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ObjectiveInnate immunity plays important roles in pancreatic ductal adenocarcinoma (PDAC), as non-T-cell-enriched tumour. Neutrophils are major players in innate immune system. Here, we aimed to explore the heterogeneity and pro-tumour mechanisms of neutrophils in PDAC.DesignWe analysed single-cell transcriptomes of peripheral blood polymorphonuclear leucocytes (PMNs) and tumour-infiltrating immune cells from five patients with PDAC, and performed immunofluorescence/immunohistochemistry staining, multi-omics analysis andin vitroexperiments to validate the discoveries of bioinformatics analysis.ResultsExploration of the heterogeneity of tumour-associated neutrophils (TANs) revealed a terminally differentiated pro-tumour subpopulation (TAN-1) associated with poor prognosis, an inflammatory subpopulation (TAN-2), a population of transitional stage that have just migrated to tumour microenvironment (TAN-3) and a subpopulation preferentially expressing interferon-stimulated genes (TAN-4). Glycolysis signature was upregulated along neutrophil transition trajectory, and TAN-1 was featured with hyperactivated glycolytic activity. The glycolytic switch of TANs was validated by integrative multi-omics approach of transcriptomics, proteomics and metabolomics analysis. Activation of glycolytic activity by LDHA overexpression induced immunosuppression and pro-tumour functions in neutrophil-like differentiated HL-60 (dHL-60) cells. Mechanistic studies revealed BHLHE40, downstream to hypoxia and endoplasmic reticulum stress, was a key regulator in polarisation of neutrophils towards TAN-1 phenotype, and direct transcriptional regulation of BHLHE40 on TAN-1 marker genes was demonstrated by chromatin immunoprecipitation assay. Pro-tumour and immunosuppression functions were observed in dHL-60 cells overexpressing BHLHE40. Importantly, immunohistochemistry analysis of PDAC tissues revealed the unfavourable prognostic value of BHLHE40+neutrophils.ConclusionThe dynamic properties of TANs revealed by this study will be helpful in advancing PDAC therapy targeting innate immunity.

Schottky-contacted nanosensors have attracted extensive attention due to their high sensitivity and fast response time. In this article, we proved that the construction of Schottky contact by Pt nanoparticles (NPs) decoration can effectively improve the performance of V2O5 nanobelts photodetectors. After modified by Pt NPs, the photocurrent of V2O5 nanobelts is increased by more than two orders of magnitude, and the photoresponse speed is improved by at least three orders of magnitude. Detailed studies have shown that the performance enhancement is attributed to the formation of the Schottky contact at the electrode-semiconductor interface due to the decrease of surface gas adsorption and the increase of V2O5 work function after Pt NPs modification. The strong built-in field in the Schottky barrier region will quickly separate photogenerated carriers, thereby reducing the electron-hole recombination rate, resulting in the fast response time and an increase in the free carrier density. Moreover, it is found that this enhancement effect can be regulated by controlling the pressure to modulating the Schottky barrier height at the interface. Overall, the Pt NPs-modified V2O5 nanobelts photodetector exhibits a broad response spectrum (visible to near infrared), fast rise/fall response time (less than 6.12/6.15 ms), high responsivity (5.6 A/W), and high specific detectivity (6.9 × 108 Jones). This study demonstrates the feasibility of building a Schottky barrier to enhance the photodetection performance, which provides a general and effective strategy towards the construction and its practical application of supersensitive and fast-response nanosensors.

VO2(B) is a metastable phase of VO2 composed of both edge-sharing and corner sharing irregular VO6 octahedrons. VO2(B) is a metallic phase at room temperature, and shows large tunnels in the lattices that allows rapid intercalation and deintercalation of metal ions. It also shows high temperature coefficient of resistance (TCR) and low 1/f noise with appropriate resistance. These merits attract much attention in the field of metal ion battery and uncooled infrared detectors. Here we will give a systematically review on the advances in development of preparation and applications of VO2(B). We focus on the structure and properties of VO2(B) that strongly affects the application in metal ion battery and uncooled infrared detectors, and the way of control them in different preparation methods. New application in gas and humidity sensing is also mentioned. At the end, we briefly discuss the possible directions of VO2(B) materials in the future's research, hoping that this article can provide a valuable reference for research of VO2(B) in the future.

BACKGROUND: Epidemiological data regarding the regional differences in chronic pancreatitis (CP) from the mainland of China is lacking. We aimed to gather and combine the information concerning the regional distribution and the risk factors associated with pancreatic cancer (PaCa) and death from published articles. METHODSː:Case articles on CP published in seven databases from January 1979 to December 2018 were analysed. RESULTS: A total of 4,452 cases articles (containing 161,243 CP cases) were included. Since the mid-1990s, the number of published articles grew rapidly, which was significantly related to the gross domestic product of the region. In recent years, the number of CP cases of idiopathic etiology, those receiving endoscopic treatment, those with comorbid diabetes mellitus and the number of Science Citation Index (SCI) case articles have increased. Surgical treatment (37.4%) was closely associated to alcoholic CP (r = 0.55, P = 0.000), idiopathic CP (r = 0.52, P = 0.000), wasting (r = 0.21, P = 0.000), jaundice (r = 0.27, P = 0.000), PaCa and death detected during hospitalization and follow-up, and was more common in underdeveloped areas. Endoscopic therapy (27.9%) was mainly concentrated in developed areas, associated with non-alcoholic CP and a higher incidence of death (r = 0.48, P = 0.000) and PaCa (r = 0.3, P = 0.000) during follow-up. The total number of PaCa in CP cases was significantly related to the number of PaCa cases in each region (r = 0.94, P = 0.002). PaCa detected during hospitalization was mainly related to jaundice, pain, diabetes, biliary diseases, alcoholic CP, conservative treatment and surgical treatment. CONCLUSIONS: The distribution of clinical features and management treasures showed obvious regional characteristics, which closely related to the local detection level of CP and PaCa, showing that there were likely to be many cases of misdiagnosis or delayed diagnosis of CP and PaCa. The problem of uneven distribution of medical resources, which related to the imbalance of economic and social development, needs to be resolved.

Nonvolatile optoelectronic memory (NVOM) integrating the functions of optical sensing and long-term memory can efficiently process and store a large amount of visual scene information, which has become the core requirement of multiple intelligence scenarios. However, realizing NVOM with vis-infrared broadband response is still challenging. Herein, the room temperature vis-infrared broadband NVOM based on few-layer MoS

With the development of perovskite photodetectors, integrating photodetectors into array image sensors is the next target to pursue. The major obstacle to integrating perovskite photodiodes for dynamic imaging is the optoelectrical crosstalk among the pixels. Herein, a perovskite photodiode-blocking diode (PIN-BD) crossbar array with pixel-wise rectifying property by the vapor deposition method is presented. The PIN-BD shows a large rectification ratio of 3.3 × 10

Recently, the two-dimensional material Ti3C2Tx MXene has attracted interest from researchers in perovskite solar cells (PSCs) with its great advantages in terms of high transmittance, high conductivity, tunable work function, and solution processability. However, the MXene-based PSC performance has still been inferior to that of the traditional TiO2- or SnO2-based counterpart up until now. Some critical issues regarding to the MXene/perovskite interface still have not been well addressed. Herein, we used the Ti3C2Tx MXene as electron transport layer in PSCs via a room-temperature solution process followed by oxygen plasma treatment. Various characterization techniques were taken to establish the correlation between the surface properties and termination groups of MXene. We showed that oxygen plasma treatment could break parts of Ti-C bonds and generate abundant Ti-O bonds randomly distributed on MXene. The surface modification resulted in tunable work functions of MXene, as well as reduced trap states and improved electron transport close to the interface. In addition, the surface tension of MXene and corresponding perovskite morphology were thoroughly investigated by the contact angle and topography measurements. High-resolution XPS spectra indicated the Pb-O interactions between perovskite and MXene, which contributed to the device stability improvement.

Two-dimensional van der Waals crystals (2D vdW) are recognized as one of the potential materials to solve the physical limits caused by size scaling. Here, vdW metal oxide MoO

In this paper, we propose a new kind of multivariate t distribution by allowing different degrees of freedom for each univariate component. Compared with the classical multivariate t distribution, it is more flexible in the model specification that can be used to deal with the variant amounts of tail weights on marginals in multivariate data modeling. In particular, it could include components following the multivariate normal distribution, and it contains the product of independent t-distributions as a special case. Subsequently, it is extended to the regression model as the joint distribution of the error terms. Important distributional properties are explored and useful statistical methods are developed. The flexibility of the specified structure in better capturing the characteristic of data is exemplified by both simulation studies and real data analyses.

Distinct from CsSnI3 perovskite systems, the most stable non-centrosymmetric trigonal structure (space group of R3m) of the CsGeI3 perovskite system was found in our calculations. We systematically studied the differences between two all-inorganic perovskites (CsSnI3 and CsGeI3) and proposed an unexpected distorted stable structure of the mixed Sn–Ge perovskite system (CsSn0.5Ge0.5I3). All calculations of structural configuration and electronic properties were performed in the projector augmented-wave density-functional theory framework via the generalized gradient approximation (GGA). We found that the energy band evolutions of all-inorganic perovskites CsSnxGe1−xI3 are completely different from those of the Sn–Pb perovskite compounds. After considering the spin–orbit coupling (SOC) effect, the bandgap evolution of the stable structure shows a linear change. The results unravel the previous controversial understanding of the atomic and electronic properties of Ge-based perovskite solar cells.

Collecting water from fog flow has emerged as a promising strategy for the relief of water shortage problems. Herein, using a UV-induced (ultraviolet light induced) controllable diffusion method combined with technology of three-dimensional (3D) printing, we fabricate biomimetic materials incorporating beetle-like hydrophobic-hydrophilic character and cactus-like cone arrays with various structure parameters, and then systematically study their fog-harvesting performance. The UV-induced controllable diffusion method can break away from the photomask to regulate the hybrid wettability. Moreover, employing 3D printing technology can flexibly control the structure parameters to improve the water collection efficiency. It is found that the water collection rate (WCR) can be optimized by controlling the hybrid wettability of the sample surface and cone distance and using substrates with printed holes, which lead to a 109% increase of WCR.

Because of a lack of solvent-assisted crystallization, vapor and reaction process controls are essential for structural regulation in vapor-deposited organic–inorganic hybrid perovskite thin films....

In order to realize the broadband photodetection, Co–Sn co-doped layered α-MoO3 was observed experimentally to show the excellent optoelectronic and electrical properties. In this study, first-principles calculations and Raman spectroscopy were performed to unravel the inside mechanism of the diatomic co-doped α-MoO3 system. Intriguingly, the synergy of polaron and d-orbitals was found to play an important role in tuning the electronic properties of broadband α-MoO3. Due to the large ionic radius of the Sn atom, it mainly influences the electronic properties of the co-doped system through the polaron effects, which is shown in the obvious lattice distortion after doping. Considering the fact that the transition metal Co atom has a small ionic radius, it predominantly contributes to the extended gap states of α-MoO3 by its d orbitals. When Co and Sn elements were co-doped in the system, the synergy of the polaron and d-orbital shows remarkable effects on the optoelectronic properties, light absorption, and conductivity. Furthermore, the influence of the doped sites indicating the intercalated styles and the dopant concentration was systematically investigated in our calculations. Therefore, the present work provides a fundamental understanding of the Co–Sn co-doped α-MoO3 layered materials and offers strategies for designing a more superior photodetection device.

Herein, we propose a new approach of molecule occupancy via a vapor treatment to facilitate the conversion of PbI2 to perovskite in sequential deposition. We have shown that the morphology of PbI2 and the subsequent crystallization of perovskite can be effectively tuned, thus leading to the elimination of residual PbI2 and promotion of perovskite growth.

We theoretically investigated the structural and electronic properties of the all-inorganic perovskite CsSn1−xPbxBr3, compared with the mixed perovskite compound MAyCs1−ySn1−xPbxBr3, based on first-principle calculations. It has been demonstrated that Pb and Sn atoms are inclined to occupy the lattice sites uniformly in the all-inorganic perovskite, and this is distinguished from the most stable configurations observed in the mixed Cs-MA system. It is interesting that small Sn atoms prefer to stay close to the large MA+ cations, leading to smaller local structural distortion. Through spin-orbital coupling calculations, we found non-linear bowing band evolution in the all-inorganic mixed Sn–Pb system with a small bowing parameter (b = 0.35), while the band gap of MAyCs1−ySn1−xPbxBr3 was clearly reduced as the ratio of MA was around 0.5 (y ≥ 0.25). We determined the bowing band evolution in the mixed cation perovskites and the intrinsic electronic deficiency of the all-inorganic perovskite to obtain the optimal band gap.

Intercalation has proven to be a powerful strategy for physical and chemical property modulation in two dimensional (2D) van der Waals (vdW) materials. Traditional gaseous and chemical intercalation methods offer the ability for mass production, and the electrochemical method provides reversible fine tuning for in situ material investigation. Spatial control, or even direct patterning, of ions is widely required for practical device fabrication and integration; yet it is not realized. Here we demonstrate a self-driven ion (Co2+, Sn4+, and Cu2+) intercalation approach with patterning ability on vdW α-MoO3. It is proved that the self-driven intercalation was enabled by the formation of a local galvanic cell and could be controlled by the metal electrode potential and the solution concentration. The universality of self-intercalation was confirmed in various types of 2D materials (MoS2, WS2, MoSe2, WSe2 and graphene). Furthermore, the feasibility of building heterostructures by multiple species (Sn & Co) intercalation in a single nanosheet was demonstrated for broadband photodetection. The enhancement of conductivity and photoresponse was found to be due to the synergistic effect of lattice distortion from Sn intercalation and the d orbital from the Co atom. This approach offers a feasible way for direct nano-fabrication in 2D vdW material and functional device integration.

The preparation of a pure phase has long been the key obstacle for the fundamental research and device application of Wadsley vanadium oxides (VnO2n+1) due to the mixed-valence feature and closeness in thermodynamic phase diagrams. Herein, we demonstrate a melt-assisted pyrolysis process to prepare pure V6O13 (n = 6) using a V2O5 precursor film. V6O13 with an atomic flat (00l) terrace and length up to a millimeter was prepared on a c-cut sapphire surface. Both ex situ and in situ real-time investigations on the growth process reveal that the melting and decomposition of V2O5 started as synchronization processes for the nucleation of V6O13. The endothermic melting process provides the main driving force for the rapid growth of V6O13 crystals along the melt/solid interface. The as-prepared V6O13 crystal sheets show a broadband photoresponse capability (0.4–8.8 μm) with a rise/fall time of 42 ms/50 ms, and the maximum EQE of 5.4 × 104%. Spatial photocurrent imaging reveals that both photoelectric and bolometer effects contribute to the photoresponse. This study offers a feasible and scalable method for the preparation of high quality mix-valence vanadium oxide for future opto-electrical and energy storage devices.

Two-dimensional (2D) hybrid perovskites have been extensively studied as the promising light-sensitive materials in the photodetectors owing to their improved structural stability over that of their three-dimensional counterparts. However, the application of the 2D perovskite-based photodetector in the near-infrared (NIR) region is obstructed by the large intrinsic optical band gap. Herein, we develop a novel van der Waals heterostructure composed of few-layer 2D perovskite/MoS

Van der Waals (vdW) integration of two-dimensional (2D) nanosheets provides the possibility to design optoelectronic devices with extended functionality in a controllable manner. Here, by leveraging the appropriate energy band alignment and the high-efficiency charge transfer at the junction, we construct the MoS2/graphene/2D-perovskite vdW heterostructure, which realizes the highly sensitive and broadband photodetection. Particularly, at the near-infrared (NIR) wavelength (λ = 1550 nm), the heterostructure photodetector shows a balanced trade-off between the high responsivity (>3000 A/W) and fast response time (

Schottky-contacted nanosensors have attracted extensive attention due to their high sensitivity and fast response time. In this article, we proved that the construction of Schottky contact by Pt nanoparticles (NPs) decoration can effectively improve the performance of V

Recently, the two-dimensional material Ti

A two-dimensional (2D)/three-dimensional (3D) hybrid heterostructure has recently emerged as an effective method for improving photocatalytic efficiency. In this work, we perform a comprehensive first-principles study of the structural, electronic, and optical properties of a novel 3D-SiC/2D-MoS2 heterostructure. The calculation results reveal that the SiC(0001) surface/MoS2 monolayer-integrated heterostructure in Schottky contact with a new chemical bonding contributed to the surface adhesion and optoelectronic properties. Meanwhile, the valence and conduction band-edge positions of SiC and MoS2 changed with the Fermi level and formed a desired type-II band alignment, which greatly facilitate the rapid separation of photogenerated carriers. Moreover, the surface state of SiC(0001) can be removed when combined with MoS2, and their band gap is also reduced. Furthermore, Bader charge and charge density difference indicated that there is a remarkable separated distribution of electrons and holes at the inter...

The device stability and toxic-solvent-free processing are indispensable development to industrialize organometal halide perovskite solar cells. In this work, the conventional top surface of vapor prepared 3D-MAPbI3 was replaced by 2D-(BA)2(MA)n‐1PbnI3n+1 perovskite platelet via molecular substitution from MA (CH3NH) to BA (C4H9NH2). Our fully vapor process fabricated a 3D-2D perovskite heterojunction for solar cell application, realizing the power conversion efficiency as high as 16.50% and the average one as 15.40%. Furthermore, unencapsulated devices can sustain their 81% efficiency after 30 days under 55% RH, and also 74% efficiency after 30 days under 80 °C heat stress. Stability of humidity resistance arises from the reduced n value of 2D perovskite caused by the surface reaction of moisture, and the improvement of thermal stability comes from the buffering of MA molecules release. Meanwhile, the fabrication of large scale device with high efficiency is also demonstrated in our experiment.

In this work, the structural, optoelectronic, and defect properties of both the α-phase and β-phase CsPbI2Br are investigated based on first-principles calculations. First, we calculate the bandgap of α-CsPbI2Br using the standard HSE06 method which is in accordance with the experimental bandgap value of 1.9 eV. We also find that α-CsPbI2Br shows comparable optoelectronic properties to CsPbI3. More intriguingly, our calculated results show that both α-phase and β-phase CsPbI2Br possess better thermal and phase stability than CsPbI3 due to the mixture of halide elements, and the optical absorption coefficient of CsPbI2Br also resembles that of CsPbI3 and MAPbI3 due to the lone pair electrons of Pb. Furthermore, the formation energies and transition energy levels of intrinsic point defects indicate that CsPbI2Br exhibits unipolar self-doping behavior (p-type conductivity) and similarly good defect tolerance while the dominant defect changes. Therefore, our present work provides fundamental understanding of the great performance of CsPbI2Br thin films and offers strategies for designing more superior CsPbI2Br-based devices.

Vapor reaction is one of the major methods used for large-scale fabrication of high-quality organic–inorganic halide perovskite solar cells, but its detailed process is rarely investigated. In this study, the thermal and illumination effects on PbI2 and its transformation to CH3NH3PbI3 (MAPbI3) under CH3NH3I (MAI) vapor were investigated. Atomic shifting of the PbI2 layer was observed, which caused the generation of defects and distortion in PbI2 without breaking the phase structure. The reaction with MAI started with decoupling of PbI2 layers and formation of nanoislands and then, the transformation of PbI2 to MAPbI3 proceeded randomly on the surface from top to bottom. Additional illumination of the reaction suppressed the transformation, causing the generation of PbI2 nano-walls along [100] and [010] directions, leading to decrease in power conversion efficiency.

Vacancy defects are universally regarded to be the main defect that limits the photoelectric conversion efficiency of perovskite solar cells. In perovskite, iodine vacancy dominates the defect proportion due to its low formation energy. However, the defect property of iodine vacancy (VI) is still in dispute. Ideally, the VI defect is considered to be a shallow level defect near conduction band minimum, meaning that it does not act as a Shockley–Read–Hall (SRH) nonradiative recombination center. Herein, we find a direct correlation between compressive strain and VI defect behavior. The compressive strain along the lattice vector b/c direction will drive the VI defect from shallow level to deep level defect, which is related to the formation of Pb-dimer. In addition, the influence of extra electrons is also considered during the structural evolution of VI, which is often observed in the experiments. Therefore, we find that the elimination of compressive strain and extra electrons can be of great significance for improving the photoelectric performance of perovskite solar cells. Our work reveals the defect properties of VI from shallow level one to the SRH recombination center and the inherent physics mechanism of defect evolution under external factors, which provides a strategy to control device defects and eliminate recombination losses.

At present, perovskite solar cells have achieved a conversion efficiency that can be comparable to conventional silicon solar cells, but the stability of perovskite is still difficult to make great breakthroughs. And the mechanism of the intrinsic instability and the instability caused by the external environment of the perovskite are not yet clear. Although XPS (X-ray photoelectron spectroscopy) and UPS (ultraviolet photoelectron spectroscopy) are two widely used methods in perovskite investigation, the instability phenomenon of perovskite film during the XPS and UPS measurement has not been taken seriously. This work aims to illustrate the effects of thermal annealing and illumination of ultraviolet light and X-rays on the composition and energy level structure of perovskite films. It was found that the composition and the work function of perovskite film are highly sensitive to annealing temperature while the valence band maximum (VBM) remains basically unchanged. And the perovskite CH3NH3PbI3 film tends to degrade into different products under X-ray and ultraviolet light. The intrinsic degradation process in vacuum is: the CH3NH3I molecules leave surface with increasing temperature.

Summary The expensive and unstable organic hole transport layer (HTL) is one of the crucial problems that hampers the wide application of perovskite solar cells. Here, an MAPbI3-(BA)2(MA)n−1PbnI3n+1 3D-2D perovskite-perovskite planar heterojunction (PPPH) through a facile BAI and MAPbI3 interfacial ion exchange process was conducted. A graded band structure was formed for efficient charge separation, and the conductivity of the 2D perovskite can be tuned by extrinsic FA incorporation, which provides effective conducting channels for holes, making the modified 2D perovskite layer a promising and stable HTL. Optimized solar cells based on 3D-2D PPPH showed a champion power conversion efficiency (PCE) of 13.15% initially and 16.13% after thermal aging, and could maintain 71% output for 50 days under 65% humidity, and 74% for 30 days under 85°C, without encapsulation. This work points to realize low cost and ambient compatible PPPH solar cells with high PCE and robust stability.

Long-term stability of organic-inorganic hybrid perovskite solar cells (PSCs) is inhibited by ion diffusion. Herein, we introduce a thermally stable and hydrophobic silicone resin layer with a network structure as an interfacial layer between the perovskite and the hole-transporting layer (HTL). Experimental and theoretical investigations confirm that the small Si-O-Si unit in the network forms both Si-I and Pb-O bonds with the perovskite surface, which physically and chemically inhibit the diffusion and self-release of iodine. Besides, the silicone resin layer suppresses the thermal crystallization of spiro-OMeTAD and optimizes the interfacial energy level alignment for hole extraction. The power conversion efficiency (PCE) of a perovskite solar cell with a silicone resin layer is improved to 21.11%. The device maintains more than 90.1% of its original PCE after 1200 h under 85 °C thermal stress, 99.6% after 2000 h under RH ∼55 ± 5%, and 83% of its original PCE after light soaking in air for 1037 h.