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The purpose of this study is to develop luminescence sensors for the detection of nitroaromatic compounds (NACs) and metal ions to protect human health and prevent environmental pollution.

The composition and morphology of Eu-metal-organic frameworks (MOF) (1) were well characterized by powder X-ray diffraction, elemental analyses, Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy and scanning electron microscopy. The emission spectrum displays that 1 has significant characteristic emission bands of Eu(III) ions. The authors further investigated the fluorescence sensing performances of 1 to NACs and metal ions.

The results show that Eu-MOF (1) exhibits significant fluorescence quenching effect toward p-nitroaniline and Fe³⁺ ions with good stability and recyclability. This means that 1 can be used as a multifunctional sensing material for the detection of p-nitroaniline and Fe³⁺ ions.

The authors have successfully synthesized a fluorescence Eu-based sensing material under hydrothermal conditions. In addition, the fluorescence property and sensing performances for detecting NACs and metal ions were studied. The results suggest that 1 has highly selective fluorescence quenching toward p-nitroaniline and Fe³⁺ ions with not only high sensitivity and selectivity but also excellent stability and recyclability. Furthermore, this study has confirmed that the multifunctional MOF material is very useful in environment pollutants’ detection and monitoring.

The purpose of this paper is to investigate three preparation processes and the photoluminescent (PL) properties of PbS/poly(p‐phenylene vinylene) (PPV) composite fibres.

By the combination of electrospinning technology, chemical vapour deposition and chemical liquid deposition, PbS/PPV composite nanofibres were prepared by three simple methods. The morphologies of the fibres and the PL properties were researched with the transmission electron microscopy (TEM) and the eclipse fluorescence spectrophotometer.

By different synthetic methods, the dispersion morphologies of PbS nanoparticles and the PL properties of their respective PbS/PPV composite fibres were different. Moreover, the effects of PbS nanoparticles on the luminescence quenching of the PPV were observed in all the synthesised PbS/PPV composite fibres, respectively.

The dispersion morphologies of PbS nanoparticles were not uniform enough.

A new method was used for preparing nanoparticles/polymer composite fibres.

The combination of electrospinning technology and chemical liquid deposition was used for the first time to fabricate the sulfide/polymer composite fibres. In addition, we hope that the results obtained here will provide some useful evidences for the interaction mechanism between IV‐VI group semiconductors and conjugated polymers, and the prepared composite fibres will have applications in the nano‐optoelectronic field.

Polymeric nanocomposite films from PEDOT and MEH-PPV embedded with surface modified TiO₂ nanoparticles were prepared, respectively for the hole transport layer (HTL) and emission layer (EL) in Organic Light Emitting Diodes (OLED). The composite of MEH-PPV + nc-TiO₂ was used for Organic Solar Cells (OCS). The results from the characterization of the properties of the nanocomposites and devices showed that electrical (I-V characteristics) and spectroscopic (photoluminescent) properties of the conjugate polymers were enhanced due to the incorporation of nc-TiO₂ in the polymers. The OLEDs made from the nanocomposite films would exhibit a larger photonic efficiency and a longer lasting life. For the OSC made from MEH-PPV + nc-TiO₂ composite, the fill factor (FF) reached a value as high as 0.34. Under illumination of light with a power density of 50 mW/cm², the photoelectrical conversion efficiency (PEC) was found to be of 0.15% corresponding to an open circuit voltage V_OC = 1.15 V and a short-cut circuit current density J_SC = 0.125 mA/cm².

This paper aims to describe the techniques used in industrial optical chemical sensors and to consider future prospects.

This paper discusses the techniques and technologies used in today's optical chemical sensors. It highlights their limitations and considers briefly certain new technological developments.

This paper shows that techniques such as wet reagent‐aided photometry, UV absorption, spectroscopy and UV fluorescence satisfy a range of industrial chemical sensing applications and that optode technology is making limited commercial inroads. It identifies the need for inexpensive, wet reagent‐free chemical sensors and suggests that both solid‐state electrodes and lab‐on‐a‐chip devices may ultimately resolve this issue.

This paper provides a technical insight into the state of optical chemical sensing and illustrates that generic families of inexpensive chemical sensors are yet to be developed.

The purpose of this paper is to review the applications of commercially available fibre optic sensors (FOSs) and consider the reasons for their use.

Following a short introduction, the paper discusses the applications of FOSs for physical variables, gases and chemical compounds and identifies the reasons for their use.

It is shown that, following over three decades of research, FOSs are employed in many physical sensing uses where particular, application‐specific features confer significant user benefits. They are employed to a far lesser extent to monitor gases and chemical compounds, where the intrinsic features of the technology are of less benefit.

This paper provides an account of the applications of FOSs that have emerged since their development in the 1970s.

Globalization has increased the consumer's demand for safe and quality foods. To make food available to consumers from farm to fork, packaging plays a crucial role. The objective of packaging is to shield the foodstuff from degrading and to serve as the medium of communication between the processing industry and the consumers. Conventionally, several materials are used in the packaging such as laminates, plastics, glass, metal, etc., but with the advent of technology, newer and novel smart packaging technologies have entered this field. Smart packaging in the form of active and intelligent packaging not only acts as a barrier to external influences but also prevents internal deterioration. Oxygen scavengers, moisture controllers, antioxidants, CO₂ absorber/emitter, antimicrobial agents, etc., are some of the vital active packaging systems. On the other hand, an intelligent packaging system contains internal or external indicators and sensors that monitor the condition of packed food and gives information about its quality during storage and transportation. It seems that these interventions in packaging have very positive effects on the whole industry, but it is observed that this advancement in the packaging has also raised questions about its disposal. To overcome this issue, industries have started using smart packaging design along with the sustainable packaging trend. Communication with the recycling bodies at the time of development will ensure the smart packaging fit to be recycled. Considering such standards for smart packaging will not only create a healthy bond between industries and consumers but will also help in sustainable development. This chapter mainly focuses on the advancement of the packaging system associated with the agri-food sector. It also discusses how the implementation of these technological advancements will help the industries toward sustainable development.

There is a strong inducement to develop new inorganic materials to substitute the current industrial pigments, which are known for their poor ultraviolet absorbent and low photoluminescence (PL) properties. The purpose of this paper is to invent a better rare-earth-based pigment material as a spectral modifier with good luminescence properties to enhance the spectral response for photovoltaic panel application.

Different phosphor samples made of nano-calcium carbonate (CaCO₃) with varied wt.% of the dopant Dysprosium doped calcium borophosphate (CBP/Dy) as (W0 – 0%, W1 – 3,85%, W2 – 7.41%, W3 –10.71% and W4 –13.79%) were prepared via the solid-state diffusion method at 600 °C for 6 h using a muffle furnace. The structural, morphological and luminescence properties of the CaCO₃:CBP/Dy powder samples were examined using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and PL test.

The XRD, SEM and FTIR results verified the crystalline formation, morphological behaviour and vibration bonds of synthesized CBP/Dy-doped CaCO₃ powder samples. XRD pattern revealed that the synthesized powder samples exhibit crystalline structured materials, and SEM results showed irregular shape and porous-like structured morphologies. FTIR spectrum shows prominent bands at 712, 874 and 1,404 cm⁻¹, corresponding to asymmetric stretching vibrations of CO3²⁻ groups and out-of-plane bending. PL characterization of CBP/Dy-doped CaCO₃ (sample W) shows emission at 427 nm (λmax) under the excitation of 358 nm. The intensity of PL emission spectra drops due to the concentration quenching effect, while the maximum PL intensity is observed in the W3 phosphor powder system.

This phosphor powder is expected to find out the potential application such as a spectral modifier which is applied to match the energy of photons with solar cell bandgap to improve spectral absorption and lead to better efficiency.

The introduction of a nano-CaCO₃:CBP/Dy hybrid powder system with good luminescence properties to be used as spectral modifiers for solar cell application has been synthesized in the lab, which is a novel attempt.

In general, lighting application, white light emitting diode (LED) usually exposed to an extreme operating temperature of above 90°C. It is well-known that luminous efficacy and spectral characteristic of white LED are dependent on the temperature, causing thermal effects on luminous efficacy and color shift of white LED become a critical application checkpoint to be addressed by white LED manufactures. Thus, the purpose of this paper is to minimize the thermal stability issue affecting white LED luminescence during operation by introducing phosphor sedimentation process.

The LED samples were assembled and sent for centrifugation with 0, 5 and 10 revolutions per second (rps), respectively, during phosphor sedimentation process. Luminescence properties of these LED samples were then characterized at a varying temperature to investigate the effect of phosphor sedimentation on the luminescence stability of LED samples. The LED samples were also cross-sectioned and analyzed to understand the phosphor sedimentation mechanism. Computational fluid dynamics (CFD) was applied to study the temperature distribution of the non-phosphor sediment (NPS) and phosphor sediment (PS) LED during operation to validate the hypotheses based on experimental data.

Experimental results show that the luminous intensity of PS LED samples degrades less significant at high temperature. The experimental results also show that the color coordinate for PS LED samples is more stable and is less blue-shifted than NPS LED samples as the temperature increased. These are because the heat generated by phosphor particles during operation can be dissipated effectively throughout a high thermal conductivity substrate after phosphor sedimentation. Thus, the phosphor temperature of PS LED is lower than NPS LED during operation as validated with the thermal simulation.

The study of this paper is applicable as a reference for industries who intend to resolve the thermal stability of white LED during operation. The luminescence properties changes as a function of the temperature study in this paper can be used to predict the application performances of white LED accurately. Apart from that, the analysis method of temperature distribution using CFD simulations can be extended by other CFD users in the future.

Implementation of phosphor sedimentation to reduce thermal instability issue of white LED has yet to be reported on previous studies. Most literature just studied the thermal instability issue of either assembled LED or raw material, without suggesting any solution to tackle the issue.

To evaluate the effect of flux, activator and co‐activator on solid state synthesis of SrAl₂O₄: Eu^2 +, Dy^3 + phosphor, where boric oxide, europium oxide and dispersium oxide were used, respectively.

To optimise synthesis condition of long lasting phosphorescence SrAl₂O₄ phosphor, boric oxide was used as a flux. To improve relative intensity of SrAl₂O₄: Eu^2 + phosphor, the critical concentration of Eu^2 + was determined. The effect of various concentration of co‐activator on afterglow properties, the effect of Dy^3 + ion on the emission and excitation spectra were examined.

The SrAl₂O₄: Eu^2 +, Dy^3 + phosphor powders have been synthesised by solid state reaction method. The result of XRD patterns indicated that, addition of 5 mol% B₂O₃ enhanced the formation of SrAl₂O₄ at 1,200°C. Investigation on the variation of emission intensity of different phosphors containing different amounts of Eu^2 + revealed that after 6 mol% of Eu^2 + concentration, quenching process occurred. Dy^3 + formed trap levels and results demonstrated that increasing concentration of Dy^3 + up to 5 mol% reduced the relative intensity and increased the decay time.

Using B₂O₃ as a flux and solid state reaction method for preparation of this phosphor is in good agreement with industrial production and make it economic, because of reduced sintering temperature.

This study aims to develop a new simple and sensitive method for the microextraction of trace levels of lead in environmental samples. It is based on the use of ionic liquids based dispersive liquid–liquid microextraction (IL–DLLME) before spectrofluorometry.

Cadmium sulphide quantum dots have been synthesised using thioglycolic acid as capping agent through a one-step process with stability and excellent water-solubility, and have strong affinity for lead (Pb). This probe is based on the fluorescence quenching effect of functionalised cadmium sulphide quantum dots.

Factors affecting the extraction efficiency and fluorescence quenching of metals, such as the amount of ionic liquid, amount of metanol, microextraction and centrifugation time, volume of quantum dots and buffer pH, were investigated. Under optimum conditions, the calibration graph was linear in the range of 0.01-3 µg.L-1, with the detection limit of 0.004 µg.L-1 for Pb2+. The relative standard deviation (RSD%, n = 5) of 5.4 per cent at 1 µg.L-1 of Pb2+ was obtained.

This method for pre-concentration of the Pb ions by dispersive liquid–liquid microextraction is novel and could be used for various applications in the synthesis of a wide variety of determination of fluorescence quenching of cadmium sulphide quantum dots.