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Polyvinylcarbazole was discovered by the chemists Walter Reppe (1892-1969), Ernst Keyssner and Eugen Dorrer and patented by I.G. Farben in the USA in 1937. [4] [1] PVK was the first polymer whose photoconductivity was known.
Upon exposure to γ-irradiation, N-vinylcarbazole undergoes solid-state polymerisation. [ 5 ] It is produced by the vinylation of carbazole with acetylene in the presence of base.
Phosphorescence is a type of photoluminescence related to fluorescence. When exposed to light (radiation) of a shorter wavelength, a phosphorescent substance will glow, absorbing the light and reemitting it at a longer wavelength. Unlike fluorescence, a phosphorescent material does not immediately reemit the radiation it absorbs.
Photoluminescence (abbreviated as PL) is light emission from any form of matter after the absorption of photons (electromagnetic radiation). [1] It is one of many forms of luminescence (light emission) and is initiated by photoexcitation (i.e. photons that excite electrons to a higher energy level in an atom), hence the prefix photo- . [ 2 ]
Photoluminescence excitation (abbreviated PLE) is a specific type of photoluminescence and concerns the interaction between electromagnetic radiation and matter.It is used in spectroscopic measurements where the frequency of the excitation light is varied, and the luminescence is monitored at the typical emission frequency of the material being studied.
Since the early applications of luminescence dating in the 1960/1970s, the field has received growing attention in the scientific community, with more than 3500 publications per year and >200 laboratories across the globe in 2020. [7] Types of luminescence dating techniques with their stimulation and resetting event.
PCB warning label on a power transformer known to contain PCBs. Polychlorinated biphenyls (PCBs) are organochlorine compounds with the formula C 12 H 10−x Cl x; they were once widely used in the manufacture of carbonless copy paper, as heat transfer fluids, and as dielectric and coolant fluids for electrical equipment. [2]
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