Interlayer Material Research Articles

Effects of interlayer on the friction stir spot welding of stainless steel

Comparison of Interlayer Friction Stir Spot Welding (IL-FSSW) and conventional Friction Stir Spot Welding (FSSW) of 304 stainless steel is presented in this study. IL-FSSW is introduced as a novel spot-welding technique to avoid the keyhole formation at the weld spot. This process is employed to fabricate a joint between two stainless steel sheets. The utilization of an interlayer material prevents the occurrence of keyhole without any additional post-process treatment. In addition, the interlayer material also enhances ductility and provides a joint with a maximum lap shear load of 7 kN. The micrographs of the weld zone cross-section were recorded and it was observed that the interlayer material played a significant role in the development of the nugget zone by supporting the formation of a hook structure.

Recent advances in thin film nanocomposite membranes containing an interlayer (TFNi): fabrication, applications, characterization and perspectives.

Polyamide (PA) reverse osmosis and nanofiltration membranes have been applied widely for desalination and wastewater reuse in the last 5-10 years. A novel thin-film nanocomposite (TFN) membrane featuring a nanomaterial interlayer (TFNi) has emerged in recent years and attracted the attention of researchers. The novel TFNi membranes are prepared from different nanomaterials and with different loading methods. The choices of intercalated nanomaterials, substrate layers and loading methods are based on the object to be treated. The introduction of nanostructured interlayers improves the formation of the PA separation layer and provides ultrafast water molecule transport channels. In this manner, the TFNi membrane mitigates the trade-off between permeability and selectivity reported for polyamide composite membranes. In addition, TFNi membranes enhance the removal of metal ions and organics and the recovery of organic solvents during nanofiltration and reverse osmosis, which is critical for environmental ecology and industrial applications. This review provides statistics and analyzes the developments in TFNi membranes over the last 5-10 years. The latest research results are reviewed, including the selection of the substrate and interlayer materials, preparation methods, specific application areas and more advanced characterization methods. Mechanistic aspects are analyzed to encourage future research, and potential mechanisms for industrialization are discussed.

Effects of interlayer metal on microstructures and mechanical properties of friction stir lap welded dissimilar joints of magnesium and aluminum alloys

The content of intermetallic compounds (IMCs) in friction stir lap welded (FSLW) dissimilar joints of Mg and Al alloys could be reduced by the addition of interlayer metal to improve the mechanical properties of the joints, while the underlying mechanism is still unclear. In this study, Cu and Ni powders are added as the interlayer materials into the FSLW joints of AZ31 Mg alloy and Al–Zn–Cu–Mg alloy, respectively. The types, sizes, and distributions of IMCs have been characterized, and the shear properties of the joints have been evaluated. Moreover, the mechanism underlying the influence of the interlayer metals on the evolution of IMCs in the joints and the effect of IMCs on the shear properties of the joints have been studied. The results showed that the order of phase formation in the joint without interlayer was Al12Mg17, Al3Mg2, MgZn2, CuMg2, Al2Cu, while the order of phase formation in the joint with added Cu interlayer was Al2Cu, CuMg2, AlCu, Al12Mg17, Al3Mg2, Cu5Zn8, and that in the joint with added Ni interlayer was Mg2Ni, Al3Ni, Al3Ni2, MgNi2, AlNi, Al12Mg17, Al3Mg2, MgZn2, Ni3Zn22, NiZn, Al2Cu. Due to the formed physical barrier and the mechanism of phase formation, the addition of interlayer metal effectively inhibited the formation of a Mg–Al phase. The bonding strengths between Mg–Cu, Al–Cu, Al–Ni, and Mg–Ni phases and matrix were higher than that between Mg–Al phase and matrix, which improved the shear properties of the joints with Cu and Ni interlayers.

Organic–inorganic hybrid cathode interlayer materials for efficient organic solar cells

Organic–inorganic hybrid cathode interlayer materials in OSCs, which can not only lead to higher device efficiency and enhanced stability but also provide correlation between composition/structure and device performance, are summarized.

Water‐Soluble Organic Dyes as Efficient Anode Interlayer Materials for PEDOT:PSS‐Free Inverted Bulk Heterojunction Solar Cells

Solution‐processed inverted organic solar cells (OSCs) generally use poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate (PEDOT:PSS) as hole selective anode interlayer (AIL). However, the acidic nature of PEDOT:PSS considerably accelerates the degradation dynamics of OSCs, which shortens the durability of these low‐cost photovoltaic devices. Small organic molecules are attracting growing interest as alternative AIL materials, but their solubility limited to toxic organic solvents hinders the production of environmentally friendly OSCs. Herein, the first inverted OSCs employing non‐PEDOT:PSS solution‐processed top small organic molecule AILs deposited from aqueous solution are reported. The investigated water‐soluble spirobifluorene (SBF) derivatives 1 and 2 show hole mobility (≈4 × 10−3 cm2 V−1 S−1) higher than PEDOT:PSS. Because of their nonacidic nature, the interlayers formed with derivatives 1 or 2 considerably delay the degradation of the top metal electrode compared to OSCs employing PEDOT:PSS interlayers. The PEDOT:PSS‐free OSC devices with inverted configuration with the water‐soluble SBF derivatives as AIL produce power conversion efficiencies above 5% with PTB7‐Th:ITIC active layers and above 8% with PBDB‐T‐2Cl:Y6 active layers, respectively, with an enhancement up to 28% compared to OSCs employing PEDOT:PSS. These results correspond to the highest reported values for PEDOT:PSS‐free small‐molecule inverted OSCs deposited from an aqueous solution.

Process Review on Dissimilar Metal Joining of Steel and Ti Alloys

Titanium alloys have high specific strength and excellent high-temperature properties. However, Ti alloys have limited weldability with other metals due to the formation of brittle intermetallic compounds. Moreover, when steel is a counterpart of dissimilar metal joining, the soundness of weld is hardly achieved due to weld defects. Numerous studies have been conducted to achieve joint strength by minimizing the effects of Fe-Ti intermetallic compounds. In most studies, pure titanium or Ti-6Al-4V alloy were selected as the Ti base metal, whereas stainless steel, low carbon steel, or alloy steel were selected as the steel base metal. To date, joining processes such as diffusion bonding, brazing, fusion welding, and solid-state joining have been investigated. In this study, the characteristics of each of these joining processes were reviewed. More specifically, the formation of intermetallic compounds was analyzed when Ti alloy and steel were directly joined without using interlayer materials.

Designing of interlayers between materials with minimum stress level at the interface

The stress concentration at the interface between two dissimilar materials is a serious problem in designing adhesive joints and composite structures. Numerous studies have been conducted with the aim of reducing the stress concentration at the interface between dissimilar materials. In most of these works it was achieved by changing the geometry or properties of one of the materials at the edges of the interface. In this paper we propose a method of determining the values of elastic constants of the interlayer material and its geometry near the edges of the interfaces, to reduce the stress concentration. The method is based on the results of solving the problem of stress optimisation in the vicinity of singular points, according to which the optimal variants determine the boundary between the solutions with and without stress singularity. The paper presents the results of the construction of eigensolutions in the vicinity of singular points, which allow us to determine the ranges of parameters responsible for the appearance of solutions with and without stress singularity. The main advantage of the proposed method is the possibility of finding the range of optimal configurations for the interlayer, which is made of homogeneous or functionally graded material and used to bond materials having similar or dissimilar properties. A number of model problems are solved to demonstrate the capabilities of the proposed method in a search for the optimal mechanical characteristics of the elastic interlayer between two similar or dissimilar materials and its geometric parameters, in order to minimise the stress concentration at their interface.

Exploring Inorganic Hole Collection Materials from Mixed‐Metal Dawson‐Type Polyoxometalates for Efficient Organic Photovoltaic Devices

Interfacial layer materials play an important role in performance enhancement of organic solar cells (OSCs). Herein, the utilization of mixed‐metal Dawson‐type polyoxometalates, namely P2Mo3W15O62 (POM‐1) and P2Mo9W9O62 (POM‐2), as anode interlayer (AIL) materials, for efficiently collecting holes to boost the photovoltaic efficiency of OSCs, is explored. The increase in molybdenum substitution in the mixed‐metal POMs can lower the conduction band level and increase the reduction potential. Meanwhile, the high work function of POMs helps to remove the energy barrier in the hole collection, which solves the serious problem of Voc loss in OSCs. As a result, OSCs modified by POM‐2 can exhibit superior photovoltaic performance with power conversion efficiency of 14.8%. The results of Mott−Schottky analysis, current density−light intensity dependence, and excitons dissociation probability indicate the efficient hole collection and the depressed charge recombination in the POM‐2‐based OSC device. By means of fabricating OSCs, the effect of the two POM‐based AILs on various photoactive layers is also investigated, and POM‐2 exhibits excellent hole collection capability. Moreover, the advantages of low‐cost and solution‐processable conduct make POM‐2 a promising candidate as the AIL material for future mass production of OSCs.

Tensile Characteristics of Mechanical Lap Joints Between Commercial ReBCO Tapes With Various Interlayer Materials

In this work, the mechanical lap joint of commercial ReBCO tape from SHSC is prepared. The tape is reinforced with stainless steel bar in both side to reduce the effect of bending moment in the joint tensile test. We use Indium and GaInSn as interlayer material, respectively, and different pressures are applied on the joint by jig during testing. The relationship between joint resistance and applied tensile stress was measured at 77 K. The results shows that for all measured joints under pressure, the voltage rise duo to tensile stress is small at first and then sharply grows until a certain value of stress is reached. The maximum tensile stress is higher for the joint which has lower resistance. Comparing two types of mechanical lap joints with Indium and GaInSn, the former joint shows smaller dispersion on joint resistance than the latter under pressure above 40 Mpa. It is also shown that the joint with Indium can tolerate higher tensile stress than the joint with GaInSn by using the Weibull distribution function analysis.

Impact of Interlayer and Ferroelectric Materials on Charge Trapping During Endurance Fatigue of FeFET With TiN/Hf x Zr1-x O2/Interlayer/Si (MFIS) Gate Structure

We study the impact of different interlayers (ILs) and ferroelectric materials on charge trapping during the endurance fatigue of Si ferroelectric field effect transistor (FeFET) with TiN/Hf_<i>x</i>Zr_1-<i>x</i>O₂/ interlayer/Si (MFIS) gate-stack. We have fabricated FeFET devices with different interlayers (SiO₂ or SiON) and Hf_<i>x</i>Zr_1-<i>x</i>O₂ materials (<inline-formula> <tex-math notation="LaTeX">${x} =0.75$ </tex-math></inline-formula>, 0.6, 0.5) and directly extracted the charge trapping during endurance fatigue. We find that: 1) under the same equivalent oxide thickness (EOT) condition, the increase of dielectric constant and interlayer thickness suppresses charge trapping and improves the endurance characteristics; 2) charge trapping effect is experimentally verified to be the origin of endurance fatigue; and 3) as the spontaneous polarization (<inline-formula> <tex-math notation="LaTeX">${P}_{\text {s}}{)}$ </tex-math></inline-formula> of the Hf_<i>x</i>Zr_1-<i>x</i>O₂ decreases from <inline-formula> <tex-math notation="LaTeX">$25.9~ \boldsymbol {\mu } \text{C}$ </tex-math></inline-formula>/cm² (Hf_0.5Zr_0.5O₂) to <inline-formula> <tex-math notation="LaTeX">$20.3~ \boldsymbol {\mu } \text{C}$ </tex-math></inline-formula>/cm² (Hf_0.6Zr_0.4O₂), the charge trapping behavior decreases, resulting in the slow degradation rate of memory window (MW) during program/erase cycling; in addition, when <inline-formula> <tex-math notation="LaTeX">${P}_{\text {s}}$ </tex-math></inline-formula> further decreases to <inline-formula> <tex-math notation="LaTeX">$8.1~ \boldsymbol {\mu }\text{C}$ </tex-math></inline-formula>/cm² (Hf_0.75Zr_0.25O₂), the initial MW nearly disappears (only &#x007E;0.02 V). Thus, the reduction of <inline-formula> <tex-math notation="LaTeX">${P}_{\text {s}}$ </tex-math></inline-formula> could improve endurance characteristics. On the contrary, it can also reduce the MW. Our work helps design the MFIS gate-stack to improve endurance characteristics.

Fe-carbon hybrid composite interlayer for improved electrochemical performance of Li-S battery

The major bottlenecks in achieving the full potential of Lithium-sulfur (Li-S) batteries are the insulating nature of sulfur and Li-polysulfide (Li-PS) shuttling which lead to their poor rate performance and cyclic stability. In this work, we solve these critical issues using a unique Fe-carbon hybrid composite interlayer prepared by the catalytic graphitization of resorcinol formaldehyde (RF) xerogel. The physicochemical characterizations of the interlayer material reveal that it consists of iron-nanoparticles encapsulated by graphitic carbon within the amorphous RF xerogel derived hard carbon matrix (Fe-G-HC-IL). The Li-S battery, with Fe-G-HC-IL as a functional separator and activated candle soot-sulfur composite cathode, demonstrates a significantly improved electrochemical performance than without the interlayer. The Li-S battery with Fe-G-HC-IL shows the capacity of 1057 mAh g−1 at 1 C-rate with a decay rate of 0.055% per cycle and excellent rate capability. Further, density functional theory (DFT) calculation indicates that the Fe embedded carbon structure present in interlayer composite contributes significantly to the improvement in the conductivity and minimization of Li-PS shuttling. Additionally, this Fe-carbon hybrid structure electro catalyzes the conversion of Li-PS to desired end products of the redox reactions which further enhance the electrochemical performance of Li–S batteries.

Simultaneous realization of holey in-plane defects and expanded interlayers in N-containing nanocarbons from a non-covalent-bonded organic framework for efficient oxygen reduction reaction

We herein design a non-covalent assembly motif of hydrogen-bonded organic frameworks (HOF), which is experienced by a simple carbonization process to form a novel both expanded interlayer and holey in-plane nitrogen-containing nanocarbon material (EH-NCM). The escaped species in pyrolysis from the element decomposition in the HOF plays an important role in the simultaneous construction of holey defect and expanded interlayer. The potentiostatic intermittent titration experiment shows that oxygen diffusion coefficient in EH-NCM is improved by 1 order of magnitude compared with the commercial Pt/C and the unexpanded NCM. Calculations also show in-plane defects can efficiently bind with O2 and benefit to four-electron oxygen reduction reaction (ORR) process, assisted by the enlarged interlayer distance. The as-prepared EH-NCM delivers ORR activity with half wave potential and onset potential at 0.93 V and 1.05 V respectively, limited current density of 6.1 mA cm−2, and a low Tafel slope of 67 mV dec−1, showing H2O2 yield of less than 4% superior to the commercialized Pt/C. Also EH-NCM-based Zn–air battery displays excellent cathode performances. The accelerated mass transfer and maximum exposure of the active sites resulted from the holey and expanded dual structure of EH-NCM is responsible for the outstanding ORR performances.

Low-Permittivity Copolymerized Polyimides with Fluorene Rigid Conjugated Structure.

As the miniaturization of electronic appliances and microprocessors progresses, low-permittivity interlayer materials are becoming increasingly important for their suppression of electronic crosstalk, signal propagation delay and loss, and so forth. Herein, a kind of copolyimide (CPI) film with a “fluorene” rigid conjugated structure was prepared successfully. By introducing 9,9-Bis(3-fluoro-4-aminophenyl) fluorene as the rigid conjugated structure monomer, a series of CPI films with different molecular weights were fabricated by in situ polymerization, which not only achieved the reduction of permittivity but also maintained excellent thermodynamic stability. Moreover, the hydrophobicity of the CPI film was also improved with the increasing conjugated structure fraction. The lowest permittivity reached 2.53 at 106 Hz, while the thermal decomposition temperature (Td5%) was up to 530 °C, and the tensile strength was ≥ 96 MPa. Thus, the CPI films are potential dielectric materials for microelectronic and insulation applications.

(Invited) Fabrication and Characterization of Ge-Based MIS Structures

Germanium (Ge) is a very attractive channel material for future high-performance metal-insulator-semiconductor (MIS) devices because it exhibits much higher low-field electron (two times higher) and hole (four times higher) mobilities than Si. In addition, the smaller band gap of Ge than that of Si should allow the further reduction of power consumption in advanced integrated circuits and the lower melting point of Ge than that of Si also enables Ge-based device integration at low processing temperatures. However, until the early years of the 2000s, the reported electrical properties of high-k/Ge interfaces had been so poor that one of the critical issues in establishing Ge-based MIS technology was the effective passivation of Ge surfaces by dielectrics with superior interface properties. Although the quality of the Ge-MIS structure has been remarkably improved in the past decade, the relationship between the processing methods and the quality has not been discussed precisely.In this paper, we report on the fabrication of Ge MIS structures with various high-k dielectric materials and interlayer materials through various methods. We also introduce the convenient method to characterize the interface trap densities (Dit's) of the MIS capacitors by spectroscopic measurement of the interface trap density in an insulator/Ge interface at room temperature [1]. The effects of the insertion of interlayers into the interface of high-k insulator/Ge and the application of heat treatment to the Ge MIS structures will be also presented.For instance, the Dit of Ta2O5/GeNx/Ge fabricated by electron-cyclotron-resonance (ECR) plasma nitridation and sputtering was estimated to be 4×1011 cm-2 · eV-1 [2], that of Si3N4/GeNx/Ge by ECR plasma nitridation to be 1×1011 cm-2 · eV-1 [3-6], and that of Al2O3/GeO2/Ge by ECR plasma oxidation and sputtering to be 4.5×1010 cm-2 · eV-1 [7-9]. These results have summarized that the adequate surface preparations of the interfaces and films by the ECR plasma process with low energy plasma irradiation have been effective to realize the low Dit of MIS structures with GeO2 and/or GeNx.These results have expanded to another MIS structures fabricated by more conventional film formation technique such as the atomic layer deposition (ALD) and the radio frequency (RF) magnetron sputtering. The Dit of Al2O3/Al germanate/Ge by ALD with trimethylaluminum (TMA) and microwave-generated atomic oxygen was estimated to be 2×1011cm-2 · eV-1 [10], and that of HfO2/Ge by RF magnetron sputtering to be 5.9×1011 cm-2 · eV-1. These results have summarized that the heat treatment after the fabrication of MIS strucures have affected interface properties of germanate/Ge and oxide/Ge.Although the mechanism by which the process conditions act on the interface state is now under estimation, it has been speculated that the fabrication method, the insertion of the interlayers, and the application of heat treatment have a great influence on the interface characteristics. The structures and the fabrication method of various MIS will be discussed.Part of this work was carried out under the Cooperative Research Project Program of the Research Institute of Electrical Communication, Tohoku University.

Transient liquid phase bonding of Inconel 625 with Mar-M247 superalloy using Ni–Cr–B interlayer: Microstructure and mechanical properties

The transient liquid phase (TLP) bonding of Inconel 625 with Mar-M247 superalloy was performed using Ni–Cr–B interlayer material. The effects of bonding time and temperature on the microstructure evolution and mechanical properties of the joints of the dissimilar superalloys were investigated. Results showed that the precipitated phases in the diffusion affected zone (DAZ) on both sides of the joint were M5B3- and M3B2-type borides on the grain boundary and needle-like M5B3-, granular M5B3-, and M3B2-type borides in the grain. In addition, granular HfTaC2 and fine γ′ particles precipitated in the isothermally solidified zone near the Mar-M247 matrix. The non-isothermally solidified zone (NSZ) was composed of Mo–Cr–Nb-enriched borides and Nb-rich nickel-based γ solid solution. The formation mechanism and the asymmetry caused by the differences in grain size and element composition of the TLP-bonded joint were discussed accordingly. The mechanical properties of the joints were found to be closely related to the number, size, and location of the precipitated borides. Given the high hardness and poor plastic deformation resistance, the considerable amount of large borides in the NSZ and DAZ became the preferential source of cracks and led to the decrease of the mechanical properties of the joints. The maximum tensile strength and elongation of 865 ± 11.4 MPa/42.2% were achieved when the joint was bonded at 1150 °C/60 min, at which point isothermal solidification completely occurred and only the discontinuous block or granular borides with an area fraction of 17.2% remained in the DAZ on the Inconel 625 side. Specimen fracture occurred within the Inconel 625 base metal.

Nanofiltration membrane embedded with hydroxyapatite nanowires as interlayer towards enhanced separation performance

The triple-layered composite nanofiltration (NF) membrane consisting of thin polyamide (PA) top layer covered on polymeric porous membrane with interlayer has been popularly accepted, even commercially applied, to solve the “trade-off” issue. The nanofiltration performance was determined by the physicochemical properties of all layers. In the current work, hydroxyapatite (HAP) nanowires were adopted as a new type of interlayer material. Its superiority of ultra-hydrophilicity and electronegativity made it a container of aqueous monomers. As a result, ultra-thin and defect-free PA layer with a thickness of ~28 nm was generated owing to the low piperazine (PIP) concentration and restricted diffusion. In addition, the ultra-hydrophilic polysulfone (PSf) support layer was also helpful to reduce mass transfer resistance. The prepared PA/HAP/PSf composite membrane presented high salt aqueous solution permeation (177 L m −2 h −1 under 6 bar), excellent divalent salt rejection (98.2% for Na 2 SO 4 ) and high mono/bivalent salt selectivity (19 for NaCl/Na 2 SO 4 mixed solutions). This work proposed a useful strategy to construct highly permeable and selective NF membrane. PA/HAP/PSf triple-layered electronegative nanofiltration membrane showing high selectivity to monovalent/bivalent ions • HAP nanowires were adopted as interlayer of composite NF membrane for the first time. • The prepared PA/HAP/PSf NF membrane possessed ultra-thin and robust electronegative PA layer. • High rejection of 98.2% and salt permeation of 177 L m −2 h −1 under 6 bar for Na 2 SO 4 were achieved.

Mechanistic-Empirical Faulting Prediction Model for Unbonded Concrete Overlays of Concrete

Transverse joint faulting is a distress that develops in unbonded concrete overlays (UBOL). Historically, faulting models used for predicting the performance of a UBOL have not accounted for the effects of the interlayer between the overlay and the existing pavement on the development of faulting. This is a significant limitation since characteristics of the interlayer play a primary role in the rate at which faulting develops in UBOLs. To develop a more robust faulting prediction model for UBOLs, enhancements were made to the current process to address this limitation. This includes the use of a structural response model that can account for the effects of the interlayer properties on the response of the UBOL. Additional enhancements include the use of a deflection basin of the overlay (in lieu of corner deflections of an equivalent slab system for accumulating differential energy [DE]), the incorporation of an erosion model that can account for the erodibility of the interlayer material, the adjustment of the incremental faulting equations to accommodate small slab sizes that are common in UBOLs, and a national calibration using faulting data from in-service UBOLs. This enhanced faulting model has been implemented in the mechanistic-empirical design tool Pitt UBOL-ME.

Experimental study and comparison of different fully transparent laminated glass beam designs

Laminated glass beams without metallic or polymeric reinforcements generally lack post-breakage strength and ductility. This paper aims to perform a comparative study by testing five different fully transparent laminated glass beam designs in order to see how parameters such as the number and thickness of glass sheets (3 x 10 mm or 5 x 6 mm), the interlayer material (PVB Clear or SentryGlas), and the thermal treatment of glass (annealed or heat-strengthened) affect the pre-breakage performance and post-breakage safety. A buckling analysis is also performed using a numerical model with ABAQUS CAE. The study includes a comparison between the results of different experimental mechanical tests on laminated glass beams, including the tests presented in this paper, as well as other tests found in the literature. All designs presented a linear elastic behaviour until initial breakage. The interlayer material mainly affected the crack shape of laminated glass beams. Beams with five sheets of annealed glass had a more progressive breakage, and therefore a safer behaviour, than beams with three sheets of annealed or heat-strengthened glass.

Wide Working Temperature Range Rechargeable Lithium–Sulfur Batteries: A Critical Review

AbstractAt the technological forefront of energy storage, there is still a continuous upsurge in demand for high energy and power density batteries that can operate at a wide range of temperature. Rechargeable lithium sulfur batteries stand out among other advanced cell concepts owing to their ultrahigh theoretical gravimetric energy density characteristic as well as merits of low cost and environmental friendliness. Although achieving good operability of ambient lithium sulfur batteries, extending their workability to both higher and lower temperatures is also of paramount importance especially for future task‐specific applications. As a first attempt, this review presents a comprehensive understanding on the advances, challenges, and future research directions on lithium sulfur batteries operating at both low and high temperature extremes. From a material perspective, the workability of sulfur‐containing cathode materials, advanced electrolytes (from conventional liquid to quasi‐ and all‐solid‐state electrolytes), lithium metal anodes and the electrochemically inert components (separators and interlayer materials) at extreme temperatures are thoroughly analyzed. The insurmountable challenges and mechanistic understandings caused by thermal changes are critically reviewed. Finally, potential future research directions and prospects for lithium sulfur batteries operated at a wide range of temperature are also proposed.

Recent advances of organometallic complexes in emerging photovoltaics

AbstractOrganometallic complexes (OMCs) consisting of organic and metal active moieties have shown immense potential for application in solar cells. The diverse structure, rich porosity, and unique charge centers of OMCs enable them to be functional in solar cells. In this review, we introduced four types of OMCs, such as crown organometallic complexes, β‐diketone metal complexes, cyclometallic complexes, and main chain metal‐containing polymers, providing an in‐depth analysis of the structure‐performance relationship. OMCs could serve as active or interlayer materials in a variety of solar cell systems such as organic solar cells, perovskite solar cells, and dye‐sensitized solar cells, especially some metals to improve the photoelectric performance of the device as dopants. In the end, perspectives on the opportunities and challenges of OMCs are given.