Currently, white light-emitting diodes (WLEDs) are emerging lighting techniques and are highly desirable. These are one of the world’s highest lighting technologies. LEDs have attracted special attention of research society, scholars and society through their benefits and applications. Phosphor-converting light-emitting diodes (PC-LEDs) show immense potential for the future and, in the coming years, it is expected that LEDs will be easily available at a cheaper price with lower energy consumption. Rare earth activated phosphors are an integral and important part of white light generation. In this review, we have studied numerous research papers about phosphor-converted light-emitting diodes (pc-LED). The main objective of this review paper is to analyze inorganic materials that have been synthesized by various methods and are suitable for eco-friendly lighting applications. In this review, we propose the plan and discovery of new LED phosphors from two alternate points of view, i.e., basic crystal structure in various host systems and co-doped activators through energy transfer. The color-tunable properties of rare-earth activated phosphors explain in detail. Numerous color-tunable phosphor materials have been studied and discussed in this review. In addition, utilizations, difficulties and development or improvement of pc-WLEDs will be discussed.
The aim of this study is to prepare thick films of MoO3 with various weight percentages of aluminum dopant and study its gas sensing characteristics. The thick films were prepared on alumina substrate using easily reproducible, cost-effective screen printing method. The films were characterized using XRD, FESEM, EDS and static gas sensing apparatus. The XRD analysis confirmed the presence of Molybdenum trioxide (JCPDS 05-0508) and aluminum (JCPDS 31-0026). The XRD conveyed that aluminum has occupied an interstitial position and got oxidized to alumina. FESEM showcased the characteristic lamellar structure of MoO3 with voids. The EDS data showed that films were having oxygen excess and the oxygen vacancies increased with aluminum doping percentage. Resistivity and activation energies decreased first and then increased with dopant (aluminum) percentage. The Al5 films showed a minimum resistivity ([Formula: see text]m) and activation energy (0.19[Formula: see text]eV). The TCR had a negative value for all five films supporting n-type semiconductor behavior of the films. The Al5 films showed 84.3% sensitivity to 1000[Formula: see text]ppm of NO2 gas at 200∘C. Authors discussed adsorption-desorption based gas sensing mechanism in detail. Research work tested efficient NO2 gas sensor using aluminum-doped MoO3 thick films.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.