Black phosphorus-based van der Waals heterostructures for mid-infrared light-emission applications

Mid-infrared(MIR)light-emitting devices play a key role in optical communications,thermal imaging,and material analysis applications.Two-dimensional(2D)materials offer a promising direction for next-generation MIR devices owing to their exotic optical properties,as well as the ultimate thickness limit.More importantly,van der Waals heterostructures-combining the best of various 2D materials at an artificial atomic level-provide many new possibilities for constructing MIR light-emitting devices of large tuneability and high integration.Here,we introduce a simple but novel van der Waals heterostructure for MIR light-emission applications built from thin-film BP and transition metal dichalcogenides(TMDCs),in which BP acts as an MIR light-emission layer.For BP–WSe_(2) heterostructures,an enhancement of~200% in the photoluminescence intensities in the MIR region is observed,demonstrating highly efficient energy transfer in this heterostructure with type-Ⅰ band alignment.For BP-MoS_(2) heterostructures,a room temperature MIR light-emitting diode(LED)is enabled through the formation of a vertical PN heterojunction at the interface.Our work reveals that the BP-TMDC heterostructure with efficient light emission in the MIR range,either optically or electrically activated,provides a promising platform for infrared light property studies and applications.

One-Dimensional(NH=CINH_(3))_(3)PbI_(5)Perovskite for Ultralow Power Consumption Resistive Memory

Organic-inorganic hybrid perovskites(OIHPs)have proven to be promising active layers for nonvolatile memories because of their rich abundance in earth,mobile ions,and adjustable dimensions.However,there is a lack of investigation on controllable fabrication and storage properties of one-dimensional(1D)OIHPs.Here,the growth of 1D(NH=CINH_(3))_(3)PbI_(5)((IFA)_(3)PbI_(5))perovskite and related resistive memory properties are reported.The solution-processed 1D(IFA)_(3)PbI_(5)crystals are of welldefined monoclinic crystal phase and needle-like shape with the length of about 6 mm.They exhibit a wide bandgap of 3 eV and a high decomposition temperature of 206℃.Moreover,the(IFA)_(3)PbI_(5)films with good uniformity and crystallization were obtained using a dual solvent of N,N-dimethylformamide(DMF)and dimethyl sulfoxide(DMSO).To study the intrinsic electric properties of this anisotropic material,we constructed the simplest memory cell composed of only Au/(IFA)_(3)PbI_(5)/ITO,contributing to a high-compacted device with a crossbar array device configuration.The resistive random access memory(ReRAM)devices exhibit bipolar current-voltage(I-V)hysteresis characteristics,showing a record-low power consumption of~0.2 mW among all OIHP-based memristors.Moreover,our devices own the lowest power consumption and“set”voltage(0.2 V)among the simplest perovskite-based memory devices(inorganic ones are also included),which are no need to require double metal electrodes or any additional insulating layer.They also demonstrate repeatable resistance switching behaviour and excellent retention time.We envision that 1D OIHPs can enrich the low-dimensional hybrid perovskite library and bring new functions to low-power information devices in the fields of memory and other electronics applications.