About this Research Topic
The lanthanide-based materials are highly photoluminescent materials. They cover a broad range of emission bands from the ultraviolet (UV) and visible (vis) to the near infrared (NIR) regions. These materials are chemically and thermally stable for longer time span. The lanthanide ions have ladder-like energy levels and many of them are meta-stable (i.e. long-lived levels). They show very fascinating optical properties for the upconversion (UC) and downconversion (DC) processes, which contribute significantly for the conversion of light from the low energy to high energy and vice-versa. Actually, the lanthanide-based DC materials convert a high energy photon into the low energy photons. However, the two or more low energy photons are converted into the high energy photons by the lanthanide-based UC materials. The optical properties of these materials are still to be investigated with the help of various optical characterization tools in order to understand the basics of different mechanisms in the excited states. The researchers are mainly focused on the development of various types of photoluminescent materials so that they could find their applications in different technological fields, such as display devices, blue, green and red emitting materials, light emitting diodes (LEDs), solid state lighting, phosphor-converted LEDs (pc-LEDs), white LEDs, dosimetry, temperature sensing, bio-imaging, etc.
Temperature sensing is basically a unique property of the lanthanide ion, which is based on the fluorescence intensity ratio (FIR) of the two emitting levels. These levels may be either thermally coupled (TC) or non-thermally coupled (NTC) type. In both the cases, the emission intensity arising from one level increases while that of the other is found to decrease on increasing the external temperature of the sample and vice-versa. This affects the lattice vibration of the host lattice, which causes to shift some of the population of the excited ions from one level to the other level. The plot between FIR-based sensitivity and external temperature is a measure of temperature sensing. The lanthanide-based materials are also useful for bio-imaging purposes.
The optical properties of lanthanide-based materials are still to be investigated with the help of various optical characterization tools in order to understand the basics of different mechanisms in the excited states.
This collection aims to focus on the synthesis and characterization of different types of lanthanide-based materials, such as glass, glass-ceramics, ceramics, phosphor, nano-phosphor, composites, etc. This collection welcomes the original articles as well as the review articles related to the synthesis and characterization of different types of lanthanide-based materials along with their applications in different technological aspects.
Keywords: Lanthanide ions, Synthesis, Characterisation, Optical properties, Applications
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