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Luminescent nanomaterials are used in everyday life due to their employment in distinct fields of science and technology, like cathode ray tubes (CRTs), flat panel display devices, temperature sensors, lasers, solar-cells, biological imaging, and solid-state lighting but also as carriers for miscellaneous therapeutic drugs. We have prepared dysprosium Dy3+ (0.5 mol %) doped lanthanum phosphate (LaPO4) phosphor by solid state reaction method. The excitation spectra of synthesized phosphor at 595 nm monitoring were composed of broadband and a series of sharp peaks, the strongest excitation peak at 254, 271, and 350 nm. The main emission spectra of samples under 254, 271, and 350 nm excitation are Dy3+ (0.5 mol %) doped LaPO4 phosphor observed at 477 and 573 nm corresponding to blue and yellow color. The broadband emission is the characteristic of the allowed f-h transition of Dy3+ ions. The corresponding emission band is observed due to the (blue emission) 4f9/2→6h15/2, (yellow emission) 4f9/2→6h13/2 transition of Dy3+ ions. All the samples have been characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and photoluminescence (PL) techniques. [ABSTRACT FROM AUTHOR]

The growing generation of waste electrical and electronic equipment (WEEE) in developing countries has attracted increasing attention due to its potential health and environmental impacts and high recycling potentials. For example, along with the rapid economic development, China has been experiencing a sharp increase in the production and use of TV sets and a quick transition from old fashion cathode ray tube (CRT) ones to flat panel display (FPT) ones. Understanding such dynamics would be important for predicting future WEEE generation. In this article, we developed a dynamic (from 1992 to 2040), bottom-up (TV sets by module by material), and stock-driven (using future possession as a driver) material flow analysis model to investigate the amount of metals and plastics embodied in obsolete TV sets in the future. We found that the total generation of obsolete TV sets in China will reach 142 million units by 2040, in which FPD TV sets contribute more after they started to dominate the market after 2009. These growing obsolete TV sets would mean potentially large amount of embodied materials that can be recycled. While most of the embodied precious metals (e.g., gold, silver, and palladium), common metals (e.g., iron, aluminum, zinc, and tin), toxic metals (e.g., mercury, barium, and antimony), and plastics will increase in future, copper and nickel show a first decrease then increase trend, and lead will be gradually phased out in obsolete TV sets. Our results could help inform waste management and recycling strategies and relevant decision makers (e.g., governmental agencies, manufactures, and recyclers) in the TV sets sector in China. Such a stock-driven and bottom-up approach can also be used for other e-waste issues and other countries. [ABSTRACT FROM AUTHOR]

Because of the rapid succession of technological developments, the architecture and material composition of many products used in daily life have drastically changed over the last decades. As a result, well-adjusted recycling technologies need to be developed and installed to cope with these evolutions. This is essential to guarantee continued access to materials and to reduce the ecological impact of our material consumption. However, limited information is currently available on the material composition of arising waste streams and even less on how these waste streams will evolve. Therefore, this paper presents a methodology to forecast trends in the material composition of waste streams. To demonstrate the applicability and value of the proposed methodology, it is applied to forecast the evolution of plastic housing waste from flat panel display (FPD) TVs, FPD monitors, cathode ray tube (CRT) TVs and CRT monitors. The results of the presented forecasts indicate that a wide variety of plastic types and additives, such as flame retardants, are found in housings of similar products. The presented case study demonstrates that the proposed methodology allows the identification of trends in the evolution of the material composition of waste streams. In addition, it is demonstrated that the recycling sector will need to adapt its processes to deal with the increasing complexity of plastics of end-of-life electronic displays while respecting relevant directives. [ABSTRACT FROM AUTHOR]

Nowadays there are several technologies used for flat panel displays (FPDs) and the development of FPDs with enhanced energy efficiency and improved display quality is strongly required. Field emission displays (FEDs) have been considered as one of the most promising next generation flat panel display technologies due to their excellent display performance and low energy consumption. For the development of FEDs, phosphors are irreplaceable components. In the past decade, the study of highly efficient low-voltage cathodoluminescent materials, namely FED phosphors, has become the focus of enhancing energy efficiency and realizing high-quality displays. This review summaries the recent progress in the chemical synthesis and improvement of novel, rare-earth and transition metal ions activated inorganic cathodoluminescent materials in powder and thin film forms. The discussion is focused on the modification of morphology, size, surface, composition and conductivity of phosphors and the corresponding effects on their cathodoluminescent properties. Special emphases are given to the selection of host and luminescent centers, the adjustment of emission colors through doping concentration optimization, energy transfer and mono- or co-doping activator ions, the improvement of chromaticity, color stability and color gamut as well as the saturation behavior and the degradation behavior of phosphors under the excitation of a low-voltage electron beam. Finally, the research prospects and future directions of FED phosphors are discussed with recommendations to facilitate the further study of new and highly efficient low-voltage cathodoluminescent materials. [ABSTRACT FROM AUTHOR]