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Hundreds of C60 derivatives stand out as electrontransporting materials(ETMs), for example, in perovskite solar cells(PSCs), due to their properties on electron extraction or defect passivation. However, it still lacks of guidelines to update C60-based ETMs with excellent photoelectric properties. In this work, crystallographic data of eight C60-based ETMs, including pristine C60 and the well-known PCBM as well as six newly synthesized fullerenes, are analyzed to establish the connections between derivatized structures and photoelectric properties for the typical carbon cluster of C60. In terms of packing centroid-centroid distance between neighboring carbon cages, the crystallographic data are useful for probing photoelectric properties, such as electrochemical properties, electron mobility and photovoltaic performances, and therefore facilitate to design novel C60-based ETMs for PSCs with high performances.

The rate-dependent mechanical properties of a specific geomaterial play a crucial role in engineering design and application. However, there have been very few studies involving rate-dependent mechanical properties of calcareous sand particles. This present investigation aims to study the rate-dependent breakage behavior of calcareous sand particles experimentally and numerically. Experimental tests were conducted under various loading rates. Moreover, the discrete element method was utilized in particle crushing tests to assess the breakage sub-processes. The experimental results reveal that the particle crushing strengths conform to the Weibull distribution. As the loading rates increase, the fragmentation mode changes from primary splitting and successive breaking to severe disintegration, corresponding to the three types of axial force-displacement curves, namely, the quasi-hardening, the slight quasi-softening, and the obvious quasi-softening. The simulation results show that the fractures initiate in the vicinity of contact point between the particle and loading walls, eventually penetrating through the particle along the vertical section of the sample. A higher loading rate may lead to a greater extent of particle breakage. The findings presented in this study may advance the understanding of the rate-dependent mechanical properties of calcareous sands.

Plasma can be used to effectively remove coke from a metal surface. The plasma etching conditions of coke and emission spectrum characteristics on the metal surface in a complex structure can be determined in real-time using the flexible optical fiber of an emission spectrometer. In this study, the glow discharge hydrogen plasma etching characteristics of a graphite sheet covering Cu and Fe electrodes were investigated. Methane plasma and a bare Cu electrode without graphite were used to conduct experiments for comparison. The cathode was heavily etched owing to the chemical and physical reactions of abundant H and other active species. Many hydrocarbon particle shells with fuzzy boundaries of multilayer graphite were observed on the ground electrode as black dots with diameters less than 1 micron. The cracking reaction of etching process in the case of hydrogen plasma with graphite electrodes plays a leading role, but polymerization reaction is dominant for the methane plasma with bare Cu electrodes. Significant excitation peaks of the emission spectrum are observed in regions centered at 388 and 776 nm for the etching of carbon-rich electrodes in hydrogen-rich plasma. Different hydrocarbon and metal substrate bonds can exist even under strong etching conditions.

In situ cross-linking encapsulation has been demonstrated to be an efficient strategy for enhancing the humidity stability of perovskite solar cells (PSCs). In this study, a novel cross-linkable fullerene derivative, namely 1-(p-benzoate-(p-methylvinylbenzene)-indolino[2,3][60] fullerene (FPPS), was readily synthesized from commercially available building blocks in two steps. This FPPS was employed as an interfacial modifier on perovskite surfaces in inverted planar p–i–n PSCs. Owing to the fast interfacial charge extraction and efficient trap passivation, PSCs based on the cross-linked FPPS (C-FPPS) exhibited excellent performance. The PSCs had a top-performing power conversion efficiency (PCE) of 17.82% with negligible hysteresis, compared to the control devices without C-PFFS (16.99%). Moreover, the strong water resistance of the C-FPPS interfacial layer distinctly enhances the ambient stability of PSC devices, exhibiting a t80 (the time required to reach 80% of the initial PCE) of 300 h under high-humidity conditions. This significantly surpasses the control devices, whose t80 was only 130 h. These results demonstrate that cross-linkable fullerene derivatives can be promising interfacial materials for designing high-efficiency, hysteresis-free, air-stable PSCs.

This paper uses the discrete element method to model the size and cushion effects during single-particle crushing tests. We propose simplified numerical modeling to examine the effects of particle size and coordination number on particle breakage behavior. We validate the proposed modeling by comparing the numerical results with the experimental data reported in the literature, in terms of the variability of particle tensile strength and axial force–displacement responses. Based on the numerical results, it is clear that a larger particle size entails a higher tensile strength with a larger discreteness. In addition, the characteristic tensile strength increases linearly with an increasing coordination number. Moreover, smaller particles are more susceptible to the cushion effect than larger particles. The numerical results also indicate that an increasing coordination number induces a more ductile mode of failure. Based on these results, we propose an empirical equation for calculating tensile strength, incorporating both the cushion effect and the size effect.

Multi-walled carbon nanotubes (MWNTs) were prepared by pyrolysis of cheap natural gas over Ni/La2O3-MgO catalyst at 740 °C. The purified MWNTs were easily dispersed by ball milling method and aqueo...

Multi-walled carbon nanotubes (MWNTs) with high-yield were prepared by pyrolysis of mixture of natural gas (NG) and propylene (C3H6) over Fe-Ni/Al2O3-MgO catalyst. For C3H6/NG flow rate ratio rangi...

The structure-dependent thermal stability of fullerene electron transport layers (ETLs) and its impact on device stability have been underrated for years. Based on cocrystallographic understanding, herein, we develop a thermally stable ETL comprising a hybrid layer of [6,6]-phenyl-C

Article Highlights By low-temperature aging, superior bromine-free FA1–xMAxPbI3 perovskite film is realized.By suppressing lead iodide on the surface of perovskite, no further passivation step or layer is needed. The efficiency of planar perovskite solar cells is improved to 22.41% with robust reproducibility. Electronic supplementary material The online version of this article (10.1007/s40820-020-00418-0) contains supplementary material, which is available to authorized users., Previous reports of formamidinium/methylamine (FAMA)-mixed halide perovskite solar cells have focused mainly on controlling the morphology of the perovskite film and its interface—for example, through the inclusion of bromine and surface passivation. In this paper, we describe a new processing pathway for the growth of a high-quality bromine-free FAMAPbI3 halide perovskites via the control of intermediate phase. Through low-temperature aging growth (LTAG) of a freshly deposited perovskite film, α-phase perovskites can be seeded in the intermediate phase and, at the same time, prevent beta-phase perovskite to nucleate. After postannealing, large grain-size perovskites with significantly reduced PbI2 presence on the surface can be obtained, thereby eliminating the need of additional surface passivation step. Our pristine LTAG-treated solar cells could provide PCEs of greater than 22% without elaborate use of bromine or an additional passivation layer. More importantly, when using this LTAG process, the growth of the pure alpha-phase FAMAPbI3 was highly reproducible. Electronic supplementary material The online version of this article (10.1007/s40820-020-00418-0) contains supplementary material, which is available to authorized users.

Single particle crushing tests were conducted to investigate the size effect on the crushing behaviors of single calcareous sand particles experimentally and numerically. The particle crushing stre...

Antisolvent-assisted crystallization is adopted widely in the preparation of double-cation [e.g., cesium/formamidinium (Cs/FA), formamidinium/methylammonium (FA/MA)] and triple-cation (e.g., Cs/FA/MA) FA-based perovskite solar cells (PSCs) to enhance their power conversion efficiencies (PCEs) and device stability. Although many antisolvents have been applied to treat various perovskites with different compositions, their crystallization mechanisms have remained unclear. In this study, we investigated the effects of a series of green antisolvents—namely, the ethers diethyl ether, anisole, diisopropyl ether (DIE), and dibutyl ether—on the crystallization of perovskites. We found that the formation of an intermediate phase was heavily determined by the antisolvent's polarity. Indeed, through judicious control of the antisolvent's polarity, it was possible to form a pure intermediate phase, without a PbI2 or perovskite phase. Upon thermal annealing, the crystallization of perovskites was improved. Understanding the mechanism of formation of the intermediate phase led us to identify DIE as a green antisolvent with universal perovskite compatibility, achieving champion PCEs of 20.05%, 20.15%, and 21.26% for Cs/FA, FA/MA, and Cs/FA/MA, respectively. The PCE of large-area (1 cm2) PSCs reached 18.51%. Furthermore, the repeatability of these champion PCEs was greatly improved. This work contributes to the understanding of antisolvent's polarity as an important factor affecting the formation of a pure intermediate phase of FA-based perovskites, which also offers a greener approach for the production of PSCs.

Lots of research have focused on the core/shell structure nanocomposites owing to their synergistic effect that were considered as the most promising high-performance microwave absorbers (MAs). How...

Summary Core structures with linear, planar, and spiral conformations have been designed as triphenylamine (TPA)-based hole-transporting materials (HTMs), which are the most prevalent small molecular HTMs in perovskite solar cells (PSCs). However, most of the reported TPA-based HTMs cannot achieve sufficient balance between efficiency and stability, which is governed by core structures. Herein, a sym-penta(N,N-bis(4-methoxyphenyl)aniline)corannulene (cor-OMePTPA) featuring a corannulene core and five TPA peripheral arms is designed as alternative HTM. Planar negative-intrinsic-positive (n-i-p) PSCs with cor-OMePTPA exhibit champion efficiencies of 20% and maintain 86% of their initial performances for more than 1,000 h after thermal annealing at 60°C. Compared with spiro-OMeTAD, cor-OMePTPA-based PSCs show slightly lower efficiencies but much better thermal stabilities. The main merit of cor-OMePTPA lies in its bimolecular interpenetration capability with noncovalent interactions to modulate the HTM configurations from single-molecular curvature to bimolecular planarity, thereby providing promising opportunities to achieve excellent balance between efficiency and stability.

Background There has been a surge of interest on velocity-based training (VBT) in recent years. However, it remains unclear whether VBT is more effective in improving strength, jump, linear sprint and change of direction speed (CODs) than the traditional 1RM percentage-based training (PBT). Objectives To compare the training effects in VBT vs. PBT upon strength, jump, linear sprint and CODs performance. Data sources Web of science, PubMed and China National Knowledge Infrastructure (CNKI). Study eligibility criteria The qualified studies for inclusion in the meta-analysis must have included a resistance training intervention that compared the effects of VBT and PBT on at least one measure of strength, jump, linear sprint and CODs with participants aged ≥16 yrs. and be written in English or Chinese. Methods The modified Pedro Scale was used to assess the risk of bias. Random-effects model was used to calculate the effects via the mean change and pre-SD (standard deviation). Mean difference (MD) or Standardized mean difference (SMD) was presented correspondently with 95% confidence interval (CI). Results Six studies met the inclusion criteria including a total of 124 participants aged 16 to 30 yrs. The differences of training effects between VBT and PBT were not significant in back squat 1RM (MD = 3.03kg; 95%CI: -3.55, 9.61; I2 = 0%) and load velocity 60%1RM (MD = 0.02m/s; 95%CI: -0.01,0.06; I2 = 0%), jump (SMD = 0.27; 95%CI: -0.15,0.7; I2 = 0%), linear sprint (MD = 0.01s; 95%CI: -0.06, 0.07; I2 = 0%), and CODs (SMD = 0.49; 95%CI: -0.14, 1.07; I2 = 0%). Conclusion Both VBT and PBT can enhance strength, jump, linear sprint and CODs performance effectively without significant group difference.

In regular perovskite solar cells (PSCs), the commonly used electron transport layer (ETL) is titanium oxide (TiO2). Nevertheless, the preparation of a high-quality TiO2 ETL demands an elevated-tem...

A type-II heterojunction photocatalyst H3PW12O40/TiO2-g-C3N4 is obtained by ultrasonic method. The structure, morphology and optical property of the composites are studied by a series of characterizations. 20 wt.% H3PW12O40/TiO2-g-C3N4, the optimum composite, has superior photocatalytic efficiency for degrading rhodamine B (RhB) and p-nitrophenol (PNP) under visible light irradiation. The photocatalytic performance improvement of H3PW12O40/TiO2-g-C3N4 ternary composite material is ascribed to enhanced adsorption capacity of organic contaminants and efficient separation of photoinduced carriers. Furthermore, we can conclude that h+, O2−, and OH are the major active substances in the photocatalytic degradation process, which further provides the evidence for superior photocatalytic activity of H3PW12O40/TiO2-g-C3N4 composite material compared to bare g-C3N4. The H3PW12O40/TiO2-g-C3N4 composite displays excellent stability and recyclability, which can be reused for four times with only slight inactivation. Overall, this work puts forward a new direction for the fabrication g-C3N4-based visible-light-driven photocatalytic composite materials.

Three-dimensional (3D) titania (TiO2) hollow spheres doped with rare earth elements were successfully synthesized via a nonhydrolytic sol-gel method using lotus pollen as a biotemplate and a cationic surfactant as a co-template. The as-prepared samples were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, nitrogen adsorption-desorption isotherms, photodegradation tests, and UV-vis diffuse reflectance spectroscopy. The results indicate that the 3D TiO2 hollow spheres have a structure similar to that of lotus pollen. The Brunauer-Emmett-Teller specific surface areas of 3D TiO2 and 3D Gd-La–co-doped TiO2 are 94.90 and 88.62 m2g-1, respectively, which are higher than for a commercial TiO2 sample (P25). In addition, 3D TiO2 in combination with rare earth element co-doping can extend light absorption to the visible region and enhance photocatalytic activity for the degradation of methyl orange under simulated solar irradiation as compared with P25 and pristine 3D TiO2. The superior photocatalytic activity is mainly attributed to the higher specific surface areas and the doping with rare earth elements.

In order to obtain the excellent comprehensive properties of microwave absorbers (MAs), core@shell structured Co0.6Fe2.4O4@MoS2 nanocomposites were elaborately constructed and synthesized by a facile two-step hydrothermal method. Due to the independence of the two-step processes, the method could be applied to produce different categories of MoS2 based nanocomposites. The obtained results demonstrated that the as-prepared Co0.6Fe2.4O4@MoS2 nanocomposites exhibited superior electromagnetic wave absorption performances with very low minimum reflection loss (RLmin) value and broad absorption bandwidth at thin matching thicknesses. Impressively, the optimal RLmin value reached −79.9 dB at 11.2 GHz with a thickness of 2.73 mm, and an effective bandwidth of 5.96 GHz was observed with thicknesses of 2.34 and 2.98 mm. Taking into account their the low cost of production, high stability and controllability, the obtained results demonstrated that the Co0.6Fe2.4O4@MoS2 nanocomposites achieved in this study are very attractive candidates for new types of high performance MAs. Moreover, we believe that constructing core@shell structured MoS2-based nanocomposites is a reliable strategy to accelerate advancements of MAs.

Fire-loaded cementitious material such as concrete experiences a rapid and dramatic pore pressure buildup, resulting in potential explosive spalling—sudden loss of the heated section—which can jeopardize the structure. Pore pressure buildup processes in heated concrete are closely related to the relative permeabilities of concrete to gas and liquid denoted by $k^{rg}$ and $k^{rl}$, respectively. While $k^{rg}$ has been widely investigated experimentally, $k^{rl}$ is conventionally determined by semi-analytical meth-ods such as Mualem's model, the reliability of which has been questioned by indirect experimentation but is not fully understood. In this work, we discuss the potential overestimation of $k^{rl}$ by conventional model in consideration of the achievements of previous research. Then, by using different models, the influences of $k^{rl}$ on the pore pressure $p^g$ are shown and compared through numerical simulations with a well established thermo-hydro-chemical (THC) multifield framework, revealing that the conventional model provides smaller values of $p^g$ than other models. Finally, through a comparison with water con-tent results obtained from nuclear magnetic resonance (NMR) tests in publications [ 1 ], we prove that some other models produce results that are more agreeable than those of the conventional model, which cannot reproduce the steep increase in the moisture content with depth observed experimentally.

The purpose of this paper is to propose magnetorheological fluid-lubricated rubber stern bearing test ring, to study the effects of temperature, magnetic field strength and eccentricity ratio on lubrication performance. The Reynolds equation considering effects of eccentricity ratio, temperature and magnetic field strength is adopted and solved by finite difference method and successive over-relaxation method to calculate pressure distribution and friction coefficient with real bearing shapes and boundary conditions. Bearing capacity can be improved and friction coefficient can be reduced by decreasing temperature, increasing magnetic field strength and increasing eccentricity ratio. The paper’s results may provide important design theoretical and experimental guidelines support for rubber stern bearing in this kind of magnetorheological fluids-lubricated.

In p-i-n structure perovskite solar cells (PSCs), the most prevalent electron transport layer (ETL), [6, 6]-phenyl-C61-butyric acid methyl ester (PC61BM), acts as both electron extractor and protective coverage to the underlayer perovskite. Notably, multifunctional mixed fullerene ETLs show great potential in further improving both the power conversion efficiency (PCE) and stability of PSCs compared to the single PC61BM ETL. In this work, we reported the mixed fullerene ETLs comprising of PC61BM and its two analogs with different length of fluorocarbon chains, [6, 6]-phenyl-C61-buryric acid 1H,1H-trifluoro-1-ethyl ester (abbreviated, CF3-PC61BM) and [6, 6]-phenyl-C61-buryric acid 1H, 1H-tridecafluoro-1-heptyl ester (abbreviated, C6F13-PC61BM). We obtained excellent PCEs of 18.37% and 17.71% for 1 wt % CF3-PC61BM- and C6F13-PC61BM-based PSCs (1 wt % addition of PC61BM) with CH3NH3PbI3 (MAPbI3) perovskites, respectively. Moreover, champion PCEs of ∼19% were obtained based on the CsFAMAPbIBr perovskites. Subsequent experiments demonstrated that the fluorocarbon chains of CF3-PC61BM and C6F13-PC61BM assembled at the surfaces of ETLs with the formation of thin-layer moisture-resistant protective coverage above perovskite. Results show that it significantly retarded water penetrating down to perovskite layers and led to optimal humidity stability under ambient atmosphere.

Nanoporous materials with core-shell structure have received lots of attention owing to the great versatility of the functional cores and shells and their potential application in catalysis and biological applications. In this work, a facile method has been developed to synthesize uniform Au@Pt@mesoporous SiO2 nanostructures with high peroxidase-like activity, which had a well-defined core-shell structure with Au nanorods@Pt nanodots as a core and mesoporous SiO2 as a shell. The mesoporous SiO2 shell can not only provide convenient transmission channels but offer a substantial location for accommodation of large biomolecules, such as antibodies and antigens. Here a novel nanoprobe based on Au@Pt@mesoporous SiO2 nanozyme modified with mumps antigens was reported. Notably, the encapsulation of Au@Pt nanorod in mesoporous SiO2 shell was able to hinder the interaction between catalytical nanoparticles and recognition antigens, retaining the catalytic activity of the inner active nanoparticle core. Furthermore, this nanoprobe exhibited an extraordinarily stability and showed excellent activity. As a result, we presented an enzyme linked immunosorbant assay (ELISA) for the diagnosis of mumps virus; this proposed method exhibited good sensitivity to mumps-specific IgM antibodies. The limit of detection can be as low as 10 ng/mL, which was more sensitive compared to the conventional immunoassay. Our results indicated that this nanoprobe hold great promise with opportunities for applications of biosensors, catalysis and biotechnology.

Endothermic hydrocarbon fuel has many advantages as a cooling medium in hypersonic aircraft; however substantial application has been greatly hindered due to easy coking, uncontrollable gas product...

Generally, bias voltage exercises a great influence on micro-properties (morphology, preferred orientation, mechanical properties, and so on) of the coatings in the process of coating deposited. In order to more systematically explore the influence of bias voltage on microstructure, hardness and adhesion of TiN coatings, TiN coatings were deposited successfully on the surface of 316 stainless steel by high power pulsed magnetron sputtering (HPPMS). A field emission scanning electron microscopy equipped with energy dispersive spectrometer (FESEM/EDS) and an X-ray diffractometer were employed to analyze the surface morphology, chemical composition and phase structure of coatings, respectively. And a nanoindentation and scratch tester was used to investigate the hardness, elastic modulus and adhesion of TiN coatings. Results showed that bias voltage has a great influence on surface morphology of TiN coatings. Moreover, bias voltage can promote preferential orientation and the phase in TiN coating is mainly TiN with a small amount of Ti2N. The influence of bias voltage on the hardness and modulus of TiN coating is not obvious, however, the binding force increases fast first and then decreases slow with the increase of bias voltage. TiN coating has excellent performance when bias voltage is-100V.

Interface engineering that involves in the metal cathodes and the electron transport layers (ETLs) facilitates the simultaneous improvement of device performances and stability in perovskite solar cells (PSCs). Herein, low-temperature solution-processed cerium oxide (CeOx) films are prepared by a facile sol-gel method and employed as the interface layers between [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) and an Ag back contact to form PC61BM/CeOx double ETLs. The introduction of CeOx enables electron extraction to the Ag electrode and protects the underlying perovskite layer and thus improves the device performance and stability of the p-i-n PSCs. The p-i-n PSCs with double PC61BM/CeOx ETLs demonstrate a maximum power conversion efficiency (PCE) of 17.35%, which is superior to those of the devices with either PC61BM or CeOx single ETLs. Moreover, PC61BM/CeOx devices exhibit excellent stability in light soaking, which is mainly due to the chemically stable CeOx interlayer. The results indicate that CeOx is a promising interface modification layer for stable high-efficiency PSCs.

Fully phenylated C60Ph6 has never been synthesized in the past two decades largely due to steric effect and poor thermodynamic stability of the initial intermediate towards its isostructural penta-phenyl adduct (C60Ph5X) that has one central site intact. Herein, we report a kinetic management strategy using nitrobenzene that can efficiently alleviate the steric effect in the substitution reaction of C60Cl6 to synthesize C60Ph6. As revealed by X-ray crystallography, the molecule of C60Ph6, in stark contrast to its isostructural C60Ph5Cl with the last chlorine intact, shows a favorable geometrical structure and molecular stacking for electron transport. Furthermore, C60Ph6 shows high LUMO energy of −3.51 eV (0.4 eV higher than that of [6,6]-phenyl-C61-butyric acid methyl ester, PCBM), which is promising high open-circuit voltage for organic solar cells. The merits of both molecular packing and electrochemical property of C60Ph6 lead to high open-circuit voltage of 1.04 V for the OSC device based on poly(3-hexylthiophene) (P3HT). The present C60Ph6 exemplifies a novel class of electronic acceptors with fully aromatized groups on a fullerene cage.

Coolant heat transfer capacity determines the security of avionics system operation. Electrohydrodynamics (EHD), as an enhanced heat transfer technology, can be applied to the avionics cooling system. In this paper, the forced convection heat transfer characteristics of aviation kerosene enhanced by the EHD technique were investigated by both experimental and numerical simulation methods for the first time. One kind of wire-tube structure heat exchanger was designed and the heat dissipation performance of aviation kerosene was tested experimentally at different inlet parameters and electric potentials. A 3D mathematical model was established based on Maxwell and Navier-Stokes equations and the finite volume method was used for conservative discretization of the governing equations. The experimental and numerical simulation results are in good agreement. In the range from 128 to 900 of Reynolds number, the EHD heat transfer enhancement effect becomes weaken with the increase of mass flow. The charge migration along the electric field is suppressed due to the increasing axial velocity. However, the heat transfer enhancement effect is more obvious with the increasing inlet temperature of aviation kerosene. Due to the low viscosity and high ion mobility of high-temperature aviation kerosene, the charge migrating ability is enhanced and the viscous resistance is easier to overcome to produce the secondary flow. The maximum heat transfer enhancement ratio can reach 1.9 times. This paper expanded the EHD application to aviation fuels as the coolant in avionics systems and provided a deeper understanding on inlet parameters affecting the EHD heat transfer enhancement.

The one-dimensional plug flow reactor (PFR) model is commonly used in regenerative cooling simulations. However, the extreme operational conditions in regenerative cooling channels may affect the predictive accuracy of PFR, in which the effects of turbulent flow and heat transfer were not considered. In this study, we compared the chemical reaction predictions from PFR and Computational Fluid Dynamics (CFD) in regenerative cooling channels, and studied the effects of the main operating conditions on predictive accuracy, namely: pressure, flow rate, and heat flux. Experiments were performed to validate the CFD model and illustrate the predicative deviations in PFR under different operating conditions. Additional simulations with special operational conditions were also carried out to analyze the key factors. Results revealed that turbulence and radial temperature heterogeneity caused by turbulent flow and convective heat transfer influenced the pyrolysis predictions in different ways. The intensities of the two competitive effects changed with the operating conditions, which affect the accuracy of PFR model. Besides, the importance of heat transfer effects was emphasized in predicting the changing regularity of heat sink. This work is expected to provide novel understandings of reacting flow to engineering applications.

Monodisperse nickel phosphide (Ni5P4) nanoparticles supported on carbon (Ni5P4@C) were in situ synthesized by one step solution-phase route, in which the mixture of trioctyloxide (TOPO) and trioctylphosphine (TOP) was used as solvent, capping agent and phosphor source. Ni5P4nanocrystals were in situ coupled by active carbon simply adding the carbon to the reaction solution. The as-prepared Pt-free Ni5P4 nanocrystals exhibit the enhanced electrocatalytic activity toward hydrogen oxidation reaction (HOR) compared to pure commercial Ni nanoparticles. Therefore, the obtained Ni5P4@C nanocatalyst appears to be promising non precious metal electrocatalysts for HOR.

Organic–inorganic perovskite solar cells have emerged as a promising photovoltaic technology because of their advantages such as low cost, high efficiency, and solution processability. The performance of perovskite solar cells is highly dependent on the crystallinity and morphology of the perovskite films. Herein, we report a simple, one-step anti-solvent deposition process using di-isopropyl ether as a dripping solvent to obtain extremely uniform and highly crystalline CH3NH3PbI3 perovskite films. Compared to toluene, chlorobenzene, chloroform, or diethyl ether, di-isopropyl ether has proven to be a more suitable solvent for an anti-solvent deposition process. The perovskite solar cells fabricated by the anti-solvent deposition process using di-isopropyl ether treatment exhibit an average power conversion efficiency (PCE) of 17.67 ± 0.54% and the highest PCE of 19.07%. Moreover, the higher boiling point of di-isopropyl ether makes the anti-solvent deposition process more tolerant to elevated ambient temperature, which can be carried out at ambient temperatures up to 40 °C. Our results demonstrate that di-isopropyl ether is an excellent dripping solvent in the anti-solvent deposition process for efficient and reproducible perovskite solar cells.

In high performance perovskite solar cells (PSCs), the electron transport layer (ETL) has overwhelmingly been dominated by compact titanium oxide (TiO2), which typically requires sintering at around 500 °C. Such a high-temperature sintering procedure prevents TiO2-based PSCs from matching well with plastic substrates and low-cost manufacturing. Here we report cerium oxide (CeOx, x = 1.87), that was prepared facilely through a simple sol–gel method at low temperature (∼150 °C), as an alternative to high-temperature sintering processed TiO2 in the regular architecture of PSCs. With a PCE of 14.32% from the involvement of an optimized CeOx ETL through adjusting the precursor solution, and a higher PCE of 17.04% through introducing a [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) interfacial layer between the CeOx ETL and the perovskite layer, the present work about CeOx-based PSCs renders low-temperature solution-processed CeOx an excellent ETL for high performance perovskite solar cells with improved stability.

For the purpose of inhibiting carbon deposition in the low-temperature oxidation process of aviation fuel in the fuel injector, a new multi-field coupling method was proposed. 95% pure n-pentane was selected as the experimental fuel. A needle-tube flow reactor that could provide a high voltage environment was designed. Thermal oxidation deposits under the voltage from 0 V to 5000 V were compared at inlet fuel temperature of 600 K. The deposits on the wall and the electrode of the reactor under different voltages were measured by scanning electron microscope (SEM) and temperature programmed oxidation (TPO). The experimental results show that the discharge can reduce the diameter of the deposits and with the increase of the voltage, the maximum coke formation on the reactor wall was reduced by 19.01%. Through oxygen content analysis, the discharge consumed more dissolved oxygen. The flow field in the reactor was studied by numerical simulation. Maxwell and Navier-Stokes equations for a three-dimensional physical model were solved by the finite volume method. The secondary flow and the increased velocity caused by the discharge retarded the accumulation of deposits. This paper used the fuel stable discharge phenomenon to provide new means for suppressing the oxidation deposition.

Perovskite solar cells (PSCs) with TiO2 materials have attracted much attention due to their high photovoltaic performance. Aligned TiO2 nanorods have long been used for potential application in highly efficient perovskite solar cells, but the previously reported efficiencies of perovskite solar cells based on TiO2 nanorod arrays were underrated. Here we show a solvothermal method based on a modified ketone-HCl system with the addition of organic acids suitable for modulation of the TiO2 nanorod array films to fabricate highly efficient perovskite solar cells. Photovoltaic measurements indicated that efficient nanorod-structured perovskite solar cells can be achieved with the length of the nanorods as long as approximately 200 nm. A record efficiency of 18.22% under the reverse scan direction has been optimized by avoiding direct contact between the TiO2 nanorods and the hole transport materials, eliminating the organic residues on the nanorod surfaces using UV-ozone treatment and tuning the nanorod array morphologies through addition of different organic acids in the solvothermal process.