High Performance Stability Research Articles

Ligand‐Solvent Coordination Enables Comprehensive Trap Passivation for Efficient Near‐Infrared Quantum Dot Light‐Emitting Diodes

AbstractNear‐infrared light‐emitting diodes (NIR LEDs) based on perovskite quantum dots (QDs) have produced external quantum efficiency (EQE) of ~15 %. However, these high‐performance NIR‐QLEDs suffer from immediate carrier quenching because of the accumulation of migratable ions at the surface of the QDs. These uncoordinated ions and carriers—if not bound to the nanocrystal surface—serve as centers for exciton quenching and device degradation. In this work, we overcome this issue and fabricate high‐performance NIR QLEDs by devising a ligand anchoring strategy, which entails dissolving the strong‐binding ligand (Guanidine Hydroiodide, GAI) in the mediate‐polar solvent. By employing the dye‐sensitized device structure (phosphorescent indicator), we demonstrate the elimination of the interface defects. The treated QDs films exhibit an exciton binding energy of 117 meV: this represents a 1.5‐fold increase compared to that of the control (74 meV). We report, as a result, the NIR QLEDs with an EQE of 21 % which is a record among NIR perovskite QLEDs. These QLEDs also exhibit a 7‐fold higher operational stability than that of the best previously reported NIR QLEDs. Furthermore, we demonstrate that the QDs are compatible with large‐area QLEDs: we showcase 900 mm2 QLEDs with EQE approaching 20 %.

Dimeric Small Molecule Acceptors via Terminal-End Connections: Effect of Flexible Linker Length on Photovoltaic Performance.

The dimerization of small molecule acceptors (SMAs) holds significant potential by combining the advantages of both SMAs and polymer acceptors in realizing high power conversion efficiency (PCE) and operational stability in organic solar cells (OSCs). However, advancements in the selection and innovation of dimeric linkers are still challenging in enhancing their performance. In this study, three new dimeric acceptors, namely DY-Ar-4, DY-Ar-5, and DY-Ar-6 are synthesized, by linking two Y-series SMA subunits via an "end-to-end" strategy using flexible spacers (octyl, decyl, and dodecyl, respectively). The influence of spacer lengths on device performance is systematically investigated. The results indicate that DY-Ar-5 exhibits more compact and ordered packing, leading to an optimal morphology. OSCs based on PM6: DY-Ar-5 achieves a maximum PCE of 15.76%, attributes to enhance and balance carrier mobility, and reduce carrier recombination. This dimerization strategy using suitable non-conjugated linking units provides a rational principle for designing high-performance non-fullerene acceptors.

Flexible and air-stable n-type oleylamine/carbon nanotube hybrid yarns for high-performance wearable thermoelectric generators

Wearable thermoelectric generators (TEGs), envisioned to harness the temperature gradient (ΔT) between the human body and the environment into electricity, hold great promise for powering wearable electronics. However, their practical application has been hampered by the scarcity of flexible n-type thermoelectric (TE) materials boasting both high performance and long-term air stability. Here, we introduce a significant advancement by developing an n-type TE material through immersing carbon nanotube yarn (CNTY) into an oleylamine (OAm)/ethanol solution, followed by drying under atmospheric conditions. The resulting OAm/CNTY exhibits a Seebeck coefficient of -80.48 μV K-1, an electrical conductivity of 1353.18 S cm-1 and a power factor of 876.25 μW m-1 K-2, all while exhibiting exceptional mechanical flexibility. Notably, this hybrid yarn maintains stable n-type behavior even after enduring exposure to air for over 370 days, surpassing previous n-type TE materials based on CNT fibers and CNTY. Leveraging this advancement, we construct a prototype wearable TEG by alternately embroidering pristine p-type CNTY and n-type OAm/CNTY into a polyester spacer fabric, electrically connecting them in series using conductive silver paint. The resulting wearable TEG, featuring with 150 p-n couples, yields an output voltage of 705.94 mV and a maximum output power of 44.34 μW at a ΔT of 40 K. This groundbreaking work opens new avenues for the development of high-performance, air-stable, and flexible n-type TE material, ushering in a new era for wearable TEGs.

Chitosan-amidated lignin aerogel beads efficiently loaded with lanthanum hydroxide for phosphate removal from aqueous solutions

Developing phosphorus removal adsorbents with high adsorption performance and excellent structural stability remains a challenge. Herein, a chitosan (CS) - amidated lignin (AL) gel-bead adsorbent with high efficiency in immobilizing lanthanum hydroxide (La(OH)3) was fabricated via an in situ precipitation and freeze-drying strategy (abbreviated as La@ALCSx). The abundant hydroxyl and amino groups in CS promoted excellent loading of La(OH)3 on the surface and inside of the adsorbent. The introduction of lignin enhanced the structural stability of the beads along with the mass transfer efficiency. Owing to the porous structure and high La utilization, the adsorption capacity of La@ALCS2 reached 130.52 mg P g−1. Intra-sphere complexation of La(OH)3 with phosphate resulted in high adsorption selectivity of La@ALCS2. Moreover, the millimeter-sized of La@ALCS2 has favourable recoverability and maintains high adsorption performance after five adsorption-desorption cycles. Characterization analysis indicated that electrostatic attraction and ligand exchange were the main adsorption mechanisms. The excellent phosphorus removal efficiency, separation efficiency and recyclability of La@ALCSx provide a viable solution for the remediation of phosphate contaminated waters.

Efficient recovery of lithium from shale gas wastewater: Fe, Ni, and Al doping of H1.33Mn1.67O4 for improved adsorption capacity and manganese loss reduction

To minimize manganese loss during acid leaching and to enhance the lithium adsorption capacity from shale gas wastewater of H1.33Mn1.67O4, this adsorbent material was doped with metallic elements in this study. Doping was achieved using solid-phase synthesis, resulting first in a Li1.33RXMn1.67−XO4 (R = Fe, Ni, Al) precursor powder through high-temperature calcination. Then, lithium was leached out under acidic environment to obtain the desired H1.33RXMn1.67−XO4 (HMO-R) adsorbents. The equilibrium adsorption capacities of HMO-R powders were measured as 20.7 mg/g, 20.7 mg/g, and 29.0 mg/g, for Fe, Ni, and Al dopants, respectively, surpassing that of the former H1.33Mn1.67O4 (13.7 mg/L). Moreover, an average reduction of manganese loss by 30% for HMO-R was observed during lithium recovery/extraction cycles by acid leaching compared to undoped Li1.33Mn1.67O4. Overall, the doped adsorbent exhibited a stable crystal structure and high adsorption capacity, enhanced stability, performance, and efficiency in cycling experiments with respect to the undoped material.

High-performance single crystal Ni-rich cathode with regulated lattice and interface constructed by separated lithiation and crystallization calcination

Incorporating high valence dopants, such as W6+ and Mo6+ has been verified to be effective for tuning the microstructure and grain boundary of polycrystal Ni-rich cathode. However, the hindered consolidation of primary particles induced by dopants during lithiation calcination limits the utilization of those dopants to crystalize single-crystal Ni-rich cathodes with stabilized lattice and surface. Herein, high performance single crystal LiNi0.84Co0.11Mn0.05O2 cathode with Al3+ and W6+ regulated lattice and boundary phase was construed based on commercial process with two-step calcination process containing separated lithiation and crystallization. The introduction of appropriate amount of Al3+ in the first lithiation calcination of 6 h endows the bulk of crystalline with enhanced lattice stability, while the incorporation of W6+ with stoichiometrical LiOH in the secondary crystallization calcination of 6 h renders uniformly distributed surface layer without hampering the growth of single-crystal. With the Al3+ doped bulk lattice, W6+ doped subsurface region and hetero-epitaxially grown Li2WO4, the cathode infused by two-step calcination exhibits high discharge capacity, rate performance, and cycling stability. Specifically, the modified LiNi0.84Co0.11Mn0.05O2 exhibits exceptional capacity retention, maintaining 88.98% of its initial capacity after 200 cycles at a rate of 1 C within a voltage window of 2.7–4.3 V at a temperature of 25 °C in half-cell. This performance is markedly superior to the capacity retention of 72.96% observed for pristine cathode. Even when subjected to a stringent test after 200 cycles at the same rate, the modified cathode sustains an impressive capacity retention of 82.41% at an elevated cut-off voltage of 4.5 V and a temperature of 30 °C.

A Universal Biocompatible and Multifunctional Solid Electrolyte in p-Type and n-Type Organic Electrochemical Transistors for Complementary Circuits and Bioelectronic Interfaces.

The development of soft and flexible devices for collection of bioelectrical signals is gaining momentum for wearable and implantable applications. Among these devices, organic electrochemical transistors (OECTs) stand out due to their low operating voltage and large signal amplification capable of transducing weak biological signals. While liquid electrolytes have demonstrated efficacy in OECTs, they limit its operating temperature and pose challenges for electronic packaging due to potential leakage. Conversely, solid electrolytes offer advantages such as mechanical flexibility, robustness against environmental factors, and ability to bridge the interface between rigid dry electronics systems and soft wet biological tissues. However, few systems have demonstrated generality and compatibility with a wide range of state-of-the-art organic mixed ionic-electronic conductors (OMIECs). This paper introduces a highly stretchable, flexible, biocompatible, self-healable gelatin-based solid-state electrolyte, compatible with both p- and n-type OMIEC channels while maintaining high performance and excellent stability. Furthermore, this nonvolatile electrolyte is stable up to 120°C and exhibits high ionic conductivity even in dry environment. Additionally, an OECT-based complementary inverter with a record-high normalized-gain of 228 V-1 and a corresponding ultralow static power consumption of 1 nW is demonstrated. These advancements pave the way for versatile applications ranging from bioelectronics to power-efficient implants.

Универсальная централизованная защита от однофазных замыканий на землю в кабельных сетях напряжением 6–10 кВ

Selective protection against single phase earth faults in distribution 6–10 kV cable networks can be performed both with the use of individual (per connection) and centralized devices covering all connections of the protected object. The advantages of centralized devices are reduction of specific (per connection) costs of protection, simplification of its operation and design. Well-known technical solutions in terms of centralized protection devices against this type of damage do not always provide versatility (the possibility to use neutral cables of 6–10 kV in various grounding modes) and high technical perfection (selectivity and stability of operation). Thus, it is relevant to develop a universal centralized protection against single-phase earth faults, ensuring high technical perfection for all types of earth faults in 6–10 kV cable networks with different neutral grounding modes. The authors have used a comprehensive simulation model "cable network – protection device" to study the selectivity and stability of the developed principles of implementation and algorithms for centralized protection against earth faults. The model is designed in SimPowerSystems and Simulink software. The configuration and parameters of the cable network model have been selected considering the key features of 6–10 kV distribution cable networks of industrial and urban power supply systems. A universal centralized protection against all types of earth faults in 6–10 kV cable networks with various neutral grounding modes has been developed. The results of functional tests on the simulation model have confirmed the effectiveness of the developed algorithms of the developed centralized protection for all types of earth faults both in uncompensated and compensated cable networks of 6–10 kV. The proposed technical solution implements a multifunctional multiparametric centralized protection against earth faults. It has such properties as versatility, selectivity, and high stability of operation for all types of earth faults, recognition of types of single-phase earth faults, continuity of action in stable and most dangerous arc intermittent earth faults.

Effect of metal cation coaddition in phosphovanadomolybdate anion catholytes on the redox flow polymer electrolyte fuel cell performance

Redox flow polymer electrolyte fuel cells (RFFCs) employing heteropolyanions (HPAs) as cathode redox mediators enable continuous power generation through the electrochemical reduction of the HPAs at the carbon cathode and subsequent reoxidation of the reduced-form HPAs in the cathode tank. Currently, effective reoxidation methods are required to achieve both high performance and long-term stability. Heteropolyanions such as α–[PW12O40]3– and α–[SiVW11O40]5– have increased reoxidation rates in the presence of radical species. In this study, fuel cell performance is investigated by adding Fe3+ and Cu2+ to the aqueous solution of [PV3Mo9O40]6–, which is used as a catholyte in RFFCs to increase the concentration of radicals in the system. Current–voltage measurements show that the added metal cations in the catholyte increase the power density. A temporary improvement in cell performance is observed during a prolonged current passage test.

Van der Waals interactions enhanced multiple-times all-waste-recycled triboelectric nanogenerator for ultra-high lifetime stability

To mitigate the ever-increasing waste problem, utilization of recycled waste to fabricate energy harvesting devices has emerged as a propitious alternative. Despite several efforts, it is still a daunting challenge to sustain the properties of recycled-plastic-waste after multiple rounds of recycling. We address the above challenges by developing an industry-viable universal framework to recycle plastic-waste multiple-times without significant degradation in its properties. A multiple-times all-recycled triboelectric nanogenerator (MR-TENG) was demonstrated with high performance and record-high overall operational lifetime stability for 5 million cycles of mechanical impact. To the best of our knowledge, this is the first report of a nanogenerator made completely from recycled mixed-plastic-waste, which can sustain its energy-harvesting performance even after ten rounds of recycling. The multiple-times recyclability can be attributed to the improved van der Waals interactions between the polymeric blends at the macromolecular level facilitated by incorporating a mixed-plastic waste-derived compatibilizing agent, which is validated by molecular dynamics simulation. The adopted industry-viable reactive extrusion to fabricate the materials facilitates easy adaptability and commercialization. The practical application was demonstrated by utilizing it for deep learning-enabled MR-TENG-based advanced cognitive waste sorting and segregation, facilitating digitalized-waste-management, thus facilitating a major step towards upcycling of plastic-waste for circular economy.

Comprehensive Review of Li-Rich Mn-Based Layered Oxide Cathode Materials for Lithium-Ion Batteries: Theories, Challenges, Strategies and Perspectives.

Lithium-rich manganese-based layered oxide cathode materials (LLOs) have always been considered as the most promising cathode materials for achieving high energy density lithium-ion batteries (LIBs). However, in practical applications, LLOs often face some key problems, such as low initial coulombic efficiency, capacity/voltage decay, poor rate performance and poor cycle stability. It seriously shortens the lifespan of lithium-ion batteries and hinder the large-scale commercial application of LLOs. Herein, firstly, the basic theories of LLOs were systematically reviewed, including the structural characteristics, the working mechanism of LLOs, the preparation methods of LLOs (liquid phase co-precipitate method, sol-gel method, hydrothermal synthesis method, solid phase method, low heat solid-phase method, high temperature solid-state method etc.), and electrochemical characteristics of LLOs (first charge discharge characteristics and reversible efficiency, cycling performance, high and low temperature performance and thermal stability etc.). Then, key challenges faced by LLOs were systematically discussed. Finally, the LLOs modification strategies used to address these challenges (element doping, surface modification, defect engineering, structural and morphological control etc.) were elaborated in detail. This important review provides potential insights and directions for further improving the electrochemical performance of LLOs, and provides a necessary theoretical basis for accelerating the large-scale commercial application of LLOs. It possesses important scientific research value and far-reaching social significance.

In Situ Growth of Gold Nanofilms with Branched Structures in the Presence of Organosulfur for High-Performance Flexible Electronics.

Herein, a novel method is presented for the in situ growth of gold nanofilms with branched structures in the presence of organosulfur. The key feature in this approach is the Rayleigh instability of ultrathin gold nanowires (AuNWs) without oleylamine (OAm), which allows the ultrathin AuNWs to decompose into gold nanoparticles (AuNPs) and the AuNPs to in situ grow into branched structures for high-performance stability and electrical conductivity. The sheet resistance of the gold nanofilms initially sharply decreased, whereas it subsequently slightly increased with the concentration of CS(NH2)2 until it exceeded the optimal range. After undergoing a 10 min heat treatment at 150 °C, the sheet resistance of the nanofilms was further reduced to 18 Ω/sq, which could be maintained for more than five months. The internal structure becomes fully grown and denser, forming a branched structure after heat treatment. Only certain organosulfurs can improve the electrical properties of the gold nanofilms, and the mechanism of organosulfur in the in situ growth of gold nanofilms with branched structures has also been presented. Overall, this novel method provides a straightforward and convenient approach to obtaining gold nanomaterials with branched structures, holding great potential promise for applications in flexible electronics, catalysis, and energy fields.

A study on misfire detection by calculating crank angular velocity considering in-cylinder gas properties

Misfire detection using a new crank angular velocity calculation was studied for high efficiency and robust engine ignition performance and combustion stability control. An applying production was achieved by applying in-cylinder gas properties prediction and its correction to the misfire index and verifying it under various conditions. The relationship between the misfire index and torque fluctuation was consistent depending on the combustion control factors EGR, injection timing, pilot injection quantity change, and environmental change factors water temperature and intake gas temperature. On the other hand, it was found that the piston speed changes due to the in-cylinder pressure with respect to the intake pressure, and the crank angular speed needs to be corrected. Commonly used sensors for engine cooling water temperature, intake gas temperature, intake pressure, and engine speed were used as representative values for in-cylinder pressure, and the cooling loss was subtracted from the polytropic index and the reduction in specific heat ratio due to EGR was corrected. By building a new model that calculates the compression end pressure model from the polytropic index and adding corrections to the misfire index, we applied logic that can be calculated for each cycle to the ECU onboard. Conventionally, compression end pressure prediction requires calculations that take combustion conditions into account, which requires the number of sensors and their accuracy, and a long calculation time. However, in this study, Authors focused on the fact that the pressure at TDC during a misfire does not include ignition and combustion phenomena and expressed the necessary physical phenomena using the minimum sensor information. As a result of the above, a control structure at a level that can be applied to products was obtained.

Soft and diffusion-controlled Sr-MOF for efficient separation of H2O/D2O

Heavy water (D2O) electrolysis is the primary technology for D2 production, playing an irreplaceable role in fields such as nuclear fusion research and isotope tracing. However, the inherent similarity in chemical properties between H2O and D2O (with only a 1.4 °C difference in boiling points) poses significant challenges to their separation. Furthermore, the extremely low natural abundance of D2O (0.015 %) increases the difficulty and cost of separation, while traditional electrolysis and distillation techniques are highly energy intensive. Therefore, there is an urgent need to develop novel adsorbents for efficient and environmentally sustainable H2O/D2O separation. Herein, we used polydentate ligand 2, 5-dihydroxyterephthalic acid (DOBDC) and its derivatives 4,4́-(anthracene-9,10-diyl) bis (2-hydroxybenzoic acid (ABHB) as raw materials to prepare two novel high coordination Sr-MOFs namely IPE-1 and IPE-2, respectively. These MOFs were applied for efficient separation of H2O and D2O at room temperature. X-ray diffraction results reveal that one Sr atom in IPE-1 is coordinated with 9 oxygen atoms. This high coordination number results in the formation of ultra-small rectangular pores of approximately 2.5 Å. Adsorption isotherms of N2, CO2, H2O, and D2O indicate that the ultramicroporous structure of IPE-1 precludes efficient diffusion of CO2 and H2O molecules into the MOF channels. In contrast, the activated IPE-2 exhibits good CO2, H2O, and D2O uptake capacities of 3 mmol/g, 8.38 mmol/g, and 6.51 mmol/g at 298 K, respectively. The Qst values and Ksap values of H2O and D2O indicate that the adsorption rates of H2O were much higher than D2O under 0.2 < P/P0 < 0.7, with a calculated ratio of approximately 1.26. This study not only provides appealing MOFs materials for efficient H2O/D2O separation at room temperature but also provides a new avenue for preparing adsorbents with high stability and high separation performance.

(Digital Presentation) Integrated Membrane Electrode Assembly in Proton Exchange Membrane Fuel Cells

Proton exchange membrane fuel cells (PEMFCs), an electrical device with high energy conversion efficiency and zero-carbon emission, has attracted more attention. The membrane electrode assembly (MEA) is the core component of PEMFCs, mainly including proton exchange membrane (PEM), catalyst layer (CL), microporous layer (MPL) and carbon fiber gas diffusion layer (GDL), which has different structures and significantly affects its power density and durability [1].Generally, MEA is fabricated by catalyst coated electrodes (CCE) and catalyst coated membrane (CCM) methods, which often results in a huge interface resistance between electrode and membrane, the weak adhesion and poor proton and electron transfer, limiting the electrochemical surface area (ECSA) and the power density of PEMFCs [2].To solve this problem, many approaches have been adopted, such as improving sintering temperature for MEA, incorporating a guided cracked layer between cathode and membrane, double-layered catalyst and direct deposition method. Zhao et al prepared an integrated membrane electrode assembly structure to reduce the contact resistance between proton exchange membrane and catalyst layer, which significantly improves the efficiency and stability of water electrolysis [4]. At the same time, Klingele and Breitwieser developed a direct deposition of proton exchange membrane technology to improve high performance and long-term stability of PEMFCs. However, these methods are complex and almost impossible to industrialize [5].In this study, integrated membrane electrode assembly (I-MEA) was prepared by combining casting and doctor blade method techniques. The results show that the casting method is more suitable for fabricating I-MEALT in low-temperature proton exchange membrane fuel cells. The power density of the I-MEALT cell is increased by 18% compared with that of the conventional MEALT (Fig. 1). The doctor blade method is more suitable for preparing I-MEAHT in high-temperature proton exchange membrane fuel cells. The maximum power density of I-MEAHT is increased by about 57% compared with that of the conventional MEAHT. The electrochemical impedance shows that this is mainly attributed to the reduced interface resistance between the electrode and the membrane, which facilitates the proton transfer.

Realizing high thermoelectric performance and thermal stability in CuInTe2 through heavy dose Mg doping

Cu based ternary compounds have received intensive attentions as thermoelectric materials but their carrier mobility and thermal stability are subject to native Cu vacancy. In this work, the synergistic improvement in thermoelectric performance and stability in CuInTe2 is presented, facilitated by local chemical bond enhancement. Heavy dose Mg doping on In site can successfully suppress the formation of Cu vacancy in CuInTe2 and its thermal stability is significantly improved. As a result, In comparison to alternative dopants, Mg doping demonstrates a notable capacity for reinforcing the lattice structure through the inhibition of copper vacancies, thereby yielding a considerable enhancement in mobility by 20 %∼50 %, and the zT value of CuIn0.94Mg0.06Te2 exceeds 1.2 at 873 K. By further alloying with Ga on In site, the thermal conductivity is greatly reduced and more surprisingly the thermal stability is continuously enhanced. Notably, in Cu(In0.4Ga0.6)0.94Mg0.06Te2, a peak zT value of 1.72 at 973 K is achieved, while in Cu(In0.6Ga0.4)0.94Mg0.06Te2, an average zT value of 0.82 is attained. This study offers valuable insights into optimizing the thermoelectric performance and thermal stability of Cu-based ternary compounds through effective doping and defect regulation, providing guidance for future research in this field.

Polyfunctional Arylamine Based Nanofiltration Membranes with Enhanced Aggressive Organic Solvents Resistance.

Organic solvent nanofiltration (OSN) membranes with high separation performance and excellent stability in aggressive organic solvents are urgently desired for chemical separation. Herein, we utilized a polyfunctional arylamine tetra-(4-aminophenyl) ethylene (TAPE) to prepare a highly cross-linked polyamide membrane with a low molecular weight cut-off (MWCO) of 312 Da. Owing to its propeller-like conformation, TAPE formed micropores within the polyamide membrane and provided fast solvent transport channels. Importantly, the rigid conjugated skeleton and high connectivity between micropores effectively prevented the expansion of the polyamide matrix in aggressive organic solvents. The membrane maintained high separation performance even immersed in N,N-dimethylformamide for 90 days. Based on the aggregation-induced emission (AIE) effect of TAPE, the formation of polyamide membrane can be visually monitored by fluorescence imaging technology, which achieved visual guidance for membrane fabrication. This work provides a vital foundation for utilizing polyfunctional monomers in the interfacial polymerization reaction to prepare high-performance OSN membranes.

Mechanical and microstructure characterisation of 2.5D C/C-SiC composites applied for the brake disc of high-speed train

Carbon fibre reinforced silicon carbide (C/C-SiC) composite materials have attracted increasing attention in brake system of high-speed trains, due to their low density, high specific strength, thermal stability, and frictional wear performance. This study aims to explore the mechanical properties of the 2.5D C/C-SiC composites, in order to characterise its potential application to the friction braking system of high-speed trains. To comprehensively evaluate the mechanical performance of the 2.5D C/C-SiC composites, the chemical vapor infiltration (CVI) method was adopted to prepare novel samples with high densification and low content of residual Si. The mechanical properties and failure mechanisms of the composites were investigated under various loading conditions, including tension, compression, bending, and shear tests. The experimental results indicated that the 2.5D C/C-SiC composites exhibited superior mechanical properties, with average in-plane tensile strength, compressive strength, bending strength, and interlaminar shear strength reaching 127.67 MPa, 326.92 MPa, 355.74 MPa, and 9.77 MPa, respectively, which are 2–8 times higher than the mechanical properties of C/C-SiC composites in existing publications. Under different loading conditions, the composites demonstrated characteristics of ductile fracture, pseudo-plastic compression fracture, pseudo-plastic bending fracture, and brittle shear fracture. Both high fibre content and the formation of SiC structure were advantageous for enhancing the load-bearing performance of C/C-SiC composites. The outstanding mechanical properties of the 2.5D C/C-SiC composite render the brake disc highly resistant to deformation and cracking under high stress, thereby enhancing its durability and establishing it as the ideal material for the next generation of high-speed train brake discs.

Stable and efficient all-inorganic quantum dot light-emitting diodes based on a double-layer electron transport layer

Abstract The most advanced quantum light-emitting diodes (QLEDs) have achieved almost unity external quantum efficiency (EQE) due to organic materials for high transport efficiency, but organic materials are less stable and can lead to irreversible degradation of the devices. The use of stable inorganic hole-transporting layers (HTLs), such as NiOx, becomes a promising alternative. ZnO is a common electron-transporting material in QLEDs, which possesses high mobility and tunable conductivity properties, but ZnO-based QLEDs devices undergo loss of efficiency due to exciton bursting, poor shelf stability, and pronounced positive aging effects. SnO2, as a common electron-transporting material, has better stability than ZnO. In this work, the SnO2/ZnO dual electron transport layer strategy is adopted, which can reduce the non-radiative burst and aging behavior, and at the same time, the electron transport is regulated by adjusting the film thickness. Inorganic QLEDs with high external quantum efficiency (9.5%) as well as high operational stability have been fully realized. This strategy provides effective ideas for future high-performance display devices.

New hole transport materials based on polybenzo[1,2-b:4,5-b']dithiophene polymers with different side chains for n-i-p perovskite solar cells

A series of new homo- and copolymers P1–P6 with the main chains comprised exclusively of benzo [1,2-b:4,5-b']dithiophene units were synthesized using Stille polycondensation reaction. The optical and electrochemical properties of P1–P6 polymers were studied to estimate the frontier orbitals energies and the Eg values. The obtained data demonstrate the possibility of controlling the electronic properties of polybenzo [1,2-b:4,5-b']dithiophenes by varying only the structure and combinations of solubilizing alkyl side chains. The polymers P1–P6 were evaluated as hole transport materials in n-i-p perovskite solar cells. The highest efficiency of 18.6 % was delivered by the cells with one of the designed polymers with an optimal combination of alternating mono- and dialkylthiophene substituents. The high photovoltaic performance and decent operational stability were achieved using polymer films without any doping, which paves a way to design of inexpensive and scalable dopant-free materials for perovskite solar cells.