Heterointerfaces formed by the intimate connection of different materials with electromagnetic losses are expected to achieve stronger electromagnetic (EM) absorption. However, constructing composites with heterointerfaces still faces great challenges in facile preparation process, optimized impedance matching, high reflection loss (R_L), and ultrathin matching thickness. In this work, we develop ZIF-8 functionalized MXene to produce hierarchical Ti₃C₂@C@ZnO composites with heterointerface to advance EM absorption enhancement. Modified with polydopamine (PDA), few-layer Ti₃C₂T_x MXene sheets enable adsorption of Zn²⁺ metal ions on Ti₃C₂T_x@PDA by electrostatic interaction for in-situ growth of ZIF-8. Ti₃C₂/C/ZnO heterointerface were obtained after heat treatment of Ti₃C₂T_x@PDA@ZIF-8 nanocomposites at various temperatures. The Ti₃C₂/C/ZnO-600 °C with 1.15 mm thickness have a R_L of −50.241 dB and an effective absorption bandwidth of 3.50 GHz. In-depth studies on the electromagnetic loss mechanisms reveal that Ti₃C₂, carbon, and ZnO in nanocomposites generate multiple interfacial polarization losses beyond partial conductivity losses caused by Ti₃C₂ and ZnO. Oxygen vacancy defects in ZnO form dipole losses with carbon. This work not only provides a simple and effective concept for preparing MXene@MOFs heterogeneous composites as an ultrathin and strong electromagnetic wave absorber, but also offers a vital guideline to fabricate various metal oxides derived from the MXene and metal-organic frameworks (MOFs) precursors.

Semiconductive metal–organic frameworks (MOFs) have attracted great interest for the electronic applications. However, dark currents of present hybrid organic–inorganic materials are 1000–10,000 times higher than those of commercial inorganic detectors, leading to poor charge transportation. Here, we demonstrate a ZIF-8 (Zn(mim)₂, mim = 2-methylimidazolate) wafer with ultra-low dark current of 1.27 pA·mm⁻² under high electric fields of 322 V·mm⁻¹. The isostatic pressing preparation process provides ZIF-8 wafers with good transmittance. Besides, the presence of redox-active metals and small spatial separation between components promotes the charge hopping. The ZIF-8-based semiconductor detector shows promising X-ray detection sensitivity of 70.82 μC·Gy⁻¹·cm⁻² with low doses exposures, contributing to superior X-ray imaging capability with a relatively high spatial resolution of 1.2 lp·mm⁻¹. Simultaneously, good peak discrimination with the energy resolution of ~ 43.78% is disclosed when the detector is illuminated by uncollimated ²⁴¹Am@5.48 MeV α-particles. These results provide a broad prospect of MOFs for future radiation detection applications.

Metal-insulator-metal (MIM) cavity as a lithography-free structure to control light transmission and reflection has great potential in the field of optical sensing. However, the dense top metal layer of the MIM prohibits any external medium from entering the dielectric insulation layer, which limits the application of the cavity in the sensing field. Herein, we demonstrate a series of monolithic metal-organic frameworks (MOFs) based MIM cavities, which are treated by plasma etching to provide channels for chemical diffusion and to advance sensing. We modulate the bandwidth of the MIM filters by controlling the MOF thickness as insulator layers. Oxygen plasma-etching is applied to build channels on the top metal layer without altering their saturation and brightness for chemical sensing performance. The etching time regulates the number and size of channels on the top metal layer. Sensing behavior is demonstrated on the plasma-etched MOFs-based MIM cavity when external chemicals diffuse in the cavity. In addition, we generate patterned structure of the MOFs-based MIM cavity via plasma-mask method, which can transfer to different substrates and produce a controllable structure color change for chemical sensing. Our MIM cavity may promote the advancement and applications of structural color in security imaging, color display, information anticounterfeiting, and color printing.

The temperature gradient solution method can effectively reduce the growth temperature of zinc telluride (ZnTe) crystal. However, it is inevitable to introduce Te inclusions in the as-grown ZnTe crystals, leading to degrading the crystal quality. In this paper, the Te inclusions under saturated Zn vapor were eliminated via both isothermal annealing and gradient annealing. The removal efficiency of Te inclusions was evaluated, which was determined by the annealing temperature and gradient. A removal efficiency of 83% is achieved via gradient annealing at 650 ℃ for100 h. In addition, V_Te–Te_i complex defects caused by Te atoms diffusion appear in the crystal after annealing, thus affecting the crystal quality and photoelectric properties of the ZnTe crystal. Based on the X-ray double-crystal rocking curves of the ZnTe crystal, the crystal quality is generally improved when the Te inclusions are removed, indicating that the Te inclusions are a dominated factor affecting the quality of ZnTe crystal.