Metal-organic framework (MOFs) deriving absorbers are booming due to their high specific surface area and porosity, flexible regulation of components and morphologies, rich physical and chemical properties. Firstly, the merits of MOFs for EW absorption combining with mainstream absorption mechanisms are dissected, and then we summarize the state-of-art development of the component-dominated MOFs and derivatives, and the components-performances relation is analyzed by discussing the impedance matching and attenuation capacity in detail. Furthermore, the MOFs deriving EWAs with multifunction are briefly introduced. Finally, the bottlenecks and outlook are proposed based on their current development. One of the main purposes of this review is to introduce MOFs deriving absorbers to researchers by investigating the latest advances, which can also offer guidance for novel MOFs deriving absorbers.

Designing cost-effective and high-active urea oxidation reaction (UOR) catalysts through interface engineering is highly imperative for the hydrogen economy. Unfortunately, the majority of reported studies focus on empirical exploration and seldom elucidate the modulation principle of interface engineering on the electronic structure for optimizing the catalytic UOR activity, hindering the rational construction of high-performance catalysts. In response, the Ni5P4/NiSe nanoplates with abundant interfaces are experimentally fabricated on the macroporous Ni foam substrate. The density functional theory (DFT) predictions decipher accelerated charge transmission at the Ni5P4/NiSe interfacial area, accompanied by the formation of a moderate d-band center. Subsequently, the dehydrogenation dynamics of the Ni5P4/NiSe heterojunction is effectively improved during the stepwise UOR process. As expected, the elaborate Ni5P4/NiSe exhibits outstanding UOR activity under tough environments (6.0 M KOH with urine or 0.5 M urea), further corroborating its prospects as excellent UOR catalysts for industrial applications.

Potassium ion batteries (PIBs) are identified as an imperative alternative for next-generation energy storage devices due to its abundant reserves. Even potassium (K) metal is a promising anode for its high theoretical capacity and intrinsic low potential, however, it still suffers from uncontrollable dendrite growth. Herein, a dendrite-free K anode is obtained by plating K metal on MoS2-modified carbon cloth (MoS2/CC@K). Specifically, MoS2 undergoes a series of phase transitions from initial MoS2 to KxMoS2 and final K2S4 with gradual insertion of K, then K metal is uniformly deposited on K2S4 with further discharging. This phase transition significantly reduces the K nucleation energy barrier. The strong interaction between K and K2S4 interface induces K in uniformly depositing to suppress the formation of K dendrites. Owing to these merits, the symmetric MoS2/CC@K cells exhibit low voltage hysteresis and superior cycling stability. When paired with perylene-3,4,9,10-tetracarboxylic diimide (PTCDI) cathode, the full cells display superior rate capability and long lifespan (10,000 cycles). Additionally, this strategy is also performed on Li and Na metal anodes, the MoS2/CC substrate still expresses superior electrochemical performance. This work provides a new view to induce the uniformly deposition of K, Li and Na metals.

As a classical magnetic material, spinel ferrite materials have been widely studied in the field of microwave absorption. However, due to their low conductivity and uncontrollable self-aggregation, their practical application has been greatly constrained. Now, a novel multi-interfacial one-dimensional (1D) magnetic ferrite@C fibers composites were synthesized by a facile electrospinning and annealing process. Through effective structural design and component adjustment, Zn-based ferrites were successfully confined into 1D carbon fibers. This structure brings about a large number of heterogeneous interfaces, while avoiding magnetic aggregation. Impressively, the results indicate that as-prepared ferrite@C fibers exhibit excellent EM absorption properties. The minimum reflection loss can reach up to −47.42 dB at 13.52 GHz with a matching thickness of 2.5 mm. In the meantime, a super-wide effective absorption bandwidth of 9.28 GHz (8.24–17.52 GHz) is obtained at 3.3 mm, which almost concurrently achieves coverage for X and Ku-bands. This study provides a feasible path to design novel and efficient magnetic ferrite/dielectric absorbers.

In this article, we demonstrate how commercial-scale reproducible GaN nanowires (GNWs) passivated with metal oxide overlayers and assisted by an efficient co-catalyst with a visible absorption wavelength can be used as a high-performance photoanode for photoelectrochemical (PEC) water splitting to produce solar-driven hydrogen. The facile growth of GNWs using a vapor-liquid-solid method by metal-organic chemical vapor deposition (MOCVD) raises the density of the NWs, increasing the active area for the water splitting reaction and facilitating charge transport. The passivation of surface defects through overlayers and being aided by a co-catalyst with a photo absorption range in the visible region greatly increases the photocurrent density up to 4.6 mA/cm2 under 1 sun illumination at zero applied biasing versus the reference electrode. The measured solar to hydrogen conversion efficiency of 6.4% is among the highest documented values for GNWs-based photoanodes grown using MOCVD.

The critical current density at high magnetic fields of high-temperature superconducting single crystals and films is mainly determined by the flux pinning force arising from interactions between fluxons and crystalline defects or secondary phases. However, iron-based superconductors, which are acknowledged as promising candidates for high-field applications, suffer from a lack of strong flux pinning centers. It leads to a critical current density (Jc) inferior to that of iron-based superconducting films. In this work, we applied a simple annealing method to tailor flux pinning structures in slightly underdoped BaFe2-xNixAs2 single crystals without significantly compromising superconductivity. We propose that the probable strengthened orthorhombic distortion by post-annealing could generate twin domain boundaries or short-range antiferromagnetic clusters with sizes comparable to the in-plane coherence length. The inclusion of the abnormal structural/magnetic domains enhances electron scattering but also provides potent flux pinning centers. Ultimately, the Jc is enhanced by 2.5 times in the samples with optimized pinning landscapes. Our studies highlight the importance of further exploring underdoped iron-based superconductors, in which magnetic/orthorhombic phases that compete and coexist with superconductivity may also act as effective pinning centers.

Defects within perovskite layers are considered to be a primary factor that inhibits nonlinear optical (NLO) performance, and mitigating or eliminating them is indispensable for the implementation of high-performance perovskite-based photonic and energy devices. Herein, we propose a novel defect modulation strategy through binding the functional groups at the axial positions of porphyrins with the defects of perovskites. Two axially-coordinated porphyrin molecules (TiOPr and SnOHPr) were utilized as effective functional additives to passivate the defects and control perovskite crystallization, while the role of axial functional groups of porphyrins has been systematically studied. Z-scan measurement results demonstrate that porphyrin-treated perovskite films exhibit prominently enhanced optical absorption nonlinearities under ultrafast femtosecond (fs) laser excitation at 800 nm in comparison to the MAPbI3 perovskite film, the NLO absorption coefficient (β) values for the modified films are approximately one or two orders of magnitudes superior to that of the pristine film. This significant improvement in NLO performance likely stems from the increased photoinduced ground-state dipole moment of the perovskite film treated by porphyrin during the process of two-photon absorption (TPA), and their photoinduced charge/energy transfer between perovskite and porphyrin. Particularly, the MAPbI3/SnOHPr film displays the largest β values (636.92–6621.42 cm GW−1) among all measured samples at different irradiation energies and a low optical limiting threshold of 5 mJ cm−2, which may profit from the dual-functional passivation effect of SnOHPr onto perovskite, suggesting its great potential as optical limiters. These observations strongly indicate that porphyrin-axial passivated perovskite films are outstanding material candidates for optical limiting applications towards ultrafast fs laser pulses in the near-infrared region. Our work affords a feasible paradigm for constructing high-performance NLO perovskite materials through porphyrin-axial passivation of defects.

High-entropy energy conversion and storage based on triboelectric nanogenerators (TENGs) has attracted substantial interest in recent years. Not only a large number of theoretical models but also experimental works have been focusing on confirming optimum conditions and prediction of maximum outputs of TENGs, which is in order to enlarge power generation and energy conversion efficiency. A complete power analysis of TENG systems includes the mechanical input (mechanical port), a TENG transducer, and electrical output (electrical port). However, the relationships between the external force driving TENG and the generated instantaneous power as well as the energy flowing inside TENGs remain elusive. Here, a dynamic field-circuit coupling model composed of a quasi-electrostatic field and an external circuit is established that allows the determination of the force distribution and power flow of a TENG transducer. It is confirmed that dissipation in TENGs is entirely electrical and caused by the separation of charges distributed in contacting surfaces and metal electrodes. Importantly, in steady-state operation, all input energy is converted into electrical (useful) power unless dissipation mechanisms (mechanical and electrical). In addition, the essential factors which affect the basic output characteristics of TENGs are discussed. This work suggests a new approach to fully understanding the whole dynamic power-delivering process within TENGs which is essential for the theoretical optimization of TENG performance and practical applications of TENGs.

Ultraviolet (UV) radiation is known to promote health concerns that can manifest over both short and long terms. Aging, sunburn, skin cancer, and other conditions are related to UV radiation. Medication can also be negatively affected by this radiation. Moreover, UV radiation modifies the taste, colour, and texture of food, and may compromise its suitability for human consumption. Therefore, the development of UV-shielding materials attracts considerable research interest for numerous applications, such as UV-light resistant packaging, sunscreens, contact lenses, coatings, and even clothes. UV-shielding materials arise from the dispersion of a UV-absorber of inorganic (such as ZnO, TiO2, CeO2) or organic (such as lignin, nanocellulose) nature into a matrix of high transparency (usually polymer or glass based). The most common types of UV-absorbers are semiconductor particles, quantum dots, or a hybrid approach combining both.However, inhomogeneous dispersion and large size distributions of the absorbing agent(s) usually compromise the transparency of the UV-shielding material. The goal of the current study is to present the newest and most innovative approaches regarding the development of nanostructured transparent solutions for UV-shielding.

Infrared nonlinear optical (IR-NLO) crystals have attracted many attentions due to the frequency-conversion capability to generate coherent tunable IR laser output for military and civil applications. Chalcogenides as a most popular branch of IR-NLO materials are the competitive candidates owing to their large second-harmonic generation (SHG) coefficient (deff) and broad transmission regions. Currently, how to obtain the non-centrosymmetric (NCS) structure and realize the coexistence of wide energy gap (Eg ≥ 3.0 eV), sufficient deff (≥ 1.0 × AgGaS2), and beneficial phase-matching (PM) feature are the two major challenges faced in this field. The former can be effectively solved through the combination of local asymmetric units and chemical substitution strategy, while for the latter, there is no systematic survey and lack of universally applicable methodology. In this review, 40 IR-NLO chalcogendides are selected based on the aforementioned two challenges and divided into 7 types according to the different chemical components. The composition-structure-performance relationships and the theoretical origin of their IR-NLO properties are summarized systematically. At length, some useful information and development prospects were briefly discussed, which may offer new ideas and promote the discovery of IR-NLO materials with the ideal comprehensive performance.

Electrocatalytic reduction of nitrite (NO2−RR) is considered an effective method for removing harmful NO2− in wastewater while simultaneously generating high-value-added ammonia (NH3). This process, however, requires electrocatalysts with high activity and selectivity. Herein, a MoSe2 nanosheet array with Se vacancies supported on carbon cloth (MoSe2– x/CC)is proposed as a high-efficiency electrocatalyst for NO2− reduction to NH3. In 0.1 M phosphate-buffered saline with 0.1 M NO2−, MoSe2–x/CC exhibits an outstanding NH3 yield of 446.0 μmol h−1 cm−2 and a Faradaic efficiency of 96.9%, overpassing that of MoSe2/CC (278.1 μmol h−1 cm−2, 83.1%). Additionally, density functional theory calculations gain insights into reaction mechanism of MoSe2–x towards NO2−RR.

Electrocatalytic reduction of six-electron nitrite (NO2−) to NH3 is a very promising avenue for the effective removal of widespread nitrite from groundwater and the generation of high-value-added products. Herein, we investigated Ni–Mo–P nanoparticles decorated TiO2 nanoribbon arrays as an efficient NO2−RR catalyst. Tested in 0.1 M NaOH with 0.1 M NO2−, a high NH3 yield of 16124.8 μg h−1 cm−2 and an ultrahigh faradaic efficiency of 95.6% at −0.6V can be achieved. The excellent catalytic performance of Ni–Mo–P/TiO2 can be attributed to the synergistic effect of Ni–Mo–P and TiO2 heterojunction, together with abundant active sites. In addition, the Zn–NO2− battery with Ni–Mo–P/TiO2 as the anode exhibits excellent battery performance, its power density can reach 6.0 mW cm−2, and a large amount of NH3 can be produced while generating electricity.

The lattice thermal conductivity of stable 18-electron Ti2FeNiSb2 compound is remarkably lower than that of the traditional ternary half-Heusler alloy, and it is considered a promising thermoelectric material. Owing to the distinctive performance of high entropy alloys, we designed a novel valence-balanced double half-Heusler Ti2Zr2Hf2NbVFe5Ni3Sb8 alloy with high entropy sublattice. The experimental results showed that enhanced electrical transport properties and reduced thermal conductivity of the alloy were achieved. The thermal conductivity at room temperature was two fifths of that of reported Ti2FeNiSb2 and the maximum power factor improved three times. The ultralow theoretical minimum lattice thermal conductivity was estimated to be less than 0.2 W m−1K−1, showing the possibility for further reduction. Phonon spectrum calculation showed that the high entropy strategy was valid for scattering phonons and limiting lattice thermal conductivity. A peak ZT ∼0.027 at 823 K was achieved, which is almost five times that of the Ti2FeNiSb2. This work demonstrates the effectiveness of the high entropy strategy in double half-Heusler compounds and the potential of the new concept of HE-DHH compounds as high-performance thermoelectric materials.

Exploring new materials with complex structures and excellent transport properties has always been a fascinating topic in thermoelectrics. Recently, (GeTe)n(Sb2Te3)m-based compounds (GSTs), a well-known family of phase-change materials, are found to be promising thermoelectric candidates. Rooted in but different from the parent GeTe and Sb2Te3 binary compounds, these pseudo-binary alloys exhibit special structures and good transport properties. Here in this review, we demonstrate some fundamental knowledge and recent progress on these GST materials for thermoelectric applications. The operation principle of phase-change memory, crystal structure, as well as the special metavalent bonding mechanism are introduced at first. Then the electrical and thermal transport properties are illustrated, which are associated with material structures and bonding features. Several strategies are discussed to enhance the thermoelectric performance of hexagonal GSTs. Then, this review extends to discuss a larger family of (AC)n(B2C3)m thermoelectric materials (A = Si, Ge, Sn, Pb; B = As, Sb, Bi; C = S, Se, Te), which share similar crystal structures and transport properties with hexagonal GSTs. Finally, some possible research directions are proposed for the future study on thermoelectric GSTs.

Rationally designing inorganic compounds with the specific functional property is still a great challenge. Herein, the first metal selenite Ga2(Se2O5)2(HSeO3)(H2SeO3)F containing three different kinds of Se–O groups and Ga(Se2O5)(HSeO3) have been successfully synthesized by the hydrothermal method. In Ga(Se2O5)(HSeO3), the polar GaO6 octahedra and Se–O groups arrange in opposite directions, resulting in its centrosymmetric (CS) crystal structure, whereas in Ga2(Se2O5)2(HSeO3)(H2SeO3)F, by combining the chemical tailoring with the structure-directing properties of F− anions, unprecedented lantern-like polar structural clusters [Ga2F(Se2O5)4(HSeO3)2]5- are constructed, and these clusters adopt well-ordered alignments along the c axis promoting its noncentrosymmetric (NCS) and polar structure. Structural analysis indicates that the bifunctional F− anion plays the importantly polar ‘lighted’ roles for designing and synthesizing NCS and polar material of Ga2(Se2O5)2(HSeO3)(H2SeO3)F. The electron densities of states (DOS) calculations suggest that the interaction between oxygen and selenite determines their band gaps and the introduction of large electronegative F− anions obviously widens the UV cut-off edge of Ga2(Se2O5)2(HSeO3)(H2SeO3)F. In addition, performance measurements including powder second-harmonic generation (SHG), thermal analysis and infrared and UV-vis-NIR diffuse reflectance spectroscopy were performed on the title compounds.

Boron's unique electron deficiency allows for the formation of various borophene polymorphs that have the potential for superconductivity. Herein, we have introduced a new route to realize high superconductivity in borophene through kagome and honeycomb boron layers assembly. We have designed a tri-layer borophene, named hP8-B, consisting of two AA-stacked kagome layers with a honeycomb layer serving as the interlayer. hP8-B possesses high superconductivity with an estimated Tc of 35.6 K, holding the highest value in any elemental 2D materials. The high Tc is mainly contributed by the strong coupling of σ-bonding electrons of the kagome layers and in-plane vibrational modes, which differs from that in other superconductive borophene polymorphs. Electronic band structure calculations showcase the existence of a Dirac cone near the Fermi level, indicating that hP8-B may be a potential topological superconductor. The superconductivity of hP8-B can be enhanced to 46.4 K under a biaxial tensile strain of 3% and doping density of 0.0375 holes per atom, due to the softening of the in-plane vibrational modes.

Extensive crystal structure prediction searches provide evidence of two 3D structures with orthorhombic (Immm) and monoclinic (C2/m) space groups as reasonable candidates for the first pressure-induced phase of 1T-HfSe2. Our candidates are compared with two recent proposals that keep the 2D nature of the ambient conditions phase and display hexagonal (P63/mmc) and monoclinic (C2/m) symmetry, although the latter has a different structure than our proposed C2/m phase. Both of these 2D-like structures are discarded based on simple thermodynamic and kinetic arguments that can be extended to explain the pressure-induced polymorphic sequence of other transition metal dichalcogenides. The computed observables of our orthorhombic phase are fully consistent with the experimental structural and Raman data observed at low and high-pressure.

Aluminum finned heat sinks are commonly used for cooling electronics and high-power systems through convective heat transfer, but their cooling efficiency per unit volume is a major bottleneck to further improve performance or compactness of device/system. Here we report a new strategy including surface modification and system design that for the first time allowed commercially available aluminum finned heat sinks to perform capillary-driven water evaporation from entire surface of fins for significant cooling enhancement. The capillary wicking ability was attributed to a nanostructured surface resulting from the surface modification. Experimental results showed that the passive cooling power of this nano-capillary evaporative finned heat sink (EF-HS) was about 7.8–8.4 times higher than that of a regular (unmodified) heat sink under natural convection. The new strategy can potentially reduce the fin height, cut material costs and save space without compromising heat dissipation efficiency, which is favorable for both large-scale power systems and compact devices. Using photovoltaic (PV) solar panel cooling as an example, the EF-HS with only 9 mm fin height was able to reduce the PV panel temperature by 15.5 °C (26.4%) in a windless condition and increase the energy conversion efficiency by 12.7%.

A skin-attachable invisible display offers a new opportunity in next-generation electronic application, such as smart contact lenses, human-machine health monitoring interfaces and soft electronic skins. In response to this trend, transparent organic light-emitting diodes (OLEDs) offer enormous advantages in future skin-attachable invisible displays, including excellent flexibility and superior efficiency. Although several approaches reported recently attempt to manufacture transparent and flexible OLEDs, it is still a tremendous challenge to simultaneously meet the desired optical and mechanical properties. Herein, we develop a feasible strategy to achieve transparent and conformable OLEDs (TC-OLEDs). Benefiting from the intrinsic high transparency and outstanding deformability of our electrodes, the whole device shows high transmittance up to 85.0% at a wavelength of 400 nm and high mechanical flexibility with skin-like conformability. More strikingly, the resulting device maintains excellent photoelectric performance with a maximum current efficiency (CE) of 56.8 cd/A and external quantum efficiency (EQE) of 17.1%. Based on the versatile TC-OLEDs, we also report an all-organic and all-conformable invisible display driven by transparent and conformable organic thin film transistors (TC-OTFTs) for the first time. This work offers a meaningful guidance for the construction of TC-OLEDs and the development of skin-attachable invisible displays.

Efficient spatial separation of photogenerated carriers is the key to achieving photocatalytic oxidation reduction synergistic reactions, and the built-in electric field generated by piezoelectric effects can provide a strong driving force for charge separation. A novel Pt/ZnIn2S4/BaTiO3 (PBZIS) piezo-photocatalyst with spatial charge separation was successfully constructed through two-step hydrothermal and photodeposition methods. Due to the special 1D/2D core/shell structure, the inner BaTiO3 can served as hole-storage layer, while the outer Pt nanoparticles can acted as electron capture center, thus greatly improving the separation of photo generated charge carriers and achieving spatial separation of redox sites. Under the ultrasound, the polarized electric field induced by the piezoelectric effect can further improve the extraction rate of photo generated holes by BaTiO3 and accelerate surface catalytic reactions. Therefore, the synergism of electron/hole co-extraction and piezoelectric effect construct a directional transmission channel and target active sites for photogenerated electron-holes over PBZIS heterojunctions, reuslting in the highest performance for photocatalytic cooperative H2 evolution (1335.3 μmol g−1 h−1) and HMF oxidation (1070.8 μmol g−1 h−1). This work would inspire the development of high-performance piezo-photocatalysts for the cooperative biomass oxidation coupling with high efficient hydrogen evolution.