vitro against H2O2-induced pancreatic injury. The results revealed that all the compounds obtained possess cytoprotective effects against H2O2-induced injury in MIN6 ß-cells at a concentration of 10 µM.

16.
J Nat Med ; 74(1): 41, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31410768

RESUMO

In the original publication of the article, affiliations of authors were published incorrectly. The correct information is provided below.

17.
Eur J Med Chem ; 187: 111964, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31862444

RESUMO

Two series of novel derivatives of AD-2, an active ginsenoside derived from ginseng were designed and synthesized. Five human cancer cell lines (MGC-803, SGC-7901, A549, MCF-7, PC-3 cells) and one normal ovarian cell IOSE144 were employed to evaluate the anti-proliferative activity. Most of derivatives possessed obvious enhanced activity compared with AD-2. Among them, compound 4c displayed the most excellent activity in all tested cancer cell lines, especially A549 cells with an IC50 value of 1.07 ± 0.05 µM. The underlying mechanism study suggested that 4c induced S-phase arrest and apoptosis in A549 cells. Increasing the level of ROS and inducing collapse of MMP in cells treated with 4c were also proved. Moreover, Western blot analysis showed that the expression level of p53 and p21 were obviously increased. 4c could remarkably up-regulate the expression of cyt c in cytosol, the ratio of Bax to Bcl-2 and activate caspase-3/9/PARP. Besides, the expression level of MDM2 was remarkably decreased. The results indicated that 4c caused apoptosis through the mitochondrial pathway, which ROS generation was probably involved in, and had the potent to serve as anti-proliferative agent.


Assuntos
Antimaláricos/farmacologia , Triterpenos/farmacologia , Antimaláricos/síntese química , Antimaláricos/química , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Estrutura Molecular , Relação Estrutura-Atividade , Triterpenos/síntese química , Triterpenos/química , Células Tumorais Cultivadas
18.
J Phys Condens Matter ; 32(6): 065004, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31470426

RESUMO

Recently, the traditional infrared photodetectors (PDs) shows limited application in various areas, due to the narrow band-gap, high cost and even complex manufacturing process. In this situation, scientist have paid much attention to achieve the ultra broadband PDs from the deep ultraviolet to the near infrared. The energy band engineering for two-dimensional (2D) van der Waals heterojunction with free chemical dangling bonds is an effective method to fabricate High-performance Photodetectors. In this work, we employ density functional calculation to construct a type-II CdTe/MoS2 heterostructure and calculate its electronic properties. The results reveal that the CdTe/MoS2 has the narrow band gap of 0.64 eV and electrons transfer from the CdTe to MoS2 layer, which promotes the separation of photogenerated carriers and enhance the photoelectron conversion efficiency. Driven by the smaller band gap, it can respond to near infrared, visible and ultraviolet light, demonstrating it the promising application for solar cell. Furthermore, the analysis of molecules adsorption and band edge alignment indicates that the CdTe/MoS2 is prone to capture H2O and release the H2 molecules, which is conductive to the photocatalytic water splitting for hydrogen generation. Our work suggests that the CdTe/MoS2 heterostructure is a potential candidate as a solar cell and even photocatalyst, and also provides a new sight for experimental and theoretical research to design a highly efficient device.

19.
Nanoscale ; 12(2): 1061-1066, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31845937

RESUMO

Platinum diselenide (PtSe2), a type-II Dirac semi-metal material, is a potential saturable absorber (SA) to generate visible pulsed lasers due to its prominent optoelectronic properties. A high quality PtSe2 thin film was fabricated by combining magnetron sputtering with chemical vapor deposition methods; then, its microtopography was characterized by atomic force microscopy. The saturable absorption properties and electron relaxation time in the visible region were measured via open-aperture Z-scan and femtosecond pump probe technology, respectively. The modulation depth and saturable intensity are 39.9% and 256.6 GW cm-2, respectively. The relaxation time constants were fitted to be τ1 = (1.405 ± 0.024) ps, τ2 = (99.03 ± 0.01) ps, and τ3 = (2.032 ± 0.27) ns. The as-prepared PtSe2 thin film was experimentally applied as a novel SA to achieve a stable passively Q-switched (PQS) Pr:YLF visible laser. A shortest pulse width of 91.8 ns with a maximum repetition rate of 297.6 kHz was obtained. These results demonstrate that the PtSe2 thin film has promising applications in generating visible pulsed lasers.

20.
J Phys Condens Matter ; 32(6): 065002, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31648212

RESUMO

Electroluminescence devices based on all-inorganic halide perovskite material with excellent luminescence performance have been studied extensively in recent years. However, the important role for the electrodes of electroluminescence devices is payed few attention by theoretical and experimental studies. Appropriate electrodes can reduce the Schottky barrier height to decrease the energy loss, and prevent the metal impurities from diffusing into the perovskite material to generate deep traps levels, which improves the luminous efficiency and lifetime of devices. In this paper, not only the interface effects between CsPbBr3 and common metal electrode (Ag, Au, Ni, Cu and Pt) are studied by first-principle calculations, but also the diffusion effects of metal electrode atom into the CsPbBr3 layer are also explored by nudged elastic band calculations. The calculated results show the metal Ag is more suitable for the cathode for CsPbBr3 electroluminescence devices, while the metal Pt is more applicable for the anode. Based on the overall consideration about the interface effects and diffusion effects of the CsPbBr3-metal electrode junctions, the essential principle is analyzed. The work provides theoretical guidance for how to select the right electrode for the electroluminescence performance of all-inorganic halide perovskite. The critical factor of Schottky barrier height between the electrode and the light-emitting semiconductor, and transition level generated by metal impurities also provide a valuable reference how to select the suitable electrodes for other electroluminescence devices.

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