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Spectroscopic Analyses for Surface Characterization of Electrospun Fibers
Published in K.M. Praveen, Rony Thomas Murickan, Jobin Joy, Hanna J. Maria, Jozef T. Haponiuk, Sabu Thomas, Electrospun Nanofibers from Bioresources for High-Performance Applications, 2023
Fluorescence spectroscopy is a complimentary spectroscopic technique to UV-Visible spectroscopy. This spectroscopic technique is used to identify the emission of the polymer(s) if fluorescent in nature. Fluorescence is a type of luminescence where the wavelength of emitted radiation is higher than the wavelength of the absorbed radiation. If the two radiations are of the same wavelength, it is called resonance radiation (Lakowicz, J. R. et al., 1985 and PerkinElmer Ltd, 2000).
3 Nanoparticles
Published in Odireleng Martin Ntwaeaborwa, Luminescent Nanomaterials, 2022
S.J. Mofokeng, F.V. Molefe, L.L. Noto, M.S. Dhlamini
Luminescence is a phenomenon where light emission is produced from electron transitions when excited electrons de-excite to a ground state, radiatively [1]. There are various types of luminescence phenomena such as bioluminescence, phosphorescence, cathodoluminescence, and thermoluminescence, just to mention a few [2]. Bioluminescence is displayed by living organisms, like fireflies, glow-worms, and certain sea bacteria [3]. Phosphorescence and cathodoluminescence occur when a luminescent compound is irradiated with a photon and an electron beam (Fig. 9.1), respectively. Thermoluminescence occurs as a result of electron stimulation by thermal energy from electron trapping centres to a luminescent centre [1]. Figure 9.1 illustrates the luminescence phenomenon, where a luminescent compound is irradiated with an electron beam or a photon beam, which brings about electron excitation from the ground state to an excited state, from where they will de-excite radiatively back to the ground state.
Borate Phosphor
Published in S. K. Omanwar, R. P. Sonekar, N. S. Bajaj, Borate Phosphors, 2022
Though a good amount of work has been done to study ML and LL in inorganic salts like alkali halides, some sulphides like ZnS, borates like MCa4O(BO3)3 (M = Gd, La, Y), aluminates like SrAl2O4, organic materials like saccharides and amino acids and silicates like Ca2MgSi2O7: Eu, Dy, these aren’t sufficient to develop any device using these materials for continuous use in practical fields. It is the need of the hour to intensify the research both in the manufacturing and application areas that will use ML and LL phenomena as a tool. The advancement in information technology, nuclear technology, space technology and health sector and food industry have opened new application areas for using luminescence as a detector. The need of sustainable devices in various atmospheres with long-lasting luminescence have created new areas of research. Most of the applications in the past are directly or indirectly related to detection of radiation dose of gamma or X-rays. Thus, the focus was limited: to synthesise a material whose luminescence intensity depends on various parameters related to radiation dose and the material properties. The luminescence output is also less. That makes these materials restrictive in many fields. Efforts should be taken to increase the luminescence output without fading effect.
Characterization and experimental investigation of rheological behavior of oxide nanolubricants
Published in Particulate Science and Technology, 2021
Harsh Gupta, Santosh Kumar Rai, Piyush Kuchhal, Gagan Anand
Photoluminescence occurs when a sample excited by absorbing photons emits photons at different wavelength when returning to its original energy level. This is a nondestructive process in which light directed on to a sample absorbs energy, this is termed as photo excitation. Luminescence is one of the ways by which the absorbed energy is dissipated, i.e., through the emission of light. In the case of photo excitation, the luminescence is termed as photoluminescence. This is a valuable tool to characterize nanoparticles. The device used to conduct this test in this experiment is PerkinElmer LS 45 Fluorescence Spectrometer (PerkinElmer, Waltham, MA). It uses a Xenon source for excitation. The data of dissipated energy for different wavelength was obtained from the Win Lab software. The range of wavelengths for this device is from 200 to 800 nm.
Selective fluorescence sensing and photocatalytic properties of a silver(I)-based metal-organic framework based on 9,10-anthraquinone-1,5-dicarboxylic acid and 4,4'-bipyridine ligands
Published in Inorganic and Nano-Metal Chemistry, 2020
Jun-Jie Wang, Yan Chen, Pan-Pan Si, Rui-Yang Fan, Jie Yang, Ya-Ya Pan, Shan-Shan Zhao, Yun-Feng Shi
Nowadays, toxic organic small molecules and harmful pollutants have been demonstrated to adversely affect people’s health.[4] Thus, it is imperative that such pollutants in wastewater are detected and rapidly degraded. Among all the detection technologies, luminescence methods have attracted much interest due to their distinguishing advantages, such as short response time, high sensitivity, simplicity, and suitability for use either in the solid phase or in solution.[5] Meanwhile, the photocatalytic degradation of organic pollutants has been intensively investigated as an effective technique offering high efficiency, simplicity, and good reproducibility.[6] MOFs have already been used to detect small organic molecules and degrade organic pollutants.[7] Generally, the selectivity and sensitivity of the luminescence detection is mainly dependent on the electron density of the MOFs as well as their ability to donate electrons.[8] Thus, MOFs constructed from electron-rich aromatic fluorescent ligands are excellent candidates for fluorescent sensors.[9] With this in mind, we initiate a strategy of utilizing mixed aromatic moieties as fluorescent tags to tune the sensitivity and selectivity of MOFs for detecting small organic molecules and degrading organic pollutants.