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CsPbIxBry-based all-inorganic perovskite materials are a potential candidate for stable semitransparent and tandem structured photovoltaic devices. However, poor film (morphological and crystalline...

Organic-inorganic hybrid perovskite solar cells (PSCs) are promising next-generation photovoltaic technology. However, their long-term operation is limited due to thermodynamic instability of hybrid perovskites (loss of organics) and severe migration of constituents (ions and dopants). PSCs have to be free of volatile organics and mobile dopants to become commercially relevant. PSCs based on cesium lead halide inorganic perovskites (CsPbI3−xBrx, x = 0 ~ 3) and a carbon electrode, abbreviated here as C-IPSCs, fulfill these requirements: CsPbI3−xBrx is stable against decomposition to binary halides and the carbon electrode is inherently moisture-resistive and dopant-free. Since the first report of C-IPSCs in 2016, their power conversion efficiencies (PCEs) have doubled, recently reaching 14.84% with an astonishing stability of over 2000 h at 80 °C and 80% relative humidity (RH). Here we review recent progress of C-IPSCs and analyze the remaining critical issues in the field. We then offer our perspective to address these challenges through morphology, interface, spectral and material engineering. Finally, we argue that C-IPSCs have potential to overcome the 20% efficiency milestone, making them – in combination with their already impressive stability – the most promising PSC architecture for commercialization.

Up to date, solid-state carbon dots (CDs) with bright red fluorescence have scarcely achieved due to aggregation-caused quenching (ACQ) effect and extremely low quantum yield in deep-red to near infrared region. Here, we report a novel fluorine-defects induced solid-state red fluorescence (λem = 676 nm, the absolute fluorescence quantum yields is 4.17%) in fluorine, nitrogen and sulfur co-doped CDs (F,N,S-CDs), which is the first report of such a long wavelength emission of solid-state CDs. As a control, CDs without fluorine-doping (N,S-CDs) show no fluorescence in solid-state, and the fluorescence quantum yield/emission wavelength of N,S-CDs in solution-state are also lower/shorter than that of F,N,S-CDs, which is mainly due to the F-induced defect traps on the surface/edge of F,N,S-CDs. Moreover, the solid-state F,N,S-CDs exhibit an interesting temperature-sensitive behavior in the range of 80–420 K, with the maximum fluorescence intensity at 120 K, unveiling its potential as the temperature-dependent fluorescent sensor and the solid-state light-emitting device adapted to multiple temperatures.

Metal phosphates have shown good hydrogen evolution reaction catalytic ability, but as counter electrode (CE) materials they are rarely used in dye-sensitized solar cell (DSSC). A strategy that introduction of Co2P2O7 as a “collaborator” to improve the catalytic performance of Co4S3 for the DSSC. The Co4S3/Co2P2O7 film grew on carbon paper (CP) was synthesized by using a hydrothermal route and vapor deposition method, and served as platinum-free (Pt-free) CE for DSSC. The composite materials of Co4S3/Co2P2O7 has many advantages of unique spherical morphology, large special surface area, more active sites and fast reaction kinetics for the reduction of I−/I3−. Under optimal conditions, a DSSC based on the Co4S3/Co2P2O7/CP CE achieves a high power conversion efficiency of 8.99%, which is comparable to that of the Pt (7.49%) and CoS1.097/CP (8.18%) CEs. The results indicate that the Co4S3/Co2P2O7/CP CE with the advantages of efficient and facile synthesis is a promising alternative to the expensive Pt CE for the DSSCs in the future.

The over exploitation of stone quarries, the generation of construction and demolition (C&D) waste, and the steady increase in the cost of preparing additional landfill space have caused great challenges to the environment and economy. Recycled aggregate concrete (RAC), as one of the sustainable construction material, has become a research hotspot and has received widespread attention. However, the formation of weak interface transition zone (ITZ) which caused by the existence of residual old mortar will exert a negative impact on the performance of RAC. Therefore, various treatments have been proposed to enhance the properties of the residual old mortar, including mechanical treatment, soaking, carbonation and so on. And it has been proved that carbonation is an effective and sustainable way to both improve the water absorption of RA and strengthen the ITZ of RAC. So, firstly, this article is devoted to reviewing the current research on the application of carbonized RA to RAC, focusing on two parts: (1) RA: the changes of physical properties under different conditions; (2) RAC: the microstructure, workability, mechanical properties and durability of the concrete with carbonized RA. Thereafter, it is known from the summarized literatures that carbonation can improve physical properties of RA and the optimal effect can be achieved by adjusting carbonation conditions. RAC with carbonized RA has denser both new and old ITZs, the microstructure, performance of it are also improved. Finally, this work may provide a reference for the research of carbonation and the application of RA in engineering in the future.

Designing efficient and economical dye-sensitized solar cells (DSSCs) free of precious metals is required to replace the platinum counter electrode (Pt CE) for further large-scale development. Here...

A uniform diffusion layer is essential for non-dendritic deposition of lithium in high-density lithium batteries. However, natural pristine solid electrolyte interface (SEI) is always porous and inhomogeneous because of repeated breakdown and repair cycles, whereas ideal materials with excellent mechanical property for artificial SEIs remain a challenge. Herein, a robust and stable interface is achieved by spinning soft polymer associated with few MoO3 into fibers, and thus mechanical property of fibers other than materials determines mechanical performance of the interface which can be optimized by adjusting parameters. Furthermore, lithium deposited underneath the layer is enabled by constructing an optimal resistance to make the membrane serve as an artificial SEI rather than lithium host. As a result, dendrite-free lithium was observed underneath the membrane, and stable interface for long-term cycling was also indicated by EIS measurements. The lithium iron phosphate (LiFePO4) full-cell with coated electrode demonstrated an initial capacity of 155.2 mAh g−1, and 80% of its original capacity was retained after 500 cycles at 2.0 °C without any additive in carbonate-based electrolyte.

Defect passivation management of perovskite films is of great importance in improving the performance of perovskite solar cells. Various in situ or post-passivation strategies were adopted to modify the optoelectric properties of perovskite films. However, these modifications increased the fabrication complexity and cost of the devices. Here, we developed a facile self-passivation strategy to effectively decrease charge trap states and suppress the non-radiative recombination loss in perovskite films. By simply aging the precursor solution, we found that the fabricated perovskite films possess residual PbI2 phase that could decrease trap density, enhance the radiative recombination intensity, and facilitate charge transfer and collection. Therefore, the solar cells with this self-passivated perovskite film generated an increased efficiency of 21.1% compared to that of 19.9% for the control devices from fresh precursor solution.

Transition metal oxychlorides (TMOCl) have attracted great attention as promising cathode materials for chloride ion batteries (CIBs). However, current research on TMOCl has been mainly focused on FeOCl and VOCl. On the other hand, the theoretical study of anionic rechargeable batteries faces the difficulty of predicting the discharge voltage of the electrode materials based on the half-cell system. Herein, a reliable theoretical voltage formula for CIBs is proposed based on a full-cell system with Li/LiCl as the reference anode. A high throughput screening method for TMOCl is applied among 16 transition metals. After the screening according to energetic and dynamic stability, Co is identified, which can form a new cathode material of CoOCl. Compared to FeOCl and VOCl, CoOCl has a higher discharge voltage, which is beneficial for achieving a larger energy density. The small crystal field splitting energy and exchange splitting energy of Co3+ result in higher electronic conductivity. In addition, the uniform Cl− binding environment leads to a low Cl− diffusion barrier of 0.37 eV, which is much smaller than that of VOCl (0.65 eV) and FeOCl (0.58 eV).

Lead-free metal halide perovskites have attracted extensive attention as promising optoelectronic semiconductors with environmental friendliness. Cs2SnI6, a double perovskite with both a good phase and composition stability, is an appealing candidate for potential application in optoelectronic devices. To date, few reports have focused on the facile fabrication of dense and uniform Cs2SnI6 films that are key components for optoelectronic devices. Herein, a simple and low-cost solution method is reported to prepare densely packed Cs2SnI6 thin films. It was found that strategic precursor-compensation treatment (PCT) of the as-prepared spin-coated Cs2SnI6 thin films compensates the evaporation loss of volatile SnI4 and thus allows for pinhole-free and pure-phase double perovskite. The modified n-type Cs2SnI6 double perovskite shows enhanced conductivity and mobility with decreased charge recombination loss. As a result, the applied photodetectors show an enhanced photocurrent gain of 151 compared to that of 88 for the control sample. The responsivity (control 0.0059 mA W−1 to target 1.07 mA W−1) and detectivity (control 2.94 × 1010 Jones to target 6.03 × 1010 Jones) of the device were significantly improved in the self-powered mode. In addition, the PCT-Cs2SnI6 photodetectors show excellent long-time stability with 98% initial detectivity retained after storing in ambient environment for 28 days. This study paves the way for the preparation of high-quality Cs2SnI6 films for application in efficient optoelectronic devices.

Sensitivity is one of the greatest concerns in explosive materials, and its underlying mechanism remains ambiguous. In this study, 2,6-diamino-3,5- dinitropyrazine -1-oxide (LLM-105) crystals with different morphologies, such as crosswise, needle, plate, block, diamond, and spherical shapes, were prepared using a solution crystallization method, and their crystal characteristics and sensitivity were investigated. It was found that the H50 values (impact sensitivity) of LLM-105 vary within an extremely wide range of 33.8–112.2 cm and are mainly influenced by the particle morphology, crystal integrity, particle surface defects, and roughness, but are mostly independent of intracrystalline defects and particle sizes. The friction sensitivities of all samples are zero and are unaffected by the crystal characteristics. The G50 values (shock sensitivity) are within the range of 0–6.9 mm, increasing with decreasing particle sizes and the apparent crystal density. Notably, LLM-105 crystals with a spherical shape, good integrity, smooth surface, and fewer defects are insensitive to impact and shock impulse. The relationships between the crystal characteristics and the sensitivity of LLM-105 are extremely complex and show some abnormal phenomena, which can be attributed to the crystal packing style and aggregated microstructures of LLM-105.

A technological method of pulse laser assisted plasma transferred arc (Laser-PTA) additive manufacturing was proposed. The characteristics of microstructure such as austenite morphology, grain size and grain orientation were investigated through Scanning Electron Microscope (SEM) and Electron Backscattered Diffraction (EBSD) test. In particular, the mechanisms of pulsed laser affecting the molten pool and regulating the microstructure were revealed by the analysis on the temperature and dynamic response of molten pool. The experimental results show that an appropriate intensity of pulsed laser promotes the distribution uniformity of austenite, grain refinement and porosity reduction. The microstructure is transformed from lath-shaped austenite into skeleton-shaped austenite in deposition layer manufactured by Laser-PTA additive manufacturing. Furthermore, distribution of grain orientations in deposition layer became more random compared with those manufactured by PTA additive manufacturing. Under the excitation of pulsed laser, the molten pool oscillates in the boiling phase and oscillating phase, which strengthens the molten fluid flow. The enhanced fluid flow could reduce the temperature gradient and change the direction of the maximum temperature gradient, furthermore break the dendrites to form new heterogeneous nucleation particles. Therefore, the main factor causing the microstructure change is the oscillation of molten pool induced by pulsed laser.

Carbonized polymer dots (CPDs) are promising fluorescent probes for bioimaging, biomarkers, sensors, etc. Here a type of thermosensitive CPD (ts-CPD) was synthesized via a solvothermal method from ...

Carbon dots (CDs) are relatively new and one of the most propitious nanomaterials ever known to humanity, primarily consisting of a carbonized carbon core with heteroatoms in organic functional groups attached. CDs show various fascinating properties, such as tunable excitation/emission, chemical inertness, photostability, low toxicity, good biocompatibility, ease of handling, and eco-friendliness. Due to the anomalous optical and chemical properties of the CDs, they have a wide range of applications in the fields of bioimaging, biosensing, photocatalysis, optoelectronics, etc. In this Review, we intend to cover the many strides in CDs chemistry, which is an emerging paradigm, in conjunction with the most recent discoveries of CDs with near-infrared fluorescence, phosphorescence, electroluminescence, chirality, and antibacterial activity. Our main emphasis will be on the contemporary evolution in synthetic strategies, optical properties, and biomedical applications of CDs in nanomedicine and nanotheranostics.

The iron species in the lower valence state in steel slag are capable of thermochemical H2O splitting and producing hydrogen energy. The defining of the slag reactivity with varying particle size distributions was put forward. The results showed the hydrogen generation rate was primarily dependent on temperature and particle size. The kinetics analysis revealed a typical self-retardation reaction behavior for the fine slag, due to the clogging of macropores upon oxidation. In comparison, the reaction kinetics of the coarser slag were described well by three-dimension diffusion model and exhibited better resistance against the rate decline. The coarser slag had much more grain junctions and fewer fraction of RO phases distributed at the particle surface. Due to the lack of free surfaces, the volume expansion derived from the oxidation of RO phase would cause larger mismatch stresses at grain boundaries, and further trigger the cracks formation.

Enzymes have been widely used because of their catalytic properties, and immobilization is a promising technique to improve their catalytic activity and stability. Due to their large specific surface areas, exceptional chemical, mechanical, thermal and cost effective characteristics, nanomaterials should be ideal carriers for the immobilization of enzymes. Enzymes immobilized on nano-carriers are more robust and stable, and can be recycled and reused. This review focuses on the nanomaterial immobilized enzymes and their applications. The introduction addresses the advantages of immobilized enzymes and the features of enzyme immobilization nanocarriers. The next section covers carbonaceous nanomaterials used in enzymes immobilization, with subsections on carbon nanotube, graphene, graphene oxide and reduced graphene oxide. The third section treats metallic nanomaterials for enzymes immobilization, with subsections on metal (gold), metal oxide (titanium dioxide, zinc oxide) and metal hydroxide (layered double hydroxide) nanomaterials. Then, the next section summarizes the applications of nanomaterial immobilized enzymes. A concluding section discusses the challenges and prospects of nanomaterial immobilized enzymes.

The hot compression behavior of the nickel-based heat-resistant alloy C-HRA-2® was investigated by a Gleeble-1500 thermo-mechanical simulator with the deformation temperature range of 950–1150 °C and the strain rate of 0.001–10 s−1. The constitutive equation of the alloy was established by using a hyperbolic sine function, and the peak stress followed a power law relationship with the Zener–Hollomon parameter (Z). The activation energy was about 446 kJ mol−1 for the whole hot deformation domain in this alloy. The optimum hot deformation condition was obtained in the temperature range of 1050–1150 °C and the strain rate range of 0.005–0.1 s−1. Unsafe domains during the hot deformation would occur in the strain rate range of 0.1–10 s−1 with inhomogeneous microstructure and high-density twins in the alloy. The dominant nucleation mechanism of dynamic recrystallization (DRX) was continuous dynamic recrystallization with sub-grain rotation at high strain rate, while DRX at low strain rate was discontinuous dynamic recrystallization with original grain boundaries bulging.

Lithium metal anode is a promising electrode with high theoretical specific capacity and low electrode potential. However, its unstable interface and low Coulombic efficiency, resulting from the dendritic growth of lithium, limits its commercial application. PIM-1 (PIM: polymer of intrinsic microporosity), which is a polymer with abundant micropores, exhibits high rigidity and flexibility with contorted spiro-centers in the backbone, and is an ideal candidate for artificial solid electrolyte interphases (SEI). In this work, a PIM-1 membrane was synthesized and fabricated as a protective membrane on the surface of an electrode to facilitate the uniform flux of Li ions and act as a stable interface for the lithium plating/stripping process. Nodule-like lithium with rounded edges was observed under the PIM-1 membrane. The Li@PIM-1 electrode delivered a high average Coulombic efficiency (99.7%), excellent cyclability (80% capacity retention rate after 600 cycles at 1 C), and superior rate capability (125.3 mAh g −1 at 10 C). Electrochemical impedance spectrum (EIS) showed that the PIM-1 membrane could lower the diffusion rate of Li + significantly and change the rate-determining step from charge transfer to Li + diffusion. Thus, the PIM-1 membrane is proven to act as an artificial SEI to facilitate uniform and stable deposition of lithium, in favor of obtaining a compact and dense Li-plating pattern. This work extends the application of PIMs in the field of lithium batteries and provides ideas for the construction of artificial SEI.

Lithium metal has been considered to be the most promising anode material for the new generation of energy-storage system. However, challenges still stand in protecting lithium metal from spontaneous reactions with electrolytes and preventing the dendritic propagation, both of which would lead to undesirable decrease in Coulombic efficiency. Polysulfone (PSf) membrane with high rigidity and free-volume cavities of approximately 0.3 nm was employed to provide a stable interface on the surface of anodic electrode. The isotropic channels were constructed by the interconnected and uniformly distributed free volumes in the polymer matrix, and were expected to be swelled by solvent molecules and anions of lithium salt and to allow Li+ ions to pass through onto the electrode surface. As a result, dendrite-free morphology of deposited lithium was observed. The stabilized interface arose from the PSf film was verified by the promoted performances of Cu|Li cells and steady voltage polarization of Li|Li cells. The full cell with PSf coated anode exhibited excellent cyclability (85% capacity retention rate over 400 cycles at 1 C) and an outstanding rate capability (117 mAh g−1 at 5 C). The beneficial performances were further verified by the EIS results. This work provides a new strategic idea to settle the dendritic problems of Li metal anodes.

薄膜晶体管液晶显示器（TFT-LCD）扭曲向列型（TN）液晶曲面显示器搭配宽视角偏光片暗态时会发生色不均现象，推测色不均现象的发生机理为：曲面状态时，玻璃基板受应力发生形变，面板中应力不均，加之液晶双折射，暗态时上视角观察显示屏上下两侧边缘发蓝。本文模拟了不同改善措施对色不均现象的影响，同时对有改善的模拟结果进行了实验测试。测试结果表明，可以通过两种方式改善色不均现象：第一种是增加暗态亮度，掩盖暗态时色不均现象，如调整电路、偏光片吸收轴角度等。实验结果表明调整电路使显示器暗态亮度从0.18 cd/m2提升至0.25 cd/m2，色不均面积由显示器面积的30%减小至10%，吸收轴角度从135°调整至134.5°，色不均面积减小至10%，但电路调整使显示器响应时间增加2.5倍，吸收轴角度调整0.5°会使对比度下降20%，对产品性能均有不利影响；第二种是改善曲面状态下显示屏内部应力均一性，如增加液晶盒盒厚、高温老化、降低显示器玻璃基板厚度等。实验结果表明：降低玻璃厚度至0.2 mm以及高温60℃老化72 h均能使色不均现象消失，且对产品性能无不利影响。

The crystal structures and stability of energetic compounds are closely related to the energy, safety and reliability of weapons. Searching for new solid forms of an energetic compound has become an integral part of its development. The studied compound, carbonic dihydrazidinium bis[3-(5-nitroimino-1,2,4-triazolate)] (CBNT), is a recently synthesized high energy and low sensitivity energetic ionic salt with promising applications. Herein, we have investigated the crystal structure evolution and searched for new solid forms of CBNT under different conditions via the solvent induction method. The phase composition of all screened samples was analysed by powder or single-crystal X-ray diffraction. Four new solid forms of CBNT·2H2O (1), H2BNT·2DMSO (2), H2BNT·2H2O (3) and [NH2(CH3)2+]2[BNT2−]·2H2O (4) (BNT2− = bis[3-(5-nitroimino-1,2,4-triazolate)2−]) were obtained from water, DMSO, BL/H2O and DMF/H2O, respectively. Their molecular interactions were analysed by theoretical simulations of the Hirshfeld surface and molecular electrostatic potentials. Furthermore, the energetic properties have been verified through EXPLO5.

Background: Few studies have assessed the survival of restorations and particularly zirconia based crowns in the restoration of the severely worn dentition. This study aimed to determine survival and factors associated with failure in anterior teeth worn through to dentine restored with Lava™ crowns. Methods: A convenience sample of 30 participants (27 male, 3 female) had 161 Lava™ crowns placed by one specialist clinician in a hospital setting. Follow-up was over a median 72 month period. Results: Of the 161 Lava™ crowns only 25 failed (15.5%) in 15 individuals up to 84 months for the longest case. Major failures were total debond (N=7) or minor delamination chips within the veneer ceramic layer (N=18). The mean time to first failure was 25.23 months. The Kaplan Meier survival plot estimated the Mean Survival Time for the crowns to be 74 months (95%CI 70.4, 77.3). Failures by subject were not associated with an increase in Occlusal Vertical Dimension using a Dahl approach but were associated with an edge-to-edge incisal relation (p

In order to study the effect of water and CH4 concentration on gas explosion, a 20L spherical explosive device was used to carry out a water-containing gas explosion experiment, and the explosion simulation was carried out with CHEMKIN-PRO, the mechanism of water on gas explosion was analyzed from the perspective of free radicals and energy. The results showed that the upper limit of gas explosion, maximum explosion pressure and temperature decreased significantly with the increase of water content. The higher the concentration of CH4, the more obvious the inhibitory effect of water on gas explosion pressure, and the optimal explosion concentration of CH4 decreased with the increase of water content. As the water content and CH4 concentration increase, the residual CH4 content increases after the explosion, the O2 content decreases, and the CO content produced increases. When the CH4 concentration is lower than the optimal concentration, water promotes the formation of CO2 to a certain extent; when the CH4 concentration is higher than the optimal explosive concentration, the CO2 content decreases with the increase of water content. Overall, water inhibits methane explosion, the addition of water on the one hand reduces the concentration of active free radicals H, O, OH, on the other hand, it interferes with the generation of gas explosion energy and consumes the kinetic energy of the gas explosion flame shock wave through heat absorption, thus inhibiting the intensity of gas explosion.

Terahertz (THz) detecting technology has attracted many attentions. In this work, a novel THz detector based on a metal gratings/Si-based blocked-impurity-band (BIB) hybrid structure was designed and theoretically calculated. The highly integrated hybrid structure was found useful for modulating the response wavelength and improving the responsivity of Si-based BIB detector. The enhanced THz absorption of the hybrid device structure of metal gratings and Si-based BIB absorption layer was carefully investigated by finite difference time domain. The peak wavelength can be moved from 26.9 to 36.53 μm when metal gratings (period: 32 μm) were added on the Si-based BIB. The peak absorptivity of the hybrid detector was increased by 87.3 % with the metal gratings, compared with that of conventional Si-based BIB detector. Our results indicate that a highly integrated hybrid device structure can replace the divided band filters, and realize selective resonant enhanced absorption and tunable THz spectral response.

Long-lasting moisture retention is a huge challenge to humectants, and effective methods or additives for promote these functions are limited, especially nano-additives. Carbon dots (CDs) have attracted increasing research interest due to its ultra-small size, excellent optical properties and low toxicity, etc. However, most of researches have been focused on the photoexcited CDs and its subsequent photophysical and chemical processes, such as photoluminescence, photodynamic, photothermal and photocatalytic behavior. The intrinsic chemo-physical properties of the pristine CDs are not fully explored. Here, we report an excellent moisture retention capability of a new carmine cochineal-derived CDs (Car-CDs) for the first time. The relationship between the structure of Car-CDs and its moisture retention capability is revealed. More interestingly, the effective applications of Car-CDs in moisturizing lipstick are demonstrated. This work expands the research and application of CDs into a broad, new area, potentially in skin care. Supplementary Information The online version contains supplementary material available at 10.1186/s12951-021-01029-6.

This article proposes a cryogenic readout integrated circuit (ROIC) for the blocked-impurity-band (BIB) Terahertz detector. The cryogenic ROIC is composed of a capacitance transimpedance amplifier (CTIA) input-stage circuit, a correlated double sampling (CDS) circuit and an output-stage circuit. The circuit design is based on a cryogenic MOSFET model obtained by optimizing some parameters of BSIM4 according to previous cryogenic test results. The ROIC and BIB detector are interconnected by wire bonding, and the output characteristics are measured at 6K. Our result shows that the circuit has realized the design function under cryogenic conditions.

Transparent conductive coating (TCO) used as front contact layer in MoO x /n-Si heterojunction solar cells should feature excellent electrical properties, low optical absorption and high work function simultaneously. In this study, tin-doped indium oxide (ITO), titanium-doped indium oxide (ITiO) and zinc-doped indium oxide (IZO) deposited as front contact layer at room temperature by sputtering were evaluated. The open-circuit voltage is hardly affected by the work function of TCO film. The IZO front contact with Wf=5.22 eV enables to highest V oc of 606 mV. Meanwhile, high mobility and transmittance also boost the short-circuit current density to 33.04 mA/cm2. A cell efficiency of 12.2% has been achieved by applying IZO front contact and has high potential to obtain better electrical properties by introducing back surface field structure.

For the sake of direct using on the built wooden buildings, a green flame resistance coating comprising sodium polysilicate (SPS) and boric acid was prepared. With weight gain of only 10 wt.%, the treated wood sample (SPS/B-wood) performed improved limiting oxygen index value of 40.3% and passed the V-0 rating in UL-94 test. Additionally, the total heat release, total smoke production and peak carbon monoxide production of SPS/B-wood sample were decreased by 24.5%, 36.0% and 59.4% respectively, compared with that of control wood sample. The residue of SPS/B-wood sample was increased to 54.0% from 18.4% of control wood sample at 800oC in the thermogravimetry analysis. The flame retardant mechanism was suggested that SPS and boric acid formed Si-O-B and Si-O-Si contained structures, isolating the heat and smoke transfer during wood combustion. Notably, NaOH, introduced by the SPS/B coating, catalyzed the lignin to form compact and high-quality char. To conclude, this low-cost and easily-operated coating has a promising future utilizing in the villages with dense wood buildings.

Two-dimensional transition metal dichalcogenides (TMDCs) are promising in spintronics due to their spin–orbit coupling, but their intrinsic non-magnetic properties limit their further development. Here, we focus on the energy landscapes of TMDC (MX2, M = Mo, W and X = S, Se, Te) monolayers by rhenium (Re) substitution doping under axial strains, which controllably drive 1H ↔ 1Td structural transformations. For both 1H and 1Td phases without strain, Re-doped TMDCs have an n-type character and are non-magnetic, but the tensile strain could effectively induce and modulate the magnetism. Specifically, 1H-Re0.5Mo0.5S2 gets a maximum magnetic moment of 0.69 μB at a 6% uniaxial tensile strain along the armchair direction; along the zigzag direction it exhibits a significant magnetic moment (0.49 μB) at a 2.04% uniaxial tensile strain but then exhibits no magnetism in the range of [5.10%, 7.14%]. By contrast, for 1Td-Re0.5Mo0.5S2 a critical uniaxial tensile strain along the zigzag direction reaches up to ∼9.18%, and a smaller uniaxial tensile strain (∼5.10%) along the zigzag direction is needed to induce the magnetism in 1Td-Re0.5M0.5Te2. The results reveal that the magnetism of Re-doped TMDCs could be effectively induced and modulated by the tensile strain, suggesting that strain engineering could have significant applications in doped TMDCs.

Cu2SnS3 (CTS) based thin film solar cells were successfully fabricated through a facile solution processes followed by a post-sulfurization treatment. The influence of sulfurization temperature and time on the structural, compositional, morphological, optical and also the electrical properties of the solar cells were systematically studied. The results showed that the CTS thin films sulfurized at 580 °C would be a void-free and densely packed absorber layer with the grain size to be microns, having the band gap of ~ 1.01 eV. Furthermore, the sulfurization time is the key factor to influence the electronic properties of CTS absorber layer, and thus resulting in the best device performance of PCE = 2.41% by 20 min sulfurization process.

The microstructure, hardness, and residual stress of 0.28C–0.22Ti wear-resistant steel produced with cooling rates varying from 80.0 to 0.3 °C/s were determined using a dilatometer, scanning electron microscope, Vickers hardness tester, and nanoindentation tester. The results showed that the hardness of martensite decreased at a rate of approximately 0.935 HV/s with carbon diffusion time (the cooldown time required to transition from Ar3, 635–100 °C). The range of the residual stress caused by the hard particles decreased with decreasing cooling rate, from − 400–300 MPa (cooling rate 40 °C/s) to − 200–100 MPa (cooling rate 0.5 °C/s), proving that the TiC particles significantly contributed to the residual stress in the high-titanium steels.

Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) shows great promise in thin film photovoltaic application due to its reasonable band gap, low cost and non-toxic earth-abundant composition. Post-selenization is the generally adopted approach to obtain CZTSSe film with large-grain size. Thoroughly understanding and well controlling the grain growth process during selenization is thus essential for achieving high-performance solar cell devices. Here we demonstrate that the absorber microstructure can be adjusted by altering selenization conditions, especially the heating rate and annealing time. It is found that heating rate determines formation manner of top CZTSSe layer, while annealing time affects both the crystallization degree of bottom CZTSSe layer and the selenization of Mo contact layer. Properly adjusting the annealing time at an optimized heating rate is proven to successfully eliminate the fine-grain layer and obtain high quality CZTSSe thin films with large-size grains. Based on the observations, growth mechanisms for the microstructure development during selenization of solution processed Cu2ZnSnS4 films are suggested. Finally, CZTSSe device efficiency of 9.24% is achieved at an optimal selenization condition.

We report a facile electroless chemical deposition (ECD) method to deposit uniform Pd nanoparticles ((2.5 ± 0.6) nm) on CeO2 nanorods (PdNPs/CeO2-ECD) through the interface redox reaction between the reduced CeO2 and Na2PdCl4. PdNPs/CeO2-ECD exhibits a stronger electronic metal–support interaction (EMSI) evidenced by higher reducibility and stronger anti-sintering capability at high temperatures, compared to that prepared by the conventional impregnation method. Such an EMSI effect of PdNPs/CeO2-ECD significantly improves its catalytic activity in CO oxidation. Besides, the chlorine residue-free catalysts through ECD process avoid the deleterious effect of chlorine on CO oxidation. This ECD process can further be extended to deposit various uniform nanoscaled noble metals (Au, Ag, Pt, Ru, Rh, etc.) on CeO2, which may deliver their potentials in advanced catalysis.

Inorganic halide perovskite CsPbI2Br has attracted tremendous attentions in the photovoltaic fields in view of its improved ambient phase stability and reasonable band gap (1.91eV). Traditional one-step solution-processed CsPbI2Br absorbers, however, usually suffer from poor morphology, low crystallinity and thin thickness, which impede further promotion of device performance. Herein, an anti-solvent assisted multi-step deposition strategy for high-quality CsPbI2Br film is demonstrated, wherein different anti-solvents are first introduced in the PbI2 precursor filming processes to construct porous PbI2(DMSO) films. Then CsBr solution intercalates into the porous PbI2(DMSO) film by multi-step deposition, effectively facilitating the close contact of reactants and complete annealing reaction. CsBr drops and porosity degree of PbI2(DMSO) film are found to control the final morphology and phase composition of the perovskite film. Utilizing green ethanol (EtOH) treated PbI2 film with high porosity and randomized orientation, highly pure-phase and full-coverage CsPbI2Br films with high thickness, large grain sizes and high crystallinity are obtained after optimizing CsBr drops. Finally, carbon-based all-inorganic planar perovskite solar cells (PSCs) with absorbers prepared through above methods achieve a champion efficiency of 10.21%, which is a record value for the CsPbI2Br PSCs without hole transport layer. More importantly, the unencapsulated all-inorganic CsPbI2Br device shows a promising long-term stability with no obvious efficiency degradation when exposed in ambient atmosphere with 15–30% relative humidity (RH) at room temperature for 44 days.

To the requirements of introducing holes for the structural applications of bamboo scrimber, the bending properties of bamboo scrimber, which used Moso bamboo as the raw material, with holes in different sizes at different positions were studied and compared. The results indicated that drilling holes cause the decrease of the bending properties and the larger size for drilling holes causes the lower bending properties. The positions for drilling holes cause the change of the stress distribution and then decrease the bending properties. According to the comparisons of different bamboo tested samples, two basic failure modes were proposed, one is the split along the direction of bamboo fibers around the holes caused by shear stress, and the other is the fracture at the bottom of the tested samples by bending stress.

An environmentally friendly method to prepare new-generation green primary explosives with excellent performances has been developed on the basis of a coordination chemistry strategy. In the present work, constructing energetic coordination polymers (ECPs) based on tetrazole oxide 1H,1′H-[5,5′-bitetrazole]-1,1′-diol (H2BTO) with non-heavy metal cations Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) led to five novel green primary explosives without metal ion and organic pollution. Systematic research is conducted to prove these green ECPs as a novel class of lead-free primary explosives. For example, a thermal stability experiment shows that their thermal decomposition temperatures are all beyond 200 °C, while the thermal-resistance experiment demonstrates that compounds 1 and 5 can maintain long-term stability under 100 °C. And the results based on sensitivity tests and detonation parameter simulation reveal that all these compounds possess excellent detonation and safety properties, far outperforming classical primary explosives such as lead azide. Moreover, a modified Koenen test has been conducted to characterize the explosion capacity of these ECPs and by this method compounds 1, 2, 3, and 5 were demonstrated with fast deflagration-to-detonation transition ability.

All wind-driven generators need to be equipped with brakes to ensure operational control and safety. Many methods are available to avoid over-speed of the blower. This paper establishes a mechanics model to investigate each point on turbine blades, which are such designed that they would change shape in high winds to reduce the frontal area through adaptive and flexible deformation. In this way, high wind speeds will cause deformation of the blades and decrease of the rotational speed, as a result the turbine slows down. A numerical analysis of the fluid in the fan housing and a force analysis of the blades are performed, and numerical results are used to design the non-uniform arrangement of the hybrid glass/carbon fiber. A wind tunnel experiment is performed on the new blade design. The experimental results show that the new blade achieves an improvement in its mechanical properties and is able to adaptively adjust the torque. During the operation of the wind-driven generator, the new blade could effectively broaden the operational range of wind speeds, thereby improving the power generation when the wind speed is low. A generator without a brake stalls when the wind speed exceeds 13 m/s. After the adoption of the self-adaptive blade made up of the uniform-section complex textile material, the power set shows reduction of noise, avoidance of blade runaway, improvement of the efficiency of the power generation, decrease of cost and enhancement of blade consistency.

Nanomaterials with high catalytic activity and good SERS properties can be used for sensitive and real-time in situ tracking of a catalytic process via SERS, which can be a powerful tool for investigating the products and mechanisms of the catalytic reaction. In the present work, Au@AgPt NPs with a {431}-faceted hexoctahedral Au core and an AgPt alloy shell exhibiting enhanced catalysis and good SERS activity were prepared by a facile silver-mediated temperature-controlled selective deposition of Pt. The complex hexoctahedral Au nanoparticles were synthesized first as nano-templates, followed by coating with a thin layer of Ag. Then, a temperature-controlled synthesis method for preferably depositing Pt on the hexoctahedral Au NPs was proposed to prepare Au@AgPt NPs. With the increase of the synthesis temperature, the Pt atoms were controlled to selectively deposit on the tips, edges or the entire surface of the nano-templates. By systematically investigating the effects of temperature, precursor consumption and synthesis time on the morphology, composition, optical properties, catalysis and SERS properties of the Au@AgPt NPs, the kinetic and thermodynamic mechanisms of the deposition of Pt on hexoctahedral Au nanoparticles were explored. The performance of the Au@AgPt NPs in SERS-based real-time in situ monitoring of the catalytic reaction was also investigated and verified. Besides, it is easy to regulate and control their SERS and catalytic performances through the selective deposition of Pt, according to the demand of the catalytic reaction and SERS monitoring. This work not only presents a new Au@AgPt nanostructure with good catalytic and SERS properties, but also develops a facile, universal and controllable method for selective deposition of Pt on Au nano-templates with a variety of morphologies.

A novel method was developed to uniformly disperse sub-micron TiO2 opacifier into fiber reinforcements using agar and silica as binders via freeze drying. TiO2 opacifier/ fiber/ alumina-based aerogel ternary (TFA) composites with high strength and excellent high-temperature thermal insulation were successfully prepared by sol-gel route, impregnation process and supercritical fluid drying. The microstructure, mechanical and thermal insulation properties of TFA composites were investigated comprehensively. The results show that the mechanical property of TFA composites can be significantly enhanced by mullite fiber felt and the incorporation of SiO2 binder. The effect of TiO2 opacifier on the high-temperature thermal conductivity was studied by adjusting the content of TiO2 from 0 to 15 wt%. The obtained TFA composites exhibit high Young's modulus of up to 3.58 MPa and low high-temperature thermal conductivities of 0.129 W/m·K at 800 °C and 0.168 W/m·K at 1000 °C, respectively. The mechanism of heat transfer in TFA composites at high-temperature was also analyzed.

The extraordinary high pressure and temperature produced during cavitation is crucial for ultrasonic sonochemistry. However, the cavitation effect is usually confined to a small zone nearby the ultrasonic horn, outside of which ultrasound produces much less effects on chemical reaction. In present work, in order to expand the range of effective zone and intensify the cavitation effect, N2 aeration was introduced to an ultrasonic polymerization process of CuO@PNIPAM in aqueous solution. By increasing the number of bubble nucleus gathered on the CuO surface and lowering the surface tension of the aqueous solution, the cavitation effect is intensified on the CuO surface within the whole reaction vessel, which benefits the covalently bonding between PNIPAM and CuO to a large degree and results in the formation of CuO@PNIPAM hybrid composite with excellent interfacial bonding. It is promising that the hybrid composite can be applied as temperature responsive glucose sensing platform with ON and OFF states due to the wettability change of PNIPAM versus temperature.

This work aims at developing an energy-efficient process for production of high strength hot-rolled quenching and partitioning (Q&P) steel. A novel processing strategy involving quenching above martensite start temperature (Ms) in combination with dynamic carbon partitioning is first proposed for hot-rolled Q&P process. The alloy 0.25C-3Mn-2Al (wt%) was intentionally designed to low interface mobility during slow cooling in bainite range and thus controlled partial bainite transformation. Finally, multi-phases containing ferrite, martensite and nano-sized retained austenite were obtained and an improved mechanical property can be achieved with tensile strength ∼1096 MPa and uniform elongation ∼16%. This work breaks the Q&P constraint with quenching temperature below Ms and provides an easy-industrialized processing route.

In order to study the structure and analyze the performance, a series of BaWO4 with different Sm3+-doped concentration crystal particles were synthesized successfully via a low temperature molten salt method in LiNO3-KNO3 molten salt systems. For structural characterization, the phase and morphology of as-prepared powders were detected by XRD and SEM. It was clear that octahedron-type particles confirmed the scheelite-type tetragonal structure with space group I41/a. The effect of different contents of Sm3+ on the BaWO4 crystal structure was studied by Rietveld refinement techniques and the change of the optical band gap. As for the luminescent properties, the Sm3+ doped phosphors under 403 nm (6H5/2-4F7/2) excitation, exhibited characteristic luminescent of 4G5/2-6H5/2, 6H7/2, 6H9/2 transition of the Sm3+ ion. It was found that the optimal concentration involved in luminescence was about 3mol%. The critical distance between the Sm3+ ions was 1.852 nm. The mainly dominant mechanism of concentration quenching and corresponding CIE color coordinate were elaborated in details. These results indicated as-prepared phosphors could be suitable as single-doped yellow light emitters with only single-phased for solid state lighting applications.

The plasma-assisted method was used to synthesize silver nanoparticles, and the growth process of silver nanoparticles (Ag-NPs) was monitored in real time by localized surface plasmon resonance (LSPR) absorption spectroscopy. The effect of additives on the synthesis of Ag-NPs was verified. It is found that the addition of isopropanol and glucose can increase the plasmon resonance absorption intensity of the reaction solution, and promote the synthesis of Ag-NPs. In the plasma-assisted method, the additives can effectively improve the synthesis efficiency of Ag-NPs, which has great inspiration for the synthesis of other metal nanoparticles.

Terahertz waves play an increasingly important role in the areas about astronomical exploration and imaging due to its unique atmosphere sensitivity and space transmission property. In order to realize high sensitive terahertz detection, we develop mesa-type silicon-based blocked-impurity-band (BIB) terahertz detectors. For further verify the influence of device structure parameters on the performance of the BIB detectors, the different doping concentration of absorption layer was fabricated. Moreover, the influence of various doping conditions on the performance of BIB terahertz detector were analyzed. Then the blackbody responsivity and response spectral performance were measured at 4K liquid helium cryogen temperatures. The results show the blackbody responsivity is proportional to the doping concentration of the absorption layer within a range. When the doping concentration increase to a certain degree, the bandgap narrowing effect will become obvious, which results to the impurity band and bottom of the conduction band degeneracy and the function of the device will be invalid. According to the measurement results, when the doping concentration of the absorption layer is 7*1016cm-3, the BIB terahertz detector we fabricated has the optimal blackbody responsivity and response spectral performance, and its peak responsivity can reach 15.4A/W. As a further step, the focal plane arrays mesa-type silicon-based BIB terahertz detectors will be designed.