By adopting a facile, environmentally benign, solution phase method under ambient conditions, we have successfully synthesized all-inorganic cesium lead halide perovskite 1D rods.

The magnetic properties of copper ferrite (CuFe2O4) nanoparticles prepared via sol-gel auto combustion and facile solvothermal method are studied focusing on the effect of nanoparticle arrangement. Randomly oriented CuFe2O4 nanoparticles (NP) are obtained from the sol-gel auto combustion method, while the solvothermal method allows us to prepare iso-oriented uniform spherical ensembles of CuFe2O4 nanoparticles (NS). X-ray diffractometry (XRD), atomic absorption spectroscopy (AAS), infra-red (IR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), (57)Fe Mössbauer spectroscopy and vibrating sample magnetometer (VSM) are used to investigate the composition, microstructure and magnetic properties of as-prepared ferrite nanoparticles. The field-dependent magnetization measurement for the NS sample at low temperature exhibits a step-like rectangular hysteresis loop (M(R)/M(S) ~ 1), suggesting cubic anisotropy in the system, whereas for the NP sample, typical features of uniaxial anisotropy (M(R)/M(S) ~ 0.5) are observed. The coercive field (HC) for the NS sample shows anomalous temperature dependence, which is correlated with the variation of effective anisotropy (K(E)) of the system. A high-temperature enhancement of H(C) and K(E) for the NS sample coincides with a strong spin-orbit coupling in the sample as evidenced by significant modification of Cu/Fe-O bond distances. The spherical arrangement of nanocrystals at mesoscopic scale provokes a high degree of alignment of the magnetic easy axis along the applied field leading to a step-like rectangular hysteresis loop. A detailed study on the temperature dependence of magnetic anisotropy of the system is carried out, emphasizing the influence of the formation of spherical iso-oriented assemblies.

Chemically derived topological insulator BiSe nanoflake/Si nanowire (SiNWs) heterojunctions were fabricated employing all eco-friendly cost-effective chemical route for the first time. X-ray diffraction studies confirmed proper phase formation of BiSe nanoflakes. The morphological features of the individual components and time-evolved hybrid structures were studied using field emission scanning electron microscope. High resolution transmission electron microscopic studies were performed to investigate the actual nature of junction whereas elemental distributions at junction, along with overall stoichiometry of the samples were analyzed using energy dispersive X-ray studies. Temperature dependent current-voltage characteristics and variation of barrier height and ideality factor was studied between 50 and 300 K. An increase in barrier height and decrease in the ideality factor were observed with increasing temperature for the sample. The rectification ratio (I/I) for SiNWs substrate over pristine Si substrate under dark and near-infrared (NIR) irradiation of 890 nm was found to be 3.63 and 10.44, respectively. Furthermore, opto-electrical characterizations were performed for different light power intensities and highest photo responsivity and detectivity were determined to be 934.1 A/W and 2.30 × 10 Jones, respectively. Those values are appreciably higher than previous reports for topological insulator based devices. Thus, this work establishes a hybrid system based on topological insulator BiSe nanoflake and Si nanowire as the newest efficient candidate for advanced optoelectronic materials.

Going beyond much cultivated photovoltaic aspects of all inorganic lead halide perovskite, here we explored electron field emission of CsPbX 3 nanorods, where X represents different halides, specifically Cl, Br, and I. Starting with room-temperature preparation of different perovskite nanorods, we examined their electron-emission behavior and found CsPbI 3 as best electron emitter among the synthesized samples, which showed that low work function and high aspect ratio drove the best emission performance. Aspect ratios of the CsPbI 3 nanorods were tailored via alteration of processing temperature. Nanorods prepared at 90 °C possessing maximum aspect ratio delivered a current density of 133 μA/cm 2 at 8 V/μm applied external field. With an expectation of gaining better emission performance from as-synthesized optimized nanorods, reduced graphene oxide (rGO) was further attached to them. Relying on the emission beneficial electronic features of rGO as-prepared CsPbI 3 -rGO composite delivered significantly improved electron emission performance with low turn-on field and high field enhancement value, which are much better than the individual structural blocks. Easy electron passage from the composite as a consequence of work function decrement as well as high field amplification at graphene basal plane supported by one-dimensional CsPbI 3 nanorod renders improvement in field values. Experimentally observed electron emission result is further verified through electrostatic field distribution calculation using ANSYS software. Such results indicated the potential utility of these kinds of perovskite materials in field electron-emission nanodevices.