Hybrid Phosphor Materials

Electric lighting has become a significant part of human daily life, accounting for approximately 15% of global power consumption. Among various illumination, white light-emitting diodes (WLEDs) have become a major research focus of the industry due to their long lifespan and high energy efficiency. Current commercial WLEDs are fabricated mainly through utilizing blue LEDs with phosphor coatings. Under the environment of energy-saving emission reduction, according to the haitz’s law of LED industry, LED will follow the development process of aiming high brightness and low cost. Thus, exploring new phosphors for lightings, compatible with the cost reduce, is highly desired. Metal halide perovskite phosphors have attracted wide attention due to their outstanding luminescence feature and low-cost solution-processing. In this chapter, we first introduced perovskite phosphors of different colors, including three primary colors (blue, green, red), and other colors (e.g. white, yellow and orange). Then, we further summarized the stability improvement strategies of through hybrizing perovskite phosphors with inorganic materials, organic molecules and polymer, and the non-luminous perovskites and luminous perovskites. Finally, we presented some strategies of perovskite phosphor applications in WLEDs, such as by combining GaN chip with three-primary-color perovskite phosphors, through energy transfer in one perovskite, and by doping ions in perovskites.

1Mechanoluminescence is a well-known phenomenon of light emission induced by deformation when certain solids suffer external mechanical stress. Mechano-luminescent materials which could convert mechanical energy directly into photons have attracted increasing attention in recent years for their wide potential applications in stress sensing and imaging, structural damage monitoring, wearable illuminating devices, self-powered display, mechanical energy collection and conversion, bio-imaging, and photodynamic therapy. Great progress has been made in developing novel materials with strong mechanoluminescence emission and their applications.

Phosphors constitute the most important component of organic light emitting diodes (OLEDs), therefore, there has been continuous development in this field. Molecular hybrid phosphors are basically transition metal complexes that are formed by complexation of heavy metal ion with suitable ligand system. The cyclometalated transition metal complexes constitute the major chunk of molecular hybrid phosphors. This chapter covers molecular hybrid phosphors based on complexes of heavy metals such as gold, iridium, platinum, rhodium and ruthenium.

The lighting industry is largely revolutionized with the advent of Light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs). The white light phosphors are being designed with an aim to get better colour stability. The process involved in the synthesis should be easy applicable to large scale as well. This chapter summarizes extensively explored popular classes of organic–inorganic hybrid phosphors. These include: coordination compounds obtained from small organic molecules, organically coated nanoparticles, hybrid-carbon phosphors, organic polymer-based hybrids. The limitations of currently used phosphors for white-light emission and the possible remedies are discussed.

The present chapter describes phosphorus-based phosphor compounds focused especially, on their synthesis, properties and applications. One of the main properties of phosphor materials is the photoluminescence. The phosphorus-based phosphors have already many applications in medicine (imaging techniques) and also in high power light-emitting diodes (LEDs) as light source for illumination or plant growth, field emission displays (FEDs), cathode ray tubes (CRT), X-ray detectors, projection televisions (PTV), fluorescent lamps, laser technologies, plasma display panels (PDP), ultraviolet-visible photocatalysts or temperature sensing, and so on. The LEDs technology significantly reduced the energy consumption for electric lighting. By using novel phosphor compounds, high emission-efficient fields in displays and UV devices are already produced. On the last two decades the importance and therefore the interest for those compounds increased significantly. While most of them are synthesized via the classic solid-state method, in the last years other synthesis routes developed also, as for instance the combustion method, the sol–gel method, the precipitation method, the hydrothermal method, ultrasonic spray pyrolysis, extraction pyrolytic technique, hydrolysis, and decomposition.

Graphite and its derivatives are at the forefront of scientific curiosity. Graphene structure considered to be one atom thick two-dimensional honeycomb layer of sp² carbon atoms.

Phosphors are special types of compounds which emit lights when exposed to visible light, ultraviolet radiation or electron beam. In general, these compounds are prepared from inorganic transition metal or rare earth compounds. The radiation causes movement of its valence electron to the conduction or exciton band leaving behind a hole in the valence band. The electron–hole pairs moves to the impurities in the crystal of the phosphor which rapidly de-excite by emitting light. The inhomogeneity in the crystal structure of phosphor is created by addition of the impurities or dopants which is also called activator. Accordingly, a phosphor consists of a host which is oxides, nitrides, sulfides, halides, silicates or selenides of Zn, Cd, Mn, Al, Si or different rare earth metals and an activator metal such as Cu or Ag activated ZnS or Bi activated CaS phosphor. Apart from inorganic phosphors, more energy efficient phosphors for lighting and other optoelectronic applications are prepared from metal–organic frameworks (MOF) or coordination polymers. MOF consists of single metal ions or clusters of metal ions linked by organic ligands having multiple binding sites to form extended network structures. However, the inorganic or MOF based phosphors have several drawbacks like limited resources, high toxicity and also high cost. In contrast to inorganic or MOF based phosphors, metal-free small organic molecules or polymer based room temperature phosphors (RTP) are environment friendly and easy to process. These two types of RTPs are characterized by its long-lived triplet excitons and larger Stokes shift. However, easy processing, good flexibility and stretching ability, low cost, excellent electron mobility and thermal conductivity have made polymer based RTPs more attractive than small organic molecules based RTPs. Thus, Polymer based RTPs are widely used in organic light emitting diodes, solar cells, field effect transistors, memory devices and many other similar applications. The phosphors are prepared by (1) intersystem crossing (ICS) from the lowest excited singlet state (S₁) to a triplet state (T_n) and (2) radiative transition from the lowest excited triplet state (T₁) to the ground state (S₀). The emission from T₁ state is quenched at room temperature under ambient conditions. Accordingly, the challenge to get efficient RTP is to suppress nonradiative decay. Polymers are of high molecular weight with long chains that can cause entanglement and a high degree of rigidity making them ideal candidates to observe phosphorescence from organic lumiphores. In this book chapter synthesis, properties and applications of (1) non-doped and (2) doped polymer based RTPs will be discussed with reference to recent literature with the following possible.

Frequency upconversion hybrid phosphors have many applications in various fields. In this chapter, biological applications such as biomolecule sensing, intra-cellular pH sensing, micro-volume temperature sensing, optical coherence tomography (OCT) imaging, photodynamic & photothermal therapy, etc., are discussed in detail. Also, various synthesis methodologies are discussed.

Hybrid phosphors have gained large interest in the field of biomedical systems owing to their excellent physicochemical features. The potentiality of hybrid phosphors also lies in gathering favourable features of varied nanoforms in a single construct. An advantage of polymer as one of the components as host material for luminescent phosphors is their simple method of preparation, superior mechanical properties, higher flexibility and lighter density. The polymer films are prepared by melt casting or spin coating and materials of any desirable size or shape can be prepared from polymers. Moreover, manufacturing of polymers is cheaper and the energy consumption of making polymers is much lower. Different types of optically transparent polymers can easily be incorporated with phosphors. In a hybrid matrix it has higher thermal stability and luminescence output. Besides, being an agent for in-vivo imaging, hybrid phosphor based fluorescent materials also demonstrate several advantages for use in bioassay and therapy. Amongst different phosphor-based nanomaterials, upconversion phosphors are potential optical contrast agents for uses in biomedical appliance due to their long emission lifetime, sharp emission peaks, and their photostability. In this chapter, a comprehensive overview on hybrid upconversion phosphor is discussed with the basic conceptions that include the mechanisms for the illustration of different fluorescent behaviours, the different methods applied for the preparation of these phosphors, and finally the uses of these materials in biological arena. In addition, new trends in these type of materials are summarized with future perspectives.

You might be reading the article on a computer screen or on a book. On both the cases, light is required, be it the light on screen or the light required for reading. You might go to a supermarket and now you may not need to stay in large ques, thanks to the modern laser scanners and barcode readers. You might be browsing the internet, Thanks to the fibre amplifier in optical cables. When you think of hybrid phosphor materials in daily life, you will be able to see many devices helping you directly or indirectly in many ways. This chapter gives a short insight into the Luminescent thin films, Polymer optical amplifiers and LEDs.

Sensing of analyte molecules via monitoring the turn-on fluorescence produced by magneto-luminescent and plasmonic nanoassembly for the analyte, when present in aqueous medium is depicted in this study. Donor–acceptor FRET phenomenon first provides a turn-off fluorescence followed by a turn-on fluorescence exhibited as a consequence of meisenheimer complex formation between the functionalized AuNp of the nanoassembly and nitro groups of the analyte. Here, UV–Visible, Photoluminescence, TCSPC, TEM, DLS, zeta potential, and FT-IR analytical techniques were employed for substantiating the observed phenomenon.

Nanoparticles have great potential in the biomedical field owing to its superior properties. Hybrid nanomaterials can be used to perform both diagnostic and therapeutic function by a single system. These materials will have the synergistic beneficial features of the different nanomaterials incorporated. In this chapter, we have categorised the inorganic/organic hybrid nanomaterials which are being developed in the field of biomedical applications. In addition, summarized the most recently reported hybrid nanomaterials, nanoparticles and nanocomposites with their synthesis methods and physicochemical properties. This chapter will summarize the recent advances in the synthesis, design and applications of hybrid nanomaterials in the biomedical field. The applications especially the imaging, drug delivery and cancer therapeutic applications will be highlighted.

The exploration of multifunctional platforms for diverse applications has gained tremendous advancement towards the designing and engineering of numerous versatile materials with many functions combined into nanostructured hybrid systems. Such materials combine the benefits of different components to improve the efficiency, reliability, cost-efficiency, and scalability of the hybrid system. Trivalent lanthanide ion (Ln³⁺)-activated hybrid phosphors are important for designing new multifunctional materials with modulated optical and magnetic properties. Thus, their studies open up new directions in material sciences and related technologies. This chapter presents a broad overview of the recently investigated various Ln³⁺-based inorganic hybrid materials. It covers the hybrids of Ln³⁺-doped inorganic phosphors, including oxides, fluorides, phosphates, vanadates, sulfides, with materials such as (a) semiconductors (TiO₂/ZnO), (b) magnetic nanoparticles (Fe₃O₄), (c) metal/plasmonic nanoparticles (Au/Ag), (d) graphene and its derivatives, (e) quantum dots, (f) polymers, and others. We will present the study of these materials for their modulated luminescence efficiency and respective advantages in the applications of sensing, optical telecommunication, energy harvesting, multimodal imaging, biomedicine, etc. Furthermore, this chapter will also focus on the synthesis methods and approaches, including surface functionalization and modification, core–shell processing, controlled assembly, and the relationship between the composition, structure, and properties. We anticipate that a fusion of distinctive structural aspects and integrated functions will compel researchers to create smart hybrid materials and exploit this opportunity in all three realms of science: physics, chemistry, and biology.