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The nature and complexity of the manufacturing process for composite coatings make it difficult to predict or even measure the technical and economic performance of manufacturing, which is why great attention has been paid to the manufacturing methodologies of these coatings and their properties, in particular the mechanical properties. In this work, an experimental approach for the manufacture of Ni–P–Y2O3 composite coatings by cathode process from sulfate-based electrodeposition baths was presented. This approach can improve the mechanical properties of the coating and the rate of deposition exhibited by the cathode current efficiency. A new technique for identifying processing parameters using a multi-input–output system based on the technique of multiple linear regression has been proposed. The objective was to determine the influence of the electrodeposition parameters on the quality of the coatings developed in order to conduct an optimization based on the genetic algorithm of these parameters that ensures the obtaining of a high micro-hardness coating, with the maximum possible efficiency of the electrodeposition cell. It is shown that the elaborated model is able to give results providing a very good correlation between the real and predicted values, and the experimental results were found to be close to the predicted values within 1.95% error range for cathode current efficiency and 1.58% error range for micro-hardness. The values used for the validation of the elaborated models differ from the values used for the construction of the fuzzy rules. The new optimization strategy used in this study made it possible to determine the optimal values that allow obtaining a coating with high micro-hardness (592 Hv) compared to other coatings of the same family with a high efficiency of electrodeposition cell.

This study explores the electrochemical reduction of carbon dioxide (CO2) using tin (Sn) and zinc (Zn) catalyst-loaded gas diffusion electrodes (GDEs). The research explores the influence of electrolytic potential and catalyst loading on the efficiency of CO2 conversion to valuable chemicals, specifically formic acid and carbon monoxide. The best Sn loading for Sn-loaded GDEs, according to the morphological study, is 7 mg.cm-2, which results in higher current density (0.33 mA.cm-2) and current efficiency (36%). An electrolytic potential of -1.3 V Vs. Ag/AgCl is identified as optimal for Sn GDEs, offering a balance between high current efficiency (35%) and controlled current density. For Zn-loaded GDEs, an optimal loading of 5 mg.cm²- yields the highest current efficiency of 19.4% and a peak current density of 0.28 mA.cm²- at an electrolytic potential of -1.55 V Vs. Ag/AgCl, in addition to highlighting the crucial role that catalyst loading and electrolytic potential play in enhancing CO2 reduction efficiency, this research offers insightful information for environmentally friendly CO2 conversion technology.

A feasibility study was carried out on generation of hydrochloric acid and lithium hydroxide from the simulated lithium chloride solution using EX3B model bipolar membrane electrodialysis (BMED). The influence of a series of process parameters, such as feed concentration, initial acid and base concentration in device component, feed solution volume, and current density were investigated. In addition, the maximum achievable concentrations of HCl and LiOH, the average current efficiency, and specific energy consumption were also studied and compared in this paper to the existing literature. Higher LiCl concentrations in the feed solution were found to be beneficial in increasing the final concentrations of HCl and LiOH, as well as improving current efficiency while decreasing specific energy consumption. However, when its concentration was less than 4 g/L, the membrane stack voltage curve of BMED increased rapidly, attributed to the higher solution resistance. Also low initial concentration of acid and base employed in device component can improve the current efficiency. Increasing of the initial concentration of acid and base solution lowered energy consumption. Moreover, a high current density could rapidly increase HCl and LiOH concentration and enhance water movements of BMED process, but reduced the current efficiency. The maximum achievable concentration of HCl and LiOH generated from 130 g/L LiCl solution were close to 3.24 mol/L and 3.57 mol/L, respectively. In summary, the present study confirmed the feasible application for the generation of HCl and LiOH from simulated lithium chloride solution with BMED.

In this paper, to improve the current efficiency in the copper electrowinning process is taken as the research objective. In the traditional production process, sulfate ion concentration, copper ion concentration and current density are carried out according to the empirical value, which cannot ensure the current efficiency to reach the optimal level. Therefore, firstly, this paper proposes a BP neural network model to improve the current efficiency according to the relationships between sulfate ion concentration, copper ion concentration, current density and the established BP neural network model is trained by using real data from the enterprise. The simulation results indicate that there is a definite error between the predicted current efficiency and corresponding to the current efficiency measured at the production site. It is proposed that the BP neural network improved by the improved PSO to further improve the prediction accuracy of the BP neural network. Simulation results indicate that the prediction error of the current efficiency is greatly reduced that meets the accuracy requirements. On the premise of guaranteeing the quality of copper electrowinning, the current density, sulfate ion concentration and copper ion concentration corresponding to the maximum current efficiency accurately predicted by this method can be respectively adjusted in real-time in the copper electrowinning process, which realizes the optimization of current efficiency in the process of copper electrowinning under the background of low carbon and environmental protection.

Electroluminescence efficiencies of metal halide perovskite nanocrystals (PNCs) are limited by a lack of material strategies that can both suppress the formation of defects and enhance the charge carrier confinement. Here we report a one-dopant alloying strategy that generates smaller, monodisperse colloidal particles (confining electrons and holes, and boosting radiative recombination) with fewer surface defects (reducing non-radiative recombination). Doping of guanidinium into formamidinium lead bromide PNCs yields limited bulk solubility while creating an entropy-stabilized phase in the PNCs and leading to smaller PNCs with more carrier confinement. The extra guanidinium segregates to the surface and stabilizes the undercoordinated sites. Furthermore, a surface-stabilizing 1,3,5-tris(bromomethyl)-2,4,6-triethylbenzene was applied as a bromide vacancy healing agent. The result is highly efficient PNC-based light-emitting diodes that have current efficiency of 108 cd A−1 (external quantum efficiency of 23.4%), which rises to 205 cd A−1 (external quantum efficiency of 45.5%) with a hemispherical lens.Guanidinium doping is shown to enhance the operation of perovskite nanocrystal light-emitting diodes.

Organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) materials are promising for the realization of highly efficient light emitters. However, such devices have so far suffered from efficiency roll-off at high luminance. Here, we report the design and synthesis of two diboron-based molecules, CzDBA and tBuCzDBA, which show excellent TADF properties and yield efficient OLEDs with very low efficiency roll-off. These donor–acceptor–donor (D–A–D) type and rod-like compounds concurrently generate TADF with a photoluminescence quantum yield of ~100% and an 84% horizontal dipole ratio in the thin film. A green OLED based on CzDBA exhibits a high external quantum efficiency of 37.8 ± 0.6%, a current efficiency of 139.6 ± 2.8 cd A−1 and a power efficiency of 121.6 ± 3.1 lm W−1 with an efficiency roll-off of only 0.3% at 1,000 cd m−2. The device has a peak emission wavelength of 528 nm and colour coordinates of the Commission International de l´Eclairage (CIE) of (0.31, 0.61), making it attractive for colour-display applications.

Metal halide perovskites are attracting a lot of attention as next-generation light-emitting materials owing to their excellent emission properties, with narrow band emission 1 – 4 . However, perovskite light-emitting diodes (PeLEDs), irrespective of their material type (polycrystals or nanocrystals), have not realized high luminance, high efficiency and long lifetime simultaneously, as they are influenced by intrinsic limitations related to the trade-off of properties between charge transport and confinement in each type of perovskite material 5 – 8 . Here, we report an ultra-bright, efficient and stable PeLED made of core/shell perovskite nanocrystals with a size of approximately 10 nm, obtained using a simple in situ reaction of benzylphosphonic acid (BPA) additive with three-dimensional (3D) polycrystalline perovskite films, without separate synthesis processes. During the reaction, large 3D crystals are split into nanocrystals and the BPA surrounds the nanocrystals, achieving strong carrier confinement. The BPA shell passivates the undercoordinated lead atoms by forming covalent bonds, and thereby greatly reduces the trap density while maintaining good charge-transport properties for the 3D perovskites. We demonstrate simultaneously efficient, bright and stable PeLEDs that have a maximum brightness of approximately 470,000 cd m −2 , maximum external quantum efficiency of 28.9% (average = 25.2 ± 1.6% over 40 devices), maximum current efficiency of 151 cd A −1 and half-lifetime of 520 h at 1,000 cd m −2 (estimated half-lifetime >30,000 h at 100 cd m −2 ). Our work sheds light on the possibility that PeLEDs can be commercialized in the future display industry. The authors develop a method for the production of ultra-bright, efficient and stable perovskite light-emitting diodes, achieved with a simple in situ reaction process.

Perovskite light-emitting diodes (LEDs) are attracting great attention due to their efficient and narrow emission. Quasi-two-dimensional perovskites with Ruddlesden–Popper-type layered structures can enlarge exciton binding energy and confine charge carriers and are considered good candidate materials for efficient LEDs. However, these materials usually contain a mixture of phases and the phase impurity could cause low emission efficiency. In addition, converting three-dimensional into quasi-two-dimensional perovskite introduces more defects on the surface or at the grain boundaries due to the reduction of crystal sizes. Both factors limit the emission efficiency of LEDs. Here, firstly, through composition and phase engineering, optimal quasi-two-dimensional perovskites are selected. Secondly, surface passivation is carried out by coating organic small molecule trioctylphosphine oxide on the perovskite thin film surface. Accordingly, green LEDs based on quasi-two-dimensional perovskite reach a current efficiency of 62.4 cd A −1 and external quantum efficiency of 14.36%. Solution-processable halide perovskites have high luminous efficiency and excellent chemical tunability, making them ideal candidates for light-emitting diodes. Here Yang et al. achieve high external quantum efficiency of 14% in the devices by fine-tuning the phase and passivating the surface defects.

Simultaneously achieving both a high efficiency and long lifetime in deep-blue organic light-emitting diodes is challenging. Here we report thermally activated delayed fluorescence (TADF) organic light-emitting diodes that aim to meet this goal by combining a new design of blue TADF materials with a triplet-exciton recycling protocol. Two TADF materials, one distributing and one emitting, were doped into a host to form triplet-exciton-distributed TADF devices. The singlet excitons were transferred from the host to the emitter via the distributing TADF material by cascade energy transfer, whereas the triplet excitons were transferred to the emitter as singlet excitons by a triplet-exciton recycling process between the low-triplet-energy host and the distributing TADF material. The resulting triplet-exciton-distributed TADF devices achieved a high external quantum efficiency of 33.5 ± 0.1, a colour coordinate corrected current efficiency over 400 cd A–1, a lifetime of >5,000 h and a y colour coordinate below 0.10.Exciton energy cascade transfer and recycling bring improvements in the efficiency and lifetime of deep-blue organic light-emitting diodes.

Although much effort has been devoted to improving photoelectrochemical water splitting of hematite (α-Fe 2 O 3 ) due to its high theoretical solar-to-hydrogen conversion efficiency of 15.5%, the low applied bias photon-to-current efficiency remains a huge challenge for practical applications. Herein, we introduce single platinum atom sites coordination with oxygen atom (Pt-O/Pt-O-Fe) sites into single crystalline α-Fe 2 O 3 nanoflakes photoanodes (SAs Pt:Fe 2 O 3 -Ov). The single-atom Pt doping of α-Fe 2 O 3 can induce few electron trapping sites, enhance carrier separation capability, and boost charge transfer lifetime in the bulk structure as well as improve charge carrier injection efficiency at the semiconductor/electrolyte interface. Further introduction of surface oxygen vacancies can suppress charge carrier recombination and promote surface reaction kinetics, especially at low potential. Accordingly, the optimum SAs Pt:Fe 2 O 3 -Ov photoanode exhibits the photoelectrochemical performance of 3.65 and 5.30 mA cm −2 at 1.23 and 1.5 V RHE , respectively, with an applied bias photon-to-current efficiency of 0.68% for the hematite-based photoanodes. This study opens an avenue for designing highly efficient atomic-level engineering on single crystalline semiconductors for feasible photoelectrochemical applications. The achievable photocurrent of hematite, α-Fe 2 O 3 , is typically limited far below its theoretical limit. Here, the authors engineer single Pt atomic sites with surface oxygen vacancies into hematite photoanodes, which leads to enhanced photoelectrochemical water splitting.