Qualitative Analysis of Magnetic Moment in BaxTiO3 - Ni xFe3- xO4 Nanocomposite Synthesized by Novel low Temperature Technique

A novel low temperature preparation technique (<500ºC) is employed for synthesizing nanoscale Barium Titanate -Nickel ferrite composites, where the particle size is controllable. Two different ratios of hard and soft site composites (BTO-NFO 80:20, BTO-NFO 70:30) are synthesized and characterized to study their unique structural, morphological and magnetic properties. The structural refinement studies using XRD data showed 43 % of hard phase (anorthic structure) and 57% of soft phase (Cubic Structure) for BTO-NFO 80:20 and similarly 76% of hard phase and 24% of soft phase in the BTO-NFO 70:30 composite respectively. The SEM and EDAX are used to identify smaller particles of 10 nm using histogram and their sample purity. The VSM analysis at room temperature shows superparamagnetic behavior within the soft ferro magnet with maximum retentivity 2.39 emu/g and saturation magnetization, 10.71 emu/g stating that the composites can be used for various biological applications like drug delivery, hyperthermia, MRI, etc. The ratio Mr/Ms is much less than 0.5, which states that multidomain grains or single domains are formed and the particle interaction is by magneto-static interaction confirming its superparamagnetic nature.

Subtractive Low-Temperature Preparation Route for Porous SiO2 Used for the Catalyst-Assisted Growth of ZnO Field Emitters

The possibility to gradually increase the porosity of thin films facilitates a variety of applications, such as anti-reflective coatings, diffusion membranes, and the herein investigated tailored nanostructuring of a substrate for subsequent self-assembly processes. A low-temperature (<160 °C) preparation route for porous silicon oxide (porSiO2) thin films with porosities of about 60% and effective refractive indices down to 1.20 is tailored for bulk as well as free-standing membranes. Subsequently, both substrate types are successfully employed for the catalyst-assisted growth of nanowire-like zinc oxide (ZnO) field emitters by metal organic chemical vapor deposition. ZnO nanowires can be grown with a large aspect ratio and exhibit a good thermal and chemical stability, which makes them excellent candidates for field emitter arrays. We present a method that allows for the direct synthesis of nanowire-like ZnO field emitters on free-standing membranes using a porSiO2 template. Besides the application of porSiO2 for the catalyst-assisted growth of nanostructures and their use as field emission devices, the herein presented general synthesis route for the preparation of low refractive index films on other than bulk substrates—such as on free-standing, ultra-thin membranes—may pave the way for the employment of porSiO2 in micro-electro-mechanical systems.

Low-temperature-processed metal oxide electron transport layers for efficient planar perovskite solar cells

As a promising photovoltaic technology, perovskite solar cells (pero-SCs) have developed rapidly over the past few years and the highest power conversion efficiency is beyond 25%. Nowadays, the planar structure is universally popular in pero-SCs due to the simple processing technology and low-temperature preparation. Electron transport layer (ETL) is verified to play a vital role in the device performance of planar pero-SCs. Particularly, the metal oxide (MO) ETL with low-cost, superb versatility, and excellent optoelectronic properties has been widely studied. This review mainly focuses on recent developments in the use of low-temperature-processed MO ETLs for planar pero-SCs. The optical and electronic properties of widely used MO materials of TiO2, ZnO, and SnO2, as well as the optimizations of these MO ETLs are briefly introduced. The commonly used methods for depositing MO ETLs are also discussed. Then, the applications of different MO ETLs on pero-SCs are reviewed. Finally, the challenge and future research of MO-based ETLs toward practical application of efficient planar pero-SCs are proposed. Graphical abstract