Research progress of functional MXene in inhibiting lithium/zinc metal battery dendrites.

The layered two-dimensional (2D) MXene has great promise for applications in supercapacitors, batteries, and electrocatalysis due to its large layer spacing, excellent electrical conductivity, good chemical stability, good hydrophilicity, and adjustable layer spacing. Since its discovery in 2011, MXene has been widely used to inhibit the growth of anode dendrites of lithium metal. In the past two years, researchers have used MXene and MXene based materials in the anodes of zinc metal batteries and zinc ion hybrid capacitors, respectively, and made a series of important progressive steps in the inhibition of zinc dendrite growth. In this review, we summarize the research progress of functional MXenes in inhibiting the growth of lithium and zinc metal anode dendrites, and provide a brief overview and outlook on the current challenges of MXene materials, which will help researchers to further understand the methods and their mechanisms, thus to develop novel electrochemical energy storage systems to meet the needs of rapidly developing electric vehicles and wearable/portable electronics.

High-performance ultraviolet detector based on self-assembled 3D/2D perovskite heterostructure.

Heterogeneous assembly of metal halide perovskites (MHPs) structures offers convenience for promoting the interfacial properties of perovskite heterojunctions, which have been widely used in the new generation of photoelectric devices. In this study, three-dimensional (3D) CsPbBr3 quantum dots (CPB QDs) were epitaxially grown on two-dimensional (2D) (BA)2PbBr4 nanoplates (BPB NPs) via self-assembly in a toluene mixing solution. The morphological, structural, and optical properties of the synthesized structure reveal that a highly-qualified interface and coherence were formed between the two different perovskites. These heterostructures (HSs) facilitate the separation and transportation of electrons and holes in opposite directions. Based on this property, a high-performance ultraviolet light detector was fabricated by depositing a layer of CPB@BPB film on a textured silicon (T-Si) substrate. The prepared CPB@BPB/T-Si detector has shown enhanced properties i.e. quick response time, high responsivity (6.9 A W-1), high detection rate (3.17 × 109 jones), and low detection limit (0.24 µW cm-2). This enhanced performance could be attributed to the large light-absorbing area, effective carrier transport channels in BPB NPs, and improved interfacial properties of the CPB@BPB HS.

Synthesis of centimeter-size two-dimensional hybrid perovskite single crystals with tunable, pure, and stable luminescence.

The environment-friendly synthesis and property modulation of two-dimensional organic-inorganic halide perovskite (2D OHP) single crystals with large sizes and high quality are important for the fabrication of optoelectric devices. In this work, plate-like and centimeter-size (BA)2Pb(BrxI1-x)4 (BA = n-butylammonium, x: 0-1) single crystals with high crystallinity were synthesized via the cooling crystallization method in a mixed HX (X: I, Br) acid aqueous solution. The synthesized samples were single-phase with homogenously distributed Br and I ions. The lattice structure and bandgap of (BA)2Pb(BrxI1-x)4 were both finely tuned through halide alloying. Pure photoluminescence with unitary wavelength was obtained in the mixed-halide samples compared to those of monohalides (BA)2PbI4 and (BA)2PbBr4. This is attributed to the structural homogeneity of the alloyed crystals. Moreover, the prepared (BA)2Pb(BrxI1-x)4 samples showed higher photo and thermal stability for a long duration even with ion migration. This study will be an important reference for the fabrication and property modulation of 2D OHP-based light-emitting and other optoelectric devices.