Controlled Ligand-Free Growth of Free-Standing CsPbBr Perovskite Nanowires.

Metal halide perovskite nanowires are widely studied due to their unique electronic and optical characteristics, making them promising for light emitting and detection applications. We developed a ligand-free method to grow vertically aligned free-standing CsPbBr nanowires from anodized aluminum oxide nanopore substrates. Here, we investigate the growth process using microscopy with ultraviolet and visible light excitation, revealing a highly dynamic process with pronounced fluorescence at locations where high-density free-standing nanowires could be found.

Ion Migration and Redox Reactions in Axial Heterojunction Perovskite CsPb(BrCl) Nanowire Devices Revealed by Operando Nanofocused X-ray Photoelectron Spectroscopy.

Metal-halide perovskites (MHPs) have gained substantial interest in the energy and optoelectronics field. MHPs in nanostructure forms, such as nanocrystals and nanowires (NWs), have further expanded the horizons for perovskite nanodevices in geometry and properties. A partial anion exchange within the nanostructure, creating axial heterojunctions, has significantly augmented the potential applications.

Single vertical InP nanowire diodes with low ideality factors contacted in-array for high-resolution optoelectronics.

Nanowire (NW) optoelectronic and electrical devices offer unique advantages over bulk materials but are generally made by contacting entire NW arrays in parallel. In contrast, ultra-high-resolution displays and photodetectors require electrical connections to individual NWs inside an array. Here, we demonstrate a scheme for fabricating such single NW vertical devices by contacting individual NWs within a dense NW array.

Structural and chemical properties of anion exchanged CsPb(BrCl)heterostructured perovskite nanowires imaged by nanofocused x-rays.

Over the last years metal halide perovskites have demonstrated remarkable potential for integration in light emitting devices. Heterostructures allow for tunable bandgap depending on the local anion composition, crucial for optoelectronic devices, but local structural effects of anion exchange in single crystals is not fully understood. Here, we investigate how the anion exchange of CsPbBrnanowires fully and locally exposed to HCl vapor affects the local crystal structure, using nanofocused x-rays.

Nanoscale X-ray Imaging of Composition and Ferroelastic Domains in Heterostructured Perovskite Nanowires: Implications for Optoelectronic Devices.

Metal halide perovskites (MHPs) have garnered significant interest as promising candidates for nanoscale optoelectronic applications due to their excellent optical properties. Axially heterostructured CsPbBr-CsPb(BrCl) nanowires can be produced by localized anion exchange of pregrown CsPbBr nanowires. However, characterizing such heterostructures with sufficient strain and real space resolution is challenging.

Perovskite-Compatible Electron-Beam-Lithography Process Based on Nonpolar Solvents for Single-Nanowire Devices.

Metal halide perovskites (MHPs) have been studied intensely as the active material for optoelectronic devices. Lithography methods for perovskites remain limited because of the solubility of perovskites in polar solvents. Here, we demonstrate an electron-beam-lithography process with a poly(methyl methacrylate) resist based on the nonpolar solvents -xylene, hexane, and toluene.

Free-Standing Metal Halide Perovskite Nanowire Arrays with Blue-Green Heterostructures.

Vertically aligned metal halide perovskite (MHP) nanowires are promising for various optoelectronic applications, which can be further enhanced by heterostructures. However, present methods to obtain free-standing vertically aligned MHP nanowire arrays and heterostructures lack the scalability needed for applications. We use a low-temperature solution process to prepare free-standing vertically aligned green-emitting CsPbBr nanowires from anodized aluminum oxide templates.

Single-Crystalline Perovskite Nanowire Arrays for Stable X-ray Scintillators with Micrometer Spatial Resolution.

X-ray scintillation detectors based on metal halide perovskites have shown excellent light yield, but they mostly target applications with spatial resolution at the tens of micrometers level. Here, we use a one-step solution method to grow arrays of 15-μm-long single-crystalline CsPbBr nanowires (NWs) in an AAO (anodized aluminum oxide) membrane template, with nanowire diameters ranging from 30 to 360 nm. The CsPbBr nanowires in AAO (CsPbBr NW/AAO) show increasing X-ray scintillation efficiency with decreasing nanowire diameter, with a maximum photon yield of ∼5 300 ph/MeV at 30 nm diameter.