The interest in all-inorganic halide perovskites has been increasing dramatically due to their high quantum yield, band gap tunability, and ease of fabrication in compositional and geometric diversity. In this study, we synthesized µm long and ~4 nm thick CsPbBr3 nanowires (NWs). They were, then, integrated into electrospun polyurethane (PU) fibers to examine polarization behavior of the composite fiber assembly. Aligned electrospun fibers containing CsPbBr3 nanowires show remarkable increase in degree of polarization from 0.17 to 0.30. This combination of NWs and PU fibers provides a promising composite material for various applications such as optoelectronic devices and solar cells.

Recent advances in colloidal synthesis methods have led to increased research focus on halide perovskites. Due to highly ionic crystal structure of perovskite materials, stability issue pops up especially against polar solvents such as water. In this study, we investigate water-driven structural evolution of CsPbBr 3 by performing experiments and state-of-the-art first-principles calculations.It is seen that while optical image shows the gradual degradation of yellowish-colored CsPbBr 3 structure under daylight, UV illumination reveals that the degradation of crystals takes place in two steps; transition from blue-emitting to green-emitting structure and and then transition from green-emitting phase to complete degradation. We found that as-synthesized CsPbBr 3 NWs emit blue light under 254 nm UV source and before the degradation, first CsPbBr 3 NWs undergoes a water-driven structural transition to form large bundles. It is also seen that formation of such bundles provide longer-term environmental stability. In addition theoretical calculations revealed how strong is the interaction of water molecules with ligands and surfaces of CsPbBr 3 and provide atomistic-level explanation to transition from ligand-covered nanowires to bundle formation. Further interaction of green-light-emitting bundles with water causes complete degradation of CsPbBr 3 and photoluminescence signal is entirely quenched. Moreover, Raman and XRD measurements revealed that completely degraded regions are decomposed to PbBr 2 and CsBr precursors. We believe that findings of this study may provide further insight into the degradation mechanism of CsPbBr 3 perovskite by water.

The development of colorimetric mechanical sensors (force, pressure, strain, and impact) allows to visualize any existing structural deformation of a system occurring upon a mechanical action via naked eyes. The...

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Organo-metallic europium complex tetrakis (dibenzoyl methide) triethylammonium (EuD4TEA) shows a sharp emission spectrum, which makes it interesting for photonic applications. In this work, we embedded it into all-polymeric planar microcavities and investigated the effect of the photonic environment on its emission spectrum. To this end, submicron-sized EuD4TEA crystals were loaded into a blend of polystyrene and carboxylic terminated polystyrene matrix, which served to stabilize the emitter in the polymer and to make the composite processable. The new composite was then casted by spin-coating as a defect layer in a polymeric planar microcavity. Spectroscopic studies demonstrate that fine spectral tuning of the cavity mode on the sharp organometal luminescence is possible and produces spectral redistribution of the fluorophore emission, along with a remarkable cavity quality factor.

Cesium lead perovskites, in the form of CsPbX 3 or Cs 4 PbX 6 , have been widely used for various optoelectronic applications due to their exceptionally good optical properties. In this study, the effect of Mn doping on the structural and optical properties of cesium lead halide perovskite crystals are investigated from both experimental and theoretical points of view. It is found that adding MnCl 2 during the synthesis not only leads to a Mn-driven structural phase transition from Cs 4 PbBr 6 to CsPbCl 3 but also triggers the Br − to Cl − halide exchange. On the other hand, it is observed that, under UV illumination, the color of Mn-doped crystals changes from orange to blue in approximately 195 h. While the intensity of Mn-originated photoluminescence emission exponentially decays in time, the intensity of CsPbCl 3 -originated emission remains unchanged. In addition, diffusive motion of Mn ions results in both a growing population of MnO 2 at the surface and transition of the host into a cesium-rich Cs 4 PbCl 6 phase.

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Silica/silicate scaling is one of a few detrimental problems that cause high economical loss in the geothermal and petroleum fields. The prevention of silica/silicate has been attempted using antiscalants with functional groups, particularly −NH 2 ; however, metal silicates are commonly found in the fields, and the antiscalants developed thus far are not effective against these compounds. In this work, polymeric antiscalants have been developed by merging two or more functional comonomers consisting of various chelating groups for metal cations. Homo-and copolymers of acrylamide (AM), the sodium salt of vinyl sulfonic acid (VSA), and vinyl phosphonic acid (VPA) were synthesized to examine their antiscaling performance against metal silicate scaling. Lab-scale metal silicates were obtained in a pressured autoclave reactor. The antiscalants were tested at various dosages (25, 50, and 100 ppm), and their effects were investigated from the leftover decantates after isolation of the solid precipitates. The polymeric antiscalants were found to be particularly effective against metal silicates and ineffective against simple silica precipitates. Acidic groups may be coordinating the metal cations, which prevents the formation of precipitates. Among these acidic comonomers, VSA-containing polymers, in particular, increased the solubility of metal silicates.