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1.
BMC Geriatr ; 24(1): 181, 2024 Feb 23.
Article En | MEDLINE | ID: mdl-38395763

PURPOSE: Sarcopenia is a pathological change characterized by muscle loss in older people. According to the reports, there is controversy on the relationship between dyslipidemia and sarcopenia. Therefore, this meta-analysis aimed to explore the association between sarcopenia and dyslipidemia. METHODS: We searched the Cochrane Library, Web of Science, PubMed, China National Knowledge Infrastructure (CNKI), Wan Fang, China Science and Technology Journal Database (VIP Database) for case‒control studies to extract data on the odds ratio (OR) between sarcopenia and dyslipidemia and the MD(mean difference) of TC, LDL-C, HDL-C, TG, and TG/HDL-C between sarcopenia and nonsarcopenia. The JBI(Joanna Briggs) guidelines were used to evaluate the quality. Excel 2021, Review Manager 5.3 and Stata 16.0 were used for the statistical analysis. RESULTS: Twenty studies were included in the meta-analysis, 19 of which were evaluated as good quality. The overall OR of the relationship between sarcopenia and dyslipidemia was 1.47, and the MD values of TC, LDL-C, HDL-C, TG, and TG/HDL-C were 1.10, 1.95, 1.27, 30.13, and 0.16 respectively. In female, compared with the non-sarcopnia, the MD of TC, LDL-C, HDL-C, TG of sarcopenia were - 1.67,2.21,1.02,-3.18 respectively. In male, the MD of TC, LDL-C, HDL-C, TG between sarcopenia and non-sarcopenia were - 0.51, 1.41, 5.77, -0.67. The OR between sarcopenia and dyslipidemia of the non-China region was 4.38, and it was 0.9 in China. In the group(> 60), MD of TC between sarcopenia and non-sarcopenia was 2.63, while it was 1.54 in the group(20-60). CONCLUSION: Dyslipidemia was associated with sarcopenia in the elderly, which was affected by sex, region and age.


Dyslipidemias , Sarcopenia , Humans , Male , Female , Aged , Cholesterol, LDL , Sarcopenia/diagnosis , Sarcopenia/epidemiology , Sarcopenia/complications , Dyslipidemias/diagnosis , Dyslipidemias/epidemiology , Dyslipidemias/complications , Case-Control Studies , China , Triglycerides
2.
J. physiol. biochem ; 80(1): 137-147, Feb. 2024. graf
Article En | IBECS | ID: ibc-229946

We aimed to determine whether quercetin is capable of improving circadian rhythm and metabolism disorder under vitamin D-deficient condition. Middle-aged mice were randomly divided into four groups, namely, control (CON), vitamin D-deficient diet (VDD), quercetin (Q), and quercetin intervention in vitamin D-deficient diet (VDQ), with a total of 12 weeks’ intervention. Mice were sacrificed at zeitgeber time1 (ZT1) and ZT13 time points. At ZT1, circadian locomotor output cycle kaput (CLOCK) protein expression from VDD, Q, and VDQ groups; CRY1 from Q group; and CRY2 from VDD group were significantly lower compared to CON group. The mRNA expression of Sirt1, Bmal1, Clock, Cry1, and Cry2 in VDQ groups, also Bmal1, Clock, and Cry1 from Q group, were significantly decreased compared to CON group. At ZT13, compared to CON group, fasting insulin and homeostasis model assessment-insulin resistance (HOMA-IR) were higher in VDD group; BMAL1 was significantly increased, while CLOCK and CRY1 protein were significantly decreased from VDD group; CLOCK protein from VDQ group was significantly higher compared to CON, VDD, and Q groups, and also, BMAL1 protein expression from VDQ group was elevated compared to CON group. The mRNA expression of Bmal1, Clock, Per2, Cry1, and Cry2 in VDQ groups were significantly increased compared to CON groups. The mRNA expression of Bmal1 from VDQ group was decreased compared to both VDD and Q group. In conclusion, vitamin D-deficient diet resulted in a disordered liver circadian rhythm, and quercetin improved the hepatic circadian desynchronization. Quercetin supplementation might be effective for balancing circadian rhythm under vitamin D-deficient condition. (AU)


Animals , Mice , Vitamin D Deficiency , Quercetin/pharmacology , Circadian Rhythm/drug effects , Insulin Resistance
3.
J. physiol. biochem ; 80(1): 137-147, Feb. 2024. graf
Article En | IBECS | ID: ibc-EMG-572

We aimed to determine whether quercetin is capable of improving circadian rhythm and metabolism disorder under vitamin D-deficient condition. Middle-aged mice were randomly divided into four groups, namely, control (CON), vitamin D-deficient diet (VDD), quercetin (Q), and quercetin intervention in vitamin D-deficient diet (VDQ), with a total of 12 weeks’ intervention. Mice were sacrificed at zeitgeber time1 (ZT1) and ZT13 time points. At ZT1, circadian locomotor output cycle kaput (CLOCK) protein expression from VDD, Q, and VDQ groups; CRY1 from Q group; and CRY2 from VDD group were significantly lower compared to CON group. The mRNA expression of Sirt1, Bmal1, Clock, Cry1, and Cry2 in VDQ groups, also Bmal1, Clock, and Cry1 from Q group, were significantly decreased compared to CON group. At ZT13, compared to CON group, fasting insulin and homeostasis model assessment-insulin resistance (HOMA-IR) were higher in VDD group; BMAL1 was significantly increased, while CLOCK and CRY1 protein were significantly decreased from VDD group; CLOCK protein from VDQ group was significantly higher compared to CON, VDD, and Q groups, and also, BMAL1 protein expression from VDQ group was elevated compared to CON group. The mRNA expression of Bmal1, Clock, Per2, Cry1, and Cry2 in VDQ groups were significantly increased compared to CON groups. The mRNA expression of Bmal1 from VDQ group was decreased compared to both VDD and Q group. In conclusion, vitamin D-deficient diet resulted in a disordered liver circadian rhythm, and quercetin improved the hepatic circadian desynchronization. Quercetin supplementation might be effective for balancing circadian rhythm under vitamin D-deficient condition. (AU)


Animals , Mice , Vitamin D Deficiency , Quercetin/pharmacology , Circadian Rhythm/drug effects , Insulin Resistance
4.
J Physiol Biochem ; 80(1): 137-147, 2024 Feb.
Article En | MEDLINE | ID: mdl-37948027

We aimed to determine whether quercetin is capable of improving circadian rhythm and metabolism disorder under vitamin D-deficient condition. Middle-aged mice were randomly divided into four groups, namely, control (CON), vitamin D-deficient diet (VDD), quercetin (Q), and quercetin intervention in vitamin D-deficient diet (VDQ), with a total of 12 weeks' intervention. Mice were sacrificed at zeitgeber time1 (ZT1) and ZT13 time points. At ZT1, circadian locomotor output cycle kaput (CLOCK) protein expression from VDD, Q, and VDQ groups; CRY1 from Q group; and CRY2 from VDD group were significantly lower compared to CON group. The mRNA expression of Sirt1, Bmal1, Clock, Cry1, and Cry2 in VDQ groups, also Bmal1, Clock, and Cry1 from Q group, were significantly decreased compared to CON group. At ZT13, compared to CON group, fasting insulin and homeostasis model assessment-insulin resistance (HOMA-IR) were higher in VDD group; BMAL1 was significantly increased, while CLOCK and CRY1 protein were significantly decreased from VDD group; CLOCK protein from VDQ group was significantly higher compared to CON, VDD, and Q groups, and also, BMAL1 protein expression from VDQ group was elevated compared to CON group. The mRNA expression of Bmal1, Clock, Per2, Cry1, and Cry2 in VDQ groups were significantly increased compared to CON groups. The mRNA expression of Bmal1 from VDQ group was decreased compared to both VDD and Q group. In conclusion, vitamin D-deficient diet resulted in a disordered liver circadian rhythm, and quercetin improved the hepatic circadian desynchronization. Quercetin supplementation might be effective for balancing circadian rhythm under vitamin D-deficient condition.


Circadian Clocks , Liver Diseases , Mice , Animals , Quercetin/pharmacology , Quercetin/therapeutic use , ARNTL Transcription Factors/genetics , Vitamin D/therapeutic use , Circadian Rhythm/genetics , CLOCK Proteins/genetics , RNA, Messenger/genetics , RNA, Messenger/metabolism , Diet
5.
Angew Chem Int Ed Engl ; 63(1): e202316384, 2024 Jan 02.
Article En | MEDLINE | ID: mdl-38009454

Photocatalytic nitrogen fixation using solar illumination under ambient conditions is a promising strategy for production of the indispensable chemical NH3 . However, due to the catalyst's limitations in solar energy utilization, loss of hot electrons during transfer, and low nitrogen adsorption and activation capacity, the unsatisfactory solar-to-chemical conversion (SCC) efficiencies of most photocatalysts limit their practical applications. Herein, cerium oxide nanosheets with abundant strain-VO defects were anchored on Au hollow nanomushroom through atomically sharp interfaces to construct a novel semiconductor/plasmonic metal hollow nanomushroom-like heterostructure (denoted cerium oxide-AD/Au). Plasmonic Au extended the absorption of light from the visible to the second near-infrared region. The superior interface greatly enhanced the transfer efficiency of hot electrons. Abundant strain-VO defects induced by interfacial compressive strain promoted adsorption and in situ activation of nitrogen, and such synergistic promotion of strain and VO defects was further confirmed by density functional theory calculations. The judicious structural and defect engineering co-promoted the efficient nitrogen photofixation of the cerium oxide-AD/Au heterostructures with a SCC efficiency of 0.1 % under simulated AM 1.5G solar illumination, which is comparable to the average solar-to-biomass conversion efficiency of natural photosynthesis by typical plants, thus exhibiting significant potential as a new candidate for artificial photosynthesis.

6.
JACS Au ; 3(7): 1851-1863, 2023 Jul 24.
Article En | MEDLINE | ID: mdl-37502161

Monoclinic BiVO4 is one of the most promising photoanode materials for solar water splitting. The photoelectrochemical performance of a BiVO4 photoanode could be significantly influenced by the noncovalent interactions of redox-inert metal cations at the photoanode-electrolyte interfaces, but this point has not been well investigated. In this work, we studied the Cs+-dependent surface reconstruction and passivation of BiVO4 photoanodes. Owing to the "structure breaker" nature of Cs+, the Cs+ at the BiVO4 photoanode-electrolyte interfaces participated in BiVO4 surface photocorrosion to form a Cs+-doped bismuth vanadium oxide amorphous thin layer, which inhibited the continuous photocorrosion of BiVO4 and promoted surface charge transfer and water oxidation. The resulting cocatalyst-free BiVO4 photoanodes achieved 3.3 mA cm-2 photocurrent for water oxidation. With the modification of FeOOH catalysts, the photocurrent at 1.23 VRHE reached 5.1 mA cm-2, and a steady photocurrent of 3.0 mA cm-2 at 0.8 VRHE was maintained for 30 h. This work provides new insights into the understanding of Cs+ chemistry and the effects of redox-inert cations at the electrode-electrolyte interfaces.

7.
Oxid Med Cell Longev ; 2023: 2766250, 2023.
Article En | MEDLINE | ID: mdl-36713033

Gut microbes may be the critical mediators for the cognitive enhancing effects of exercise. Via fecal microbiota transplantation (FMT), this study is aimed at determining the mechanism of how voluntary exercise improved learning and memory ability impairment post a high-fat, high-cholesterol (HFHC) diet. The learning and memory abilities assessed via the Morris water maze in the FMT recipient group of voluntary exercising mice were improved compared to sedentary group. 16S rRNA gene sequencing results indicated that exercise-induced changes in gut microbiota distribution were transmissible, mainly in terms of elevated Lactobacillus, Lactobacillus, and Eubacterium nodatum, as well as decreased Clostrida_UCG-014 and Akkermansia after FMT. The neuroprotective effects of FMT were mainly related to the improved insulin signaling pathway (IRS2/PI3K/AKT) and mitochondrial function; inhibition of AQP4; decreased p-Tau at serine 396 and 404; increased BDNF, PSD95, and synaptophysin in the hippocampus; and also decreased HDAC2 and HDAC3 protein expressions in the nuclear and cytoplasmic fractions of the hippocampus. The findings of qRT-PCR suggested that exercise-induced gut microbes, on the one hand, elevated GPR109A and decreased GPR43 and TNF-α in the hippocampus. On the other hand, it increased GPR109A and GPR41 expressions in the proximal colon tissue. In addition, total short-chain fatty acid (SCFA), acetic acid, propionic acid, isobutyric acid, valeric acid, and isovaleric acid contents were also elevated in the cecum. In conclusion, exercise-induced alterations in gut microbiota play a decisive role in ameliorating HFHC diet-induced cognitive deficits. FMT treatment may be a new considerable direction in ameliorating cognitive impairment induced by exposure to HFHC diet.


Cognitive Dysfunction , Gastrointestinal Microbiome , Animals , Mice , Cholesterol/pharmacology , Cognitive Dysfunction/therapy , Diet, High-Fat/adverse effects , Mice, Inbred C57BL , Phosphatidylinositol 3-Kinases , RNA, Ribosomal, 16S , Physical Conditioning, Animal
8.
Neurochem Int ; 162: 105459, 2023 01.
Article En | MEDLINE | ID: mdl-36460238

To determine whether trimethylamine N-oxide (TMAO) would aggravate cognitive dysfunction from APP/PS1 mice and the potential protective effects of voluntary wheel running (VWR). TMAO impaired learning and memory abilities, and exercise reversed TMAO induced cognitive impairment. Serum TMAO, choline, betaine and TMA were significantly elevated from TMAO group, while exercise group had decreased TMAO, betaine and TMA level. TMAO group has significantly upregulated BACE1 from both hippocampus and cortex, also increased cathepsin B, p-Tau at Ser396&Ser404, GFAP, p-NF-κB p65 in cortex, while reduced BDNF, synaptophysin and PSD95 in hippocampus, also reduced occludin and ZO-1 from cortex, and reduced occludin from colon. In contrast, BACE1 from both hippocampus and cortex, also cathepsin B and p-Tauser396 from cortex were reduced, BDNF, snaptophysin, and PSD95 from hippocampus, ZO-1 from cortex, and occludin from colon were elevated post exercise compared to TMAO group. Exercise elevated α diversity index of cecal content, and TMAO and exercise affected gut microbiota profiles differentially. In conclusion, TMAO led to gut microbiota dysbiosis, impaired gut-brain integrity, elevated neuroinflammation, Aß pathology and tau phosphorylation, disordered synaptic function; and exercise could reverse TMAO induced cognitive dysfunction via improving the above markers. The potential deleterious effects of TMAO on cognitive function need to be validated in humans, also dosages of exercise for exerting neuroprotective effects against TMAO induced cognitive impairment.


Cognitive Dysfunction , Exercise , Animals , Mice , Amyloid Precursor Protein Secretases , Aspartic Acid Endopeptidases , Betaine , Brain-Derived Neurotrophic Factor , Cathepsin B , Choline , Cognitive Dysfunction/chemically induced , Motor Activity , Occludin , Exercise/physiology
9.
J Phys Chem Lett ; 13(13): 3072-3078, 2022 Apr 07.
Article En | MEDLINE | ID: mdl-35353521

Coherent phonons generated through regulation of lattice oscillation via ultrafast laser pulses or X-rays have been desired in various fields, including optoelectronics, thermal and quantum information, and communications. Phonon coherence of two-dimensional (2D) materials is particularly attractive as it enables controllable information transmission but is challenging as the weak interplanar coupling makes phonon excitation extremely difficult. Herein we managed to generate size-dependent phonon coherence from bulk Bi to few-layer bismuthene by an ultrafast femtosecond laser pulse and made a systematic comparison thorough a combination of computation, transient absorption, and reflectance spectroscopic methods. The results witnessed the A1g phonon excitation in all of the three Bi materials with distinct thicknesses, and the quantum size effect of 2D materials caused phonon confinement and eventual bond softening manifested as a red-shifted vibration frequency and shortened decoherence time compared with those of their bulk counterpart. This study offers new perspectives for tailoring coherent phonons in 2D materials for quantum science and technology including quantum communication, computing, and design of novel quantum devices, etc.

10.
Ecotoxicol Environ Saf ; 229: 113092, 2022 Jan 01.
Article En | MEDLINE | ID: mdl-34922169

Soil pollution is a serious threat to human life and development. Different remedial measures are applied to soils with different levels of contamination. The degree of soil contamination in different areas is generally evaluated and categorised based on the analysis of samples. Regional soil sampling sites are generally sparse because of the cost of sampling and other factors, which makes it difficult to accurately assess the extent of regional soil contamination. In this study, a spatial classification model was established for the Di(2-ethylhexyl) phthalate (DEHP) pollution level using a Bi-directional Long Short-Term Memory (Bi-LSTM) neural network considering that the sampling information gradually diminishes with increasing distance between the sampling and prediction points. In this study, a method is proposed for the prediction of the spatial distribution of soil pollution categories based on sparse samples. We also established a model for the spatial distribution of organic pollution categories. The analysis of an actual contaminated area shows that the DEHP concentrations at different locations can be effectively predicted with the proposed method by categorising the contamination levels of specific DEHP samples. The results show that the method can be used to classify the degree of light/severe DEHP contamination. The results are in good agreement with the actual situation, verifying the validity of the method. This method is important for the rapid assessment of the spatial distribution of soil contamination levels based on sparse sampling.


Diethylhexyl Phthalate , Phthalic Acids , Soil Pollutants , Environmental Pollution , Esters , Humans , Soil , Soil Pollutants/analysis
11.
Nanoscale ; 13(36): 15301-15310, 2021 Sep 23.
Article En | MEDLINE | ID: mdl-34490860

"Giant" core/shell quantum dots (g-QDs) are promising candidates for emerging optoelectronic technologies thanks to their facile structure/composition-tunable optoelectronic properties and outstanding photo-physical/chemical stability. Here, we synthesized a new type of CuInTeSe (CITS)/CdS g-QDs and regulated their optoelectronic properties by controlling the shell thickness. Through increasing the shell thickness, as-prepared g-QDs exhibited tunable red-shifted emission (from 900 to 1200 nm) and prolonged photoluminescence (PL) lifetimes (up to ∼14.0 µs), indicating a formed band structure showing efficient charge separation and transfer, which is further testified by theoretical calculations and ultrafast time-resolved transient absorption (TA) spectroscopy. These CITS/CdS g-QDs with various shell thicknesses can be employed to fabricate photoelectrochemical (PEC) cells, exhibiting improved photoresponse and stability as compared to the bare CITS QD-based devices. The results indicate that the rational design and engineering of g-QDs is very promising for future QD-based optoelectronic technologies.

12.
ACS Omega ; 6(34): 21915-21924, 2021 Aug 31.
Article En | MEDLINE | ID: mdl-34497887

To fully utilize the forestry bioresources, a novel dual-cross-linkable resin monomer of MAHSWAGMA was prepared from Swida wilsoniana oil (SWO). FT-IR and 1H-NMR analysis demonstrated the successful synthesis of the target product. Five different cross-linking copolymers, including a polymerized vinyl ester/single-cross-linking (PVESC) polymer, a polymerized epoxy/single-cross-linking (PESC) copolymer, a thermal-photo-initiated/dual-cross-linking (TPIDC) copolymer, a photo-thermal-initiated/dual-cross-linking copolymer (PTIDC), and a thermal-initiated/dual-cross-linking copolymer (TIDC), were obtained with different preparation technologies by different initiated cross-linking processes. Thermal and mechanical properties of the five copolymers were all tested, and the effects of different preparation technologies on the properties of prepared copolymers were investigated. The prepared three dual-cross-linking copolymers had higher hardness, relative cross-linking density, glass transition temperature, and more excellent mechanical property than the other two single-cross-linking copolymers. The PTIDC copolymerized system obtained with photo first and thermal latter initiated dual-cross-linking preparation technology had the most excellent comprehensive properties. This study can provide an ideal idea for the design and preparation of dual-cross-linking copolymers based on forestry vegetable oil.

13.
Nanoscale Horiz ; 5(10): 1420-1429, 2020 Oct 01.
Article En | MEDLINE | ID: mdl-32856666

Sb nanosheets, also known as antimonene, have received ever-growing consideration as a promising new type of two-dimensional (2D) material due to their many attractive properties. However, how their nonlinear optical (NLO) properties are affected by their nanosheet structure and measurement conditions remains unclear. Herein, we report a successful size-selective production method for Sb nanosheets, which is based on a combination of lithium ion intercalation, solvent exfoliation and size selection centrifugation. This high-yield and size-selective preparation method enables fundamental investigation on the relation of the intrinsic optical properties of Sb nanosheets. Nanosecond Z-scan measurements revealed a unique size-dependent broadband NLO response. When the average size is reduced from 3 micrometers to 50 nanometers, the Sb nanosheets exhibit a clear transition from saturable absorption to reversed saturable absorption. Ultrafast transient absorption spectroscopic investigation indicated that exciton cooling is significantly faster in a small nanosheet than in large ones, revealing that the different exciton relaxation dynamic plays key roles in the distinct size-tunable nonlinear optical response. This work paves new ways towards the mass production and practical application of antimonene.

14.
J Phys Chem Lett ; 11(15): 6007-6015, 2020 Aug 06.
Article En | MEDLINE | ID: mdl-32628484

Two-dimensional (2D) CsPb2Br5 exhibits intriguing functions in enhancing the performance of optoelectronic devices in terms of environmental stability and luminescence properties when composited with other perovskites in different dimensionalities. We built a type I three-dimensional (3D) CsPbBr3/2D CsPb2Br5 heterojunction through phase transition where CsPbBr3 quantum dots in situ grew into 2D CsPb2Br5. A thorough growth mechanism study in combination with excited state dynamic investigations via femtosecond spectroscopy and first-principles calculations revealed that the type I hierarchy enhanced the stability of the heterojunction and spurred its luminous quantum yield by prolonging the lifetime of photogenerated carriers. Mixing the heterojunction with other phosphors yielded white-light-emitting diodes with a color rendering index of 94%. The work thus not only offered one new avenue for building heterojunctions by using the "soft crystal" nature of perovskites but also disentangled the enhanced luminescence mechanism of the heterojunction that can be harnessed for promising applications in the luminescence and display fields.

15.
Nanoscale ; 12(10): 6195-6203, 2020 Mar 12.
Article En | MEDLINE | ID: mdl-32133481

Vertical heterojunctions of two-dimensional (2D) semiconducting materials have attracted more and more research interest recently due to their unique optical, electrical, and catalytic properties and potential applications. Although great progress has been made, vertical integration of the layered materials formed by 2D semiconductor nanosheets and 2D plasmatic metal nanosheets remains a huge challenge. Here, we demonstrate for the first time a solution-phase growth of vertical plasmatic metal-semiconductor heterostructures in which aligned NiCo2O4 nanosheet arrays vertically grow on a single Au nanosheet, forming vertically aligned NiCo2O4-Au-NiCo2O4 sandwich-type heterojunctions with hierarchical open channels. Such vertical NiCo2O4-Au-NiCo2O4 heterojunctions can effectively promote the separation and transfer of a photoinduced charge. Density functional theory (DFT) studies and time-resolved transient absorption spectroscopy show that electrons transfer from NiCo2O4 to Au, and the formation of the heterojunction weakens the H-O bond of H2O. Due to the unique structure and superiority of the component, the vertical NiCo2O4-Au-NiCo2O4 heterojunctions exhibit significant activity with an O2 production rate of up to 33 µmol h-1 and long-term stability for photocatalytic water oxidation. We calculated the apparent quantum efficiency (AQE) to be 21.9% for NiCo2O4-Au-NiCo2O4 heterojunctions at the wavelength λ = 450 ± 10 nm, which is higher than that of NiCo2O4 nanosheets (10.9%), Au nanosheets (0.96%) and other photocatalysts. The present study paves the way for the controlled synthesis of novel vertical heterojunctions based on 2D semiconductor nanosheets and 2D metal nanosheets for efficient photocatalysis.

16.
ACS Appl Mater Interfaces ; 11(43): 40014-40021, 2019 Oct 30.
Article En | MEDLINE | ID: mdl-31603643

The excellent light absorption, low electron-hole recombination rate, and fast reaction kinetics of photogenerated charges are urgently needed for photoelectrochemical (PEC) water splitting. Herein, a novel p-n heterostructure photoelectrode (ReS2/Ni3S2) is constructed via a one-step hydrothermal method, which shows remarkable HER activity under illumination such as a low overpotential (η10) of 106 mV, high IPCE of 10-15%, and good stability. High-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) reveal that the intimate interface and strong electron interaction between ReS2 and Ni3S2 can enhance the light adsorption and provide abundant active sites. The transient absorption (TA) spectroscopy and impedance spectroscopy analyses (EIS) demonstrate the prolonged carrier lifetime and fast charge transfer. All of these are responsible for the improvement of reaction kinetics. This work provides a brand new avenue to explore efficient photoelectrocatalysts for water splitting.

17.
J Phys Chem Lett ; 10(21): 6572-6577, 2019 Nov 07.
Article En | MEDLINE | ID: mdl-31594309

New all-inorganic perovskites like Cs4PbBr6 provide rich luminescent tools and particularly novel physical insights, including their zero-dimensional structure and controversial emitting mechanism. The ensuing debate over the origin of the luminescence of Cs4PbBr6 inspired us to tackle the issue through fabricating high-quality Cs4PbBr6 single crystals and employing ultrafast dynamics study. Upon photoexcitation, Cs4PbBr6 underwent dynamics steps distinct from that of CsPbBr3, including exciton migration to the defect level on a time scale of several hundred femtoseconds, exciton relaxation within the defect states on the picosecond time scale, and exciton recombination from the subnanosecond to nanosecond time scale. The observation disclosed that crystal defects of Cs4PbBr6 induced green emission while CsPbBr3 mainly relied on quantum confinement to emit at room temperature. The study provides an in-depth understanding of the photoinduced multistep dynamics steps of Cs4PbBr6 associated with display and photovoltaic applications, establishing Cs4PbBr6 as a new candidate for uses associated with the perovskite family of materials.

18.
Chem Commun (Camb) ; 55(74): 11056-11058, 2019 Sep 12.
Article En | MEDLINE | ID: mdl-31453575

Natural hollow fibers were used as templates to in situ produce thin Cs4PbX6 nanosheets on the inner walls, forming luminescent fibers that integrated the advantages of the large length of fibers and the emission tunability of perovskites, and exhibited great robustness as well for multiple applications like warning signs, anti-counterfeiting and fashion.

19.
Nanoscale ; 10(45): 21106-21115, 2018 Dec 07.
Article En | MEDLINE | ID: mdl-30325397

The rediscovery of black phosphorus (BP) has expanded the 2D family into Group 15 (Nitrogen Group) elements, among which bismuthene is the latest member with extraordinary opto-electronic, catalytic and biocompatible properties and potential as a 2D topological insulator. However, bulk Bi is not easily mechanically exfoliated as its counterpart of BP. Thus, to date, the reports on 2D Bi fabrication are rare, and investigations on its nonlinear optical properties are even less. Herein, we rationally designed a new strategy combining acid-interaction and liquid exfoliation to successfully transform metal bulk Bi into few-layer semiconductor, which resulted in unseen opto-electronic properties, such as tunable nonlinear responses all the way to the near-infrared (NIR) region. This band is critical for telecommunication and military purposes, but currently, functioning materials are extremely scarce. The origin of this strong saturable absorption was thoroughly explored through time-resolved spectroscopy spanning from the fs to µs timescale, which indicated ultrafast fs to ps carrier dynamics in the early stage and long exciton bleaching recovery up to µs. As a proof-of-concept application, the as-prepared 2D Bi was employed as a saturable absorber to mode-lock a Tm-doped fiber laser and successfully realized a 2 µm NIR-wavelength output. This study not only offers an effective and scalable method to fabricate the new 2D family member bismuthene with extraordinary stability, but also explores its strong and broad nonlinear responses extending into the NIR region and fundamental photoinduced dynamics, which demonstrate the full potential of 2D Bi for application in opto-electronic devices and nonlinear optics.

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