Hysteretic Piezochromism in a Lead Iodide-Based Two-Dimensional Inorganic-Organic Hybrid Perovskite.

Two-dimensional inorganic-organic hybrid perovskites are in the limelight due to their potential applications in photonics and optoelectronics. They are environmentally stable, and their various chemical compositions offer a wide range of bandgap energies. Alternatively, crystal deformation enables in situ control over their optical properties.

Controlled Reduction of Sn in the Complex Iodide CsSnI with Metallic Gallium.

Metal gallium as a low-melting solid was applied in a mixture with elemental iodine to substitute tin(IV) in a promising light-harvesting phase of CsSnI by a reactive sintering method. The reducing power of gallium was applied to influence the optoelectronic properties of the CsSnI phase via partial reduction of tin(IV) and, very likely, substitute partially Sn by Ga. The reduction of Sn to Sn in the CsSnI phase contributes to the switching from -type conductivity to n-type, thereby improving the total concentration and mobility of negative-charge carriers.

Silver Eco-Solvent Ink for Reactive Printing of Polychromatic SERS and SPR Substrates.

A new reactive ink based on a silver citrate complex is proposed for a photochemical route to surface-enhanced Raman spectroscopy active substrates with controllable extinction spectra. The drop-cast test of the ink reveals homogeneous nucleation of silver and colloid particle growth originating directly from photochemical in situ reduction in droplets, while the following evaporation of the deposited ink produces small nano- and micron-size particles. The prepared nanostructures and substrates were accurately characterized by electron microscopy methods and optical extinction spectroscopy.