Tungsten oxide (WO₃) is a wide band gap semiconductor with unintentionally n−doping performance, excellent conductivity, and high electron hall mobility, which is considered as a candidate material for application in optoelectronics. Several reviews on WO₃ and its derivatives for various applications dealing with electrochemical, photoelectrochemical, hybrid photocatalysts, electrochemical energy storage, and gas sensors have appeared recently. Moreover, the nanostructured transition metal oxides have attracted considerable attention in the past decade because of their unique chemical, photochromic, and physical properties leading to numerous other potential applications. Owing to their distinctive photoluminescence (PL), electrochromic and electrical properties, WO₃ nanostructure−based optical and electronic devices application have attracted a wide range of research interests. This review mainly focuses on the up−to−date progress in different advanced strategies from fundamental analysis to improve WO₃ optoelectric, electrochromic, and photochromic properties in the development of tungsten oxide−based advanced devices for optical and electronic applications including photodetectors, light−emitting diodes (LED), PL properties, electrical properties, and optical information storage. This review on the prior findings of WO₃−related optical and electrical devices, as well as concluding remarks and forecasts will help researchers to advance the field of optoelectric applications of nanostructured transition metal oxides.

Tungsten disulfide (WS₂) is a promising material with excellent electrical, magnetic, optical, and mechanical properties. It is regarded as a key candidate for the development of optoelectronic devices due to its high carrier mobility, high absorption coefficient, large exciton binding energy, polarized light emission, high surface-to-volume ratio, and tunable band gap. These properties contribute to its excellent photoluminescence and high anisotropy. These characteristics render WS2 an advantageous material for applications in light-emitting devices, memristors, and numerous other devices. This article primarily reviews the most recent advancements in the field of optoelectronic devices based on two-dimensional (2D) nano-WS₂. A variety of advanced devices have been considered, including light-emitting diodes (LEDs), sensors, field-effect transistors (FETs), photodetectors, field emission devices, and non-volatile memory. This review provides a guide for improving the application of 2D WS₂ through improved methods, such as introducing defects and doping processes. Moreover, it is of great significance for the development of transition-metal oxides in optoelectronic applications.

In this work, a photosensitive (PS) optical fiber-based Mach-Zehnder interferometer (MZI) structure is developed to diagnose the presence of collagen-IV in human bodies. The MZI is fabricated by sequentially splicing the single mode-multimode-photosensitive-multimode single mode (SMPMS) fiber segments. The sensing region in MZI structure is created by partially removing the cladding of photosensitive fiber by using 40% hydrofluoric (HF) acid and depositing the layers of highly reflective metal nanoparticles (NPs) over it. The used NPs are polyvinyl alcohol stabilized silver nanoparticles (PVA-AgNPs), gold nanoparticles (AuNPs), and zinc oxide nanoparticles (ZnO-NPs). The size of AuNPs, PVA-AgNPs, and ZnO-NPs are 10 ± 0.2 nm, ~ 4-5 nm, and <; 50 nm, respectively. In order to avoid the interference of other biomolecules in the detection of collagen-IV, the sensing region is functionalized with a collagenase enzyme. The sensing ability of the probe is ascertained by sensing a wide concentration of collagen solution ranging from 0 ng/ml to 1 μg/ml. It is observed that sensing performance of probe is much better on immobilizing it with PVA-AgNPs and ZnO-NPs.

A semiconducting-semimetallic transition was observed to occur at 12.6 GPa, followed by an orthorhombic to monoclinic structural transition.