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{{Short description|Luminescent substance}} {{For|the chemical element|phosphorus}} [[File:Luc Viatour phosphore poudre.jpg|thumb|Example of phosphorescence]] [[File:IBM PC 5150.jpg|thumb|[[Monochrome monitor]]]] [[File:CRT Phosphors.jpg|thumb|[[Aperture grille]] CRT phosphors]] A '''phosphor''' is a substance that exhibits the [[optical phenomenon|phenomenon]] of [[luminescence]]; it emits light when exposed to some type of [[radiant energy]]. The term is used both for [[fluorescence|fluorescent]] or [[phosphorescence|phosphorescent]] substances which glow on exposure to [[ultraviolet]] or visible light, and [[cathodoluminescence|cathodoluminescent]] substances which glow when struck by an [[electron beam]] ([[cathode ray]]s) in a [[cathode-ray tube]]. When a phosphor is exposed to radiation, the orbital [[electron]]s in its [[molecule]]s are excited to a higher [[energy level]]; when they return to their former level they emit the energy as light of a certain color. Phosphors can be classified into two categories: [[fluorescent]] substances which emit the energy immediately and stop glowing when the exciting radiation is turned off, and [[Phosphorescence|phosphorescent]] substances which emit the energy after a delay, so they keep glowing after the radiation is turned off, decaying in brightness over a period of milliseconds to days. Fluorescent materials are used in applications in which the phosphor is excited continuously: [[cathode-ray tube]]s (CRT) and plasma video display screens, [[fluoroscopy|fluoroscope screens]], [[fluorescent light]]s, [[Scintillation counter|scintillation sensors]], most white [[Light-emitting diode|LED]]s, and [[luminous paint]]s for [[black light]] art. Phosphorescent materials are used where a persistent light is needed, such as glow-in-the-dark watch faces and aircraft instruments, and in [[radar|radar screen]]s to allow the target 'blips' to remain visible as the radar beam rotates. CRT phosphors were standardized beginning around [[World War II]] and designated by the letter "P" followed by a number. [[Phosphorus]], the light-emitting chemical element for which phosphors are named, emits light due to [[chemiluminescence]], not phosphorescence.<ref>{{cite book|author =Emsley, John|year = 2000|title = The Shocking History of Phosphorus |location= London|publisher =Macmillan|isbn=978-0-330-39005-7}}</ref> ==Light-emission process== [[File:Jablonski Diagram of Fluorescence Only-en.svg|thumb|[[Jablonski diagram]] shows the energy levels in a fluorescing atom in a phosphor. An electron in the phosphor absorbs a high-energy [[photon]] from the applied radiation, exciting it to a higher energy level. After losing some energy in non-radiative transitions, it eventually transitions back to its ground state energy level by fluorescence, emitting a photon of lower energy in the visible light region.]] The scintillation process in inorganic materials is due to the [[electronic band structure]] found in the [[crystal]]s. An incoming particle can excite an electron from the [[valence band]] to either the [[conduction band]] or the [[exciton]] band (located just below the conduction band and separated from the valence band by an [[energy gap]]). This leaves an associated [[electron hole|hole]] behind, in the valence band. Impurities create electronic levels in the [[forbidden gap]]. The excitons are loosely bound [[electronβhole pair]]s that wander through the [[crystal lattice]] until they are captured as a whole by impurity centers. They then rapidly de-excite by emitting scintillation light (fast component). In the conduction band, electrons are independent of their associated holes. Those electrons and holes are captured successively by impurity centers exciting certain [[metastable state]]s not accessible to the excitons. The delayed de-excitation of those metastable impurity states, slowed by reliance on the low-probability [[forbidden mechanism]], again results in light emission (slow component). In the case of inorganic [[scintillator]]s, the activator impurities are typically chosen so that the emitted light is in the visible range or [[near ultraviolet|near-UV]], where [[photomultiplier]]s are effective. Phosphors are often [[transition-metal]] compounds or [[rare-earth]] compounds of various types. In inorganic phosphors, these inhomogeneities in the crystal structure are created usually by addition of a trace amount of [[dopant]]s, impurities called ''[[activator (phosphor)|activators]]''. (In rare cases [[dislocation]]s or other [[crystal defect]]s can play the role of the impurity.) The wavelength emitted by the emission center is dependent on the atom itself and on the surrounding crystal structure. ==Materials== Phosphors are usually made from a suitable host material with an added [[activator (phosphor)|activator]]. The best known type is a copper-activated [[Zinc sulfide|zinc sulfide (ZnS)]] and the [[silver]]-activated zinc sulfide (''zinc sulfide [[silver]]''). The host materials are typically [[oxide]]s, [[nitride]]s and oxynitrides,<ref>{{cite journal| title =Silicon-based oxynitride and nitride phosphors for white LEDsβA review|journal = Sci. Technol. Adv. Mater. |volume =8| year =2007|page = 588|doi= 10.1016/j.stam.2007.08.005|author =Xie, Rong-Jun| first2 =Naoto| last2 =Hirosaki|bibcode = 2007STAdM...8..588X| issue =7β8 |doi-access =free}}{{open access}}</ref> [[sulfide]]s, [[selenide]]s, [[halide]]s or [[silicate]]s of [[zinc]], [[cadmium]], [[manganese]], [[aluminium]], [[silicon]], or various [[rare-earth metal]]s. The activators prolong the emission time (afterglow). In turn, other materials (such as [[nickel]]) can be used to quench the afterglow and shorten the decay part of the phosphor emission characteristics. Many phosphor powders are produced in low-temperature processes, such as [[sol-gel]], and usually require post-annealing at temperatures of ~1000 Β°C, which is undesirable for many applications. However, proper optimization of the growth process allows manufacturers to avoid the annealing.<ref>{{cite journal| title =Fine yellow Ξ±-SiAlON:Eu phosphors for white LEDs prepared by the gas-reductionβnitridation method|journal = Sci. Technol. Adv. Mater.|volume = 8| year =2007|page =601|doi = 10.1016/j.stam.2007.09.003|author =Li, Hui-Li| first2 =Naoto| first3 =Rong-Jun| first4 =Takayuki| first5 =Mamoru| last2 =Hirosaki| last3 =Xie| last4 =Suehiro| last5 =Mitomo|bibcode = 2007STAdM...8..601L| issue =7β8 | doi-access =free}}{{open access}}</ref> Phosphors used for [[fluorescent lamp]]s require a multi-step production process, with details that vary depending on the particular phosphor. Bulk material must be milled to obtain a desired particle size range, since large particles produce a poor-quality lamp coating, and small particles produce less light and degrade more quickly. During the [[pottery firing|firing]] of the phosphor, process conditions must be controlled to prevent oxidation of the phosphor activators or [[contamination]] from the process vessels. After milling, the phosphor may be washed to remove minor excess of activator elements. Volatile elements must not be allowed to escape during processing. Lamp manufacturers have changed compositions of phosphors to eliminate some toxic elements formerly used, such as [[beryllium]], [[cadmium]], or [[thallium]].<ref>Kane, Raymond and Sell, Heinz (2001) ''Revolution in lamps: a chronicle of 50 years of progress'', 2nd ed. The Fairmont Press. {{ISBN|0-88173-378-4}}. Chapter 5 extensively discusses history, application and manufacturing of phosphors for lamps.</ref> The commonly quoted parameters for phosphors are the [[wavelength]] of emission maximum (in nanometers, or alternatively [[color temperature]] in [[kelvin]]s for white blends), the peak width (in [[nanometers]] at 50% of intensity), and decay time (in [[seconds]]). Examples: * [[Calcium sulfide]] with [[strontium sulfide]] with [[bismuth]] as activator, {{chem2|(Ca,Sr)S:Bi}}, yields blue light with glow times up to 12 hours, red and orange are modifications of the zinc sulfide formula. Red color can be obtained from strontium sulfide. * [[Zinc sulfide]] with about 5 ppm of a [[copper]] activator is the most common phosphor for the glow-in-the-dark toys and items. It is also called '''GS''' phosphor. *Mix of zinc sulfide and [[cadmium sulfide]] emit color depending on their ratio; increasing of the CdS content shifts the output color towards longer wavelengths; its persistence ranges between 1β10 hours. * [[Strontium aluminate]] activated by [[europium]] or [[dysprosium]], SrAl<sub>2</sub>O<sub>4</sub>:Eu(II):Dy(III), is a material developed in 1993 by Nemoto & Co. engineer Yasumitsu Aoki with higher brightness and significantly longer glow persistence; it produces green and aqua hues, where green gives the highest brightness and aqua the longest glow time.<ref name=jotes>{{Cite journal|last1=Matsuzawa|first1=T.|last2=Aoki|first2=Y.|last3=Takeuchi|first3=N.|last4=Murayama|first4=Y.|date=1996-08-01|title=A New Long Phosphorescent Phosphor with High Brightness, SrAl<sub>2</sub>O<sub>4</sub>: Eu<sup>2+</sup>, Dy<sup>3+</sup>|url=https://iopscience.iop.org/article/10.1149/1.1837067|journal=Journal of the Electrochemical Society|language=en|volume=143|issue=8|pages=2670β2673|doi=10.1149/1.1837067|bibcode=1996JElS..143.2670M |issn=0013-4651|url-access=subscription}}</ref><ref>{{Cite patent|number=US5424006A|title=Phosphorescent phosphor|gdate=1994-02-25|url=https://patents.google.com/patent/US5424006A/en}}</ref> SrAl<sub>2</sub>O<sub>4</sub>:Eu:Dy is about 10 times brighter, 10 times longer glowing, and 10 times more expensive than ZnS:Cu.<ref name=jotes /> The excitation [[wavelengths]] for strontium aluminate range from 200 to 450 nm. The wavelength for its green formulation is 520 nm, its blue-green version emits at 505 nm, and the blue one emits at 490 nm. Colors with longer [[wavelengths]] can be obtained from the strontium aluminate as well, though for the price of some loss of brightness. ==Phosphor degradation== Many phosphors tend to lose efficiency gradually by several mechanisms. The activators can undergo change of [[valence (chemistry)|valence]] (usually [[oxidation]]), the [[crystal lattice]] degrades, atoms β often the activators β diffuse through the material, the surface undergoes chemical reactions with the environment with consequent loss of efficiency or buildup of a layer absorbing the exciting and/or radiated energy, etc. The degradation of electroluminescent devices depends on frequency of driving current, the luminance level, and temperature; moisture impairs phosphor lifetime very noticeably as well. Harder, high-melting, water-insoluble materials display lower tendency to lose luminescence under operation.<ref name="advelectr"/> Examples: * BaMgAl<sub>10</sub>O<sub>17</sub>:Eu<sup>2+</sup> (BAM), a [[plasma display|plasma-display]] phosphor, undergoes oxidation of the dopant during baking. Three mechanisms are involved; absorption of oxygen atoms into oxygen vacancies on the crystal surface, [[diffusion]] of Eu(II) along the conductive layer, and [[electron transfer]] from Eu(II) to absorbed oxygen atoms, leading to formation of Eu(III) with corresponding loss of emissivity.<ref>{{cite journal|doi=10.1016/j.jlumin.2004.09.119|title=On phosphor degradation mechanism: thermal treatment effects|year=2005|last1=Bizarri|first1=G|first2=B|journal=[[Journal of Luminescence]]|volume=113|page=199|last2=Moine|bibcode = 2005JLum..113..199B|issue=3β4 }}</ref> Thin coating of [[aluminium phosphate]] or [[lanthanum(III) phosphate]] is effective in creating a [[barrier layer]] blocking access of oxygen to the BAM phosphor, for the cost of reduction of phosphor efficiency.<ref>Lakshmanan, p. 171.</ref> Addition of [[hydrogen]], acting as a [[reducing agent]], to [[argon]] in the plasma displays significantly extends the lifetime of BAM:Eu<sup>2+</sup> phosphor, by reducing the Eu(III) atoms back to Eu(II).<ref>{{cite journal|doi=10.1143/JJAP.48.092303|title=Lifetime Improvement of BaMgAl<sub>10</sub>O<sub>17</sub>:Eu<sup>2+</sup> Phosphor by Hydrogen Plasma Treatment|year=2009|last1=Tanno|first1=Hiroaki|first2=Takayuki|first3=Shuxiu|first4=Tsutae|first5=Hiroshi|journal=Japanese Journal of Applied Physics|volume=48|page=092303|last2=Fukasawa|last3=Zhang|last4=Shinoda|last5=Kajiyama|bibcode = 2009JaJAP..48i2303T|issue=9 |s2cid=94464554 }}</ref> * Y<sub>2</sub>O<sub>3</sub>:Eu phosphors under electron bombardment in presence of oxygen form a non-phosphorescent layer on the surface, where [[electronβhole pair]]s [[Carrier generation and recombination|recombine]] nonradiatively via surface states.<ref>{{cite journal|doi=10.1002/pssc.200404813|title=Degradation of Y<sub>2</sub>O<sub>3</sub>:Eu phosphor powders|year=2004|last1=Ntwaeaborwa|first1=O. M.|first2=K. T.|first3=H. C.|journal=Physica Status Solidi C|volume=1|page=2366|last2=Hillie|last3=Swart|bibcode = 2004PSSCR...1.2366N|issue=9 }}</ref> * ZnS:Mn, used in AC thin-film electroluminescent (ACTFEL) devices degrades mainly due to formation of [[deep-level trap]]s, by reaction of water molecules with the dopant; the traps act as centers for nonradiative recombination. The traps also damage the [[crystal lattice]]. Phosphor aging leads to decreased brightness and elevated threshold voltage.<ref>{{cite journal|doi=10.1143/JJAP.36.2728|title=Deep Traps and Mechanism of Brightness Degradation in Mn-doped ZnS Thin-Film Electroluminescent Devices Grown by Metal-Organic Chemical Vapor Deposition|year=1997|last1=Wang|first1=Ching-Wu|first2=Tong-Ji|first3=Yan-Kuin|first4=Meiso|journal=Japanese Journal of Applied Physics|volume=36|issue=5A|page=2728|last2=Sheu|last3=Su|last4=Yokoyama|bibcode = 1997JaJAP..36.2728W |s2cid=98131548 }}</ref> * ZnS-based phosphors in [[cathode-ray tube|CRT]]s and [[field emission display|FED]]s degrade by surface excitation, coulombic damage, build-up of electric charge, and thermal quenching. Electron-stimulated reactions of the surface are directly correlated to loss of brightness. The electrons dissociate impurities in the environment, the [[reactive oxygen species]] then attack the surface and form [[carbon monoxide]] and [[carbon dioxide]] with traces of [[carbon]], and nonradiative [[zinc oxide]] and [[zinc sulfate]] on the surface; the reactive [[hydrogen]] removes [[sulfur]] from the surface as [[hydrogen sulfide]], forming nonradiative layer of metallic [[zinc]]. Sulfur can be also removed as [[sulfur oxide]]s.<ref>Lakshmanan, pp. 51, 76</ref> * ZnS and CdS phosphors degrade by reduction of the metal ions by captured electrons. The M<sup>2+</sup> ions are reduced to M<sup>+</sup>; two M<sup>+</sup> then exchange an electron and become one M<sup>2+</sup> and one neutral M atom. The reduced metal can be observed as a visible darkening of the phosphor layer. The darkening (and the brightness loss) is proportional to the phosphor's exposure to electrons and can be observed on some CRT screens that displayed the same image (e.g. a terminal login screen) for prolonged periods.<ref>{{cite web|url=http://tubedevices.com/alek/pwl/luminofory/luminofory.ppt |title=PPT presentation in Polish (Link to achieved version; Original site isn't available) |publisher=Tubedevices.com |access-date=2016-12-15 |url-status=bot: unknown |archive-url=https://web.archive.org/web/20131228072818/http://tubedevices.com/alek/pwl/luminofory/luminofory.ppt |archive-date=2013-12-28 }}</ref> * Europium(II)-doped alkaline earth aluminates degrade by formation of [[F-center|color centers]].<ref name="advelectr"/> * {{chem|Y|2|SiO|5}}:Ce<sup>3+</sup> degrades by loss of luminescent Ce<sup>3+</sup> ions.<ref name="advelectr"/> * {{chem|Zn|2|SiO|4}}:Mn (P1) degrades by desorption of oxygen under electron bombardment.<ref name="advelectr"/> * Oxide phosphors can degrade rapidly in presence of [[fluoride]] ions, remaining from incomplete removal of flux from phosphor synthesis.<ref name="advelectr"/> * Loosely packed phosphors, e.g. when an excess of silica gel (formed from the potassium silicate binder) is present, have tendency to locally overheat due to poor thermal conductivity. E.g. {{chem|InBO|3}}:Tb<sup>3+</sup> is subject to accelerated degradation at higher temperatures.<ref name="advelectr"/> ==Applications== ===Lighting=== Phosphor layers provide most of the light produced by [[fluorescent lamp]]s, and are also used to improve the balance of light produced by [[metal halide lamp]]s. Various [[neon sign]]s use phosphor layers to produce different colors of light. [[Electroluminescent display]]s found, for example, in aircraft instrument panels, use a phosphor layer to produce glare-free illumination or as numeric and graphic display devices. Most white [[LED]] lamps consist of a blue or ultra-violet emitter with a phosphor coating that emits at longer wavelengths, giving a full spectrum of visible light. Unfocused and undeflected [[cathode-ray tube]]s have been used as [[Strobe light|stroboscope lamps]] since 1958.<ref>{{cite web |url=http://www.mif.pg.gda.pl/homepages/frank/sheets/074/c/CL60.pdf |publisher=[[Ferranti]], Ltd. |title=''Vacuum light sources β High speed stroboscopic light sources'' data sheet |date=August 1958 |access-date=7 May 2017 |url-status=live |archive-url=https://web.archive.org/web/20160920125303/http://www.mif.pg.gda.pl/homepages/frank/sheets/074/c/CL60.pdf |archive-date=20 September 2016 }}</ref> ===Phosphor thermometry=== {{main|Phosphor thermometry}} [[Phosphor thermometry]] is a temperature measurement approach that uses the temperature dependence of certain phosphors. For this, a phosphor coating is applied to a surface of interest and, usually, the decay time is the emission parameter that indicates temperature. Because the illumination and detection optics can be situated remotely, the method may be used for moving surfaces such as high speed motor surfaces. Also, phosphor may be applied to the end of an optical fiber as an optical analog of a thermocouple.{{Citation needed|date=December 2023}} ===Glow-in-the-dark toys=== {{main|Phosphorescence}} In these applications, the phosphor is directly added to the [[plastic]] used to mold the toys, or mixed with a binder for use as paints. ZnS:Cu phosphor is used in glow-in-the-dark cosmetic creams frequently used for [[Halloween]] [[make-up]]s. Generally, the persistence of the phosphor increases as the wavelength increases. See also [[lightstick]] for [[chemiluminescence]]-based glowing items. ===Oxygen sensing=== Quenching of the triplet state by O<sub>2</sub> (which has a triplet ground state) as a result of [[Dexter electron transfer|Dexter energy transfer]] is well known in solutions of phosphorescent heavy-metal complexes and doped polymers.<ref>{{Cite journal|last1=Lehner|first1=P.|last2=Staudinger|first2=C.|last3=Borisov|first3=S. M.|last4=Klimant|first4=l.|title=Ultra-sensitive optical oxygen sensors for characterization of nearly anoxic systems|journal= Nature Communications|date=2014|volume=5|page=4460|doi=10.1038/ncomms5460 |pmid=25042041 |pmc=4109599 |bibcode=2014NatCo...5.4460L }}</ref> In recent years, phosphorescence porous materials(such as [[Metalβorganic framework]]s and [[Covalent organic framework]]s) have shown promising oxygen sensing capabilities, for their non-linear gas-adsorption in ultra-low partial pressures of oxygen.<ref>{{Cite journal|last1=Hamzehpoor|first1=E|last2=Ruchlin|first2=C.|last3=Tao|first3=Y.|last4=Liu|first4=C. H.|last5=Titi|first5=H. M.|last6=Perepichka|first6=D. F.|title=Efficient room-temperature phosphorescence of covalent organic frameworks through covalent halogen doping|journal=Nature Chemistry|date=2022|volume=15|issue=1|pages=83β90|doi=10.1038/s41557-022-01070-4|pmid=36302870|s2cid=253183290}}</ref><ref>{{Cite journal|last1=Xie|first1=Z.|last2=Ma|first2=L.|last3=deKrafft|first3=K. E.|last4=Jin|first4=A.|last5=Lin|first5=W.|title=Porous phosphorescent coordination polymers for oxygen sensing|journal=J. Am. Chem. Soc.|date=2010|volume=132|issue=3 |pages=922β923|doi=10.1021/ja909629f |pmid=20041656 |bibcode=2010JAChS.132..922X }}</ref> ===Postage stamps=== [[Phosphor banded stamp]]s first appeared in 1959 as guides for machines to sort mail.<ref>[http://www.stamp-shop.com/dummies/see-phosphor.html SEEING PHOSPHOR BANDS on U.K. STAMPS] {{webarchive|url=https://web.archive.org/web/20151019005044/http://www.stamp-shop.com/dummies/see-phosphor.html |date=2015-10-19 }}.</ref> Around the world many varieties exist with different amounts of banding.<ref>[http://www.gbmachins.co.uk/html/phosphor_bands.html Phosphor Bands] {{webarchive|url=https://web.archive.org/web/20170317231538/http://gbmachins.co.uk/html/phosphor_bands.html |date=2017-03-17 }}.</ref> [[Postage stamp]]s are sometimes collected by whether or not they are [[Tagging (stamp)|"tagged"]] with phosphor (or printed on [[luminescent]] paper). ===Radioluminescence=== {{main|Radioluminescence}} Zinc sulfide phosphors are used with [[radioactive]] materials, where the phosphor was excited by the alpha- and beta-decaying isotopes, to create luminescent paint for dials of [[watch]]es and instruments ([[radium dials]]). Between 1913 and 1950 radium-228 and radium-226 were used to activate a phosphor made of [[silver]] [[dopant|doped]] zinc sulfide (ZnS:Ag), which gave a greenish glow. The phosphor is not suitable to be used in layers thicker than 25 mg/cm<sup>2</sup>, as the self-absorption of the light then becomes a problem. Furthermore, zinc sulfide undergoes degradation of its crystal lattice structure, leading to gradual loss of brightness significantly faster than the depletion of radium. ZnS:Ag coated [[spinthariscope]] screens were used by [[Ernest Rutherford]] in his experiments discovering [[atomic nucleus]]. [[Copper]] doped zinc sulfide (ZnS:Cu) is the most common phosphor used and yields blue-green light. Copper and [[magnesium]] doped zinc sulfide {{chem2|(ZnS:Cu,Mg)}} yields yellow-orange light. [[Tritium]] is also used as a source of radiation in various products utilizing [[tritium illumination]]. ===Electroluminescence=== {{main|Electroluminescence}} [[Electroluminescence]] can be exploited in light sources. Such sources typically emit from a large area, which makes them suitable for backlights of LCD displays. The excitation of the phosphor is usually achieved by application of high-intensity [[electric field]], usually with suitable frequency. Current electroluminescent light sources tend to degrade with use, resulting in their relatively short operation lifetimes. ZnS:Cu was the first formulation successfully displaying electroluminescence, tested at 1936 by [[Georges Destriau]] in Madame Marie Curie laboratories in Paris. Powder or AC electroluminescence is found in a variety of backlight and night light applications. Several groups offer branded EL offerings (e.g. '''IndiGlo''' used in some Timex watches) or "Lighttape", another trade name of an electroluminescent material, used in electroluminescent [[light strips]]. The Apollo space program is often credited with being the first significant use of EL for backlights and lighting.<ref>{{cite web |url=https://www.hq.nasa.gov/alsj/tnD7290Lighting.pdf |title=Apollo Lunar Surface Journal |access-date=2017-02-12 |url-status=live |archive-url=https://web.archive.org/web/20161221230335/http://www.hq.nasa.gov/alsj/tnD7290Lighting.pdf |archive-date=2016-12-21 }}</ref> ===White LEDs=== White [[light-emitting diode]]s are usually blue [[InGaN]] LEDs with a coating of a suitable material. [[Cerium]](III)-doped [[Yttrium aluminium garnet|YAG]] ('''YAG:Ce<sup>3+</sup>''', or '''Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>:Ce<sup>3+</sup>''') is often used; it absorbs the light from the blue LED and emits in a broad range from greenish to reddish, with most of its output in yellow. This yellow emission combined with the remaining blue emission gives the "white" light, which can be adjusted to color temperature as warm (yellowish) or cold (bluish) white. The pale yellow emission of the Ce<sup>3+</sup>:YAG can be tuned by substituting the cerium with other rare-earth elements such as [[terbium]] and [[gadolinium]] and can even be further adjusted by substituting some or all of the aluminium in the YAG with gallium. However, this process is not one of phosphorescence. The yellow light is produced by a process known as [[scintillation (physics)|scintillation]], the complete absence of an afterglow being one of the characteristics of the process. Some [[rare-earth]]-[[dopant|doped]] [[Sialon]]s are [[photoluminescent]] and can serve as phosphors. [[Europium]](II)-doped Ξ²-SiAlON absorbs in [[ultraviolet]] and [[visible light]] spectrum and emits intense broadband visible emission. Its luminance and color does not change significantly with temperature, due to the temperature-stable crystal structure. It has a great potential as a green down-conversion phosphor for white [[LED]]s; a yellow variant also exists (Ξ±-SiAlON<ref>{{Cite web|url=https://tech.nikkeibp.co.jp/dm/english/NEWS_EN/20090915/175305/|title=Sharp to Employ White LED Using Sialon|last=XTECH|first=NIKKEI|website=NIKKEI XTECH|language=en|access-date=2019-01-10}}</ref>). For white LEDs, a blue LED is used with a yellow phosphor, or with a green and yellow SiAlON phosphor and a red CaAlSiN<sub>3</sub>-based (CASN) phosphor.<ref>{{cite journal|url=http://www.science24.com/paper/15977|title=Luminescence and temperature dependency of Ξ²-SiAlON phosphor|author=Youn-Gon Park|journal=Samsung Electro Mechanics Co|display-authors=etal|url-status=dead|archive-url=https://web.archive.org/web/20100412152349/http://www.science24.com/paper/15977|archive-date=2010-04-12|access-date=2009-09-24}}</ref><ref>{{cite news|url=http://techon.nikkeibp.co.jp/english/NEWS_EN/20090915/175305/|title=Sharp to Employ White LED Using Sialon|date=Sep 15, 2009|author=Hideyoshi Kume, Nikkei Electronics|url-status=live|archive-url=https://web.archive.org/web/20120223124648/http://techon.nikkeibp.co.jp/english/NEWS_EN/20090915/175305/|archive-date=2012-02-23}}</ref><ref>{{cite journal|url=http://sciencelinks.jp/j-east/article/200602/000020060205A1031052.php|title=New sialon phosphors and white LEDs|author=Naoto, Hirosaki|journal=Oyo Butsuri|volume=74|issue=11|page=1449|year=2005|display-authors=etal|url-status=dead|archive-url=https://web.archive.org/web/20100404151444/http://sciencelinks.jp/j-east/article/200602/000020060205A1031052.php|archive-date=2010-04-04}}</ref> White LEDs can also be made by coating near-ultraviolet-emitting LEDs with a mixture of high-efficiency europium-based red- and blue-emitting phosphors plus green-emitting copper- and aluminium-doped zinc sulfide {{chem2|(ZnS:Cu,Al)}}. This is a method analogous to the way [[fluorescent lamp]]s work. Some newer white LEDs use a yellow and blue emitter in series, to approximate white; this technology is used in some Motorola phones such as the Blackberry as well as LED lighting and the original-version stacked emitters by using GaN on SiC on InGaP but was later found to fracture at higher drive currents. Many white LEDs used in general lighting systems can be used for data transfer, as, for example, in systems that modulate the LED to act as a [[beacon]].<ref>{{cite journal|url=http://ntv.ifmo.ru/en/article/11192/chastotnye_harakteristiki_sovremennyh_svetodiodnyh_lyuminofornyh_materialov.htm|title=Frequency characteristics of modern LED phosphor materials|author=Fudin, M.S.|journal=Scientific and Technical Journal of Information Technologies, Mechanics and Optics|volume=14|issue=6|page=71|year=2014|display-authors=etal|url-status=live|archive-url=https://web.archive.org/web/20150626162616/http://ntv.ifmo.ru/en/article/11192/chastotnye_harakteristiki_sovremennyh_svetodiodnyh_lyuminofornyh_materialov.htm|archive-date=2015-06-26}}</ref> It is also common for white LEDs to use phosphors other than Ce:YAG, or to use two or three phosphors to achieve a higher CRI, often at the cost of efficiency. Examples of additional phosphors are R9, which produces a saturated red, nitrides which produce red, and aluminates such as lutetium aluminum garnet that produce green. Silicate phosphors are brighter but fade more quickly, and are used in LCD LED backlights in mobile devices. LED phosphors can be placed directly over the die or made into a dome and placed above the LED: this approach is known as a remote phosphor.<ref>{{Cite web|url=https://www.electronicsweekly.com/news/products/led/discussing-led-lighting-phosphors-2014-03/|title=Discussing LED lighting phosphors|first=Steve|last=Bush|date=March 14, 2014}}</ref> Some colored LEDs, instead of using a colored LED, use a blue LED with a colored phosphor because such an arrangement is more efficient than a colored LED. Oxynitride phosphors can also be used in LEDs. The precursors used to make the phosphors may degrade when exposed to air.<ref>{{cite journal |last1=Setlur |first1=Anant A. |title=Phosphors for LED-based Solid-State Lighting |journal=The Electrochemical Society Interface |date=1 December 2009 |volume=18 |issue=4 |pages=32β36 |doi=10.1149/2.F04094IF |url=https://www.electrochem.org/dl/interface/wtr/wtr09/wtr09_p032-036.pdf |access-date=5 December 2022 |language=en}}</ref> ===Cathode-ray tubes===<!-- This section is linked from Cathode-ray tube --> [[File:CRT phosphors.png|thumb|right|400px|Spectra of constituent blue, green and red phosphors in a common cathode-ray tube]] [[Cathode-ray tube]]s produce signal-generated light patterns in a (typically) round or rectangular format. Bulky CRTs were used in the black-and-white television (TV) sets that became popular in the 1950s, developed into color CRTs in the late 1960s, and used in virtually all color TVs and computer monitors until the mid-2000s. In the late 20th century, advanced electronics made new wide-deflection, "short tube" CRT technology viable, making CRTs more compact, but still bulky and heavy. As the original video display technology, having no viable competition for more than 40 years and dominance for over 50 years, the CRT ceased to be the main type of video display in use only around 2010. In addition to direct-view CRTs, CRT projection tubes were the basis of all projection TVs and computer video projectors of both front and rear projection types until at least the late 1990s. CRTs have also been widely used in scientific and engineering instrumentation, such as [[oscilloscope]]s, usually with a single phosphor color, typically green. Phosphors for such applications may have long afterglow, for increased image persistence. A variation of the display CRT, used prior to the 1980s, was the CRT [[storage tube]], a digital memory device which (in later forms) also provided a visible display of the stored data, using a variation of the same electron-beam excited phosphor technology. The process of producing light in CRTs by electron-beam excited phosphorescence yields much faster signal response times than even modern (2020s) [[LCD]]s can achieve, which makes [[light pen]]s and light gun games possible with CRTs, but not LCDs. Also in contrast to most other video display types, because CRT technology draws an image by scanning an electron beam (or a formation of three beams) across a phosphor surface, a CRT has no intrinsic "native resolution" and does not require scaling to display raster images at different resolutions; the CRT can display any raster format natively, within the limits defined by the electron beam spot size and, for a color CRT, the dot pitch of the phosphor. Because of this operating principle, CRTs can produce images using either raster and vector imaging methods. Vector displays are impossible for display technologies that have permanent discrete pixels, including all LCDs, [[Plasma display|plasma display panels]], [[Digital micromirror device|DMD]] projectors, and [[OLED]] (LED matrix, e.g. TFT OLED) panels. The phosphors can be deposited as either [[thin film]], or as discrete particles, a powder bound to the surface. Thin films have better lifetime and better resolution, but provide less bright and less efficient image than powder ones. This is caused by multiple internal reflections in the thin film, scattering the emitted light. '''White''' (in black-and-white): The mix of zinc cadmium sulfide and zinc sulfide silver, the {{chem2|ZnS:Ag + (Zn,Cd)S:Ag}} is the white '''P4''' phosphor used in black and white television CRTs. Mixes of yellow and blue phosphors are usual. Mixes of red, green and blue, or a single white phosphor, can also be encountered. '''Red:''' [[Yttrium]] [[oxide]]-[[sulfide]] activated with europium is used as the red phosphor in color CRTs. The development of color TV took a long time due to the search for a red phosphor. The first red emitting rare-earth phosphor, YVO<sub>4</sub>:Eu<sup>3+</sup>, was introduced by Levine and Palilla as a primary color in television in 1964.<ref>{{cite journal| doi = 10.1063/1.1723611| title = A new, highly efficient red-emitting cathodoluminescent phosphor (YVO<sub>4</sub>:Eu) for color television| year = 1964|author = Levine, Albert K.| journal = Applied Physics Letters| volume = 5|page = 118| first2 = Frank C.| last2 = Palilla|bibcode = 1964ApPhL...5..118L| issue = 6 }}</ref> In single crystal form, it was used as an excellent polarizer and laser material.<ref>{{cite journal| doi = 10.1063/1.98500| title = Highly efficient Nd:YVO<sub>4</sub> diode-laser end-pumped laser| year = 1987|author = Fields, R. A.| journal = Applied Physics Letters| volume = 51|page = 1885| first2 = M.| first3 = C. L.| last2 = Birnbaum| last3 = Fincher|bibcode = 1987ApPhL..51.1885F| issue = 23 | doi-access = free}}</ref> '''Yellow:''' When mixed with [[cadmium sulfide]], the resulting '''zinc cadmium sulfide''' {{chem2|(Zn,Cd)S:Ag}}, provides strong yellow light. '''Green:''' Combination of zinc sulfide with [[copper]], the '''P31''' phosphor or {{chem2|ZnS:Cu}}, provides green light peaking at 531 nm, with long glow. '''Blue:''' Combination of zinc sulfide with few ppm of [[silver]], the ZnS:Ag, when excited by electrons, provides strong blue glow with maximum at 450 nm, with short afterglow with 200 nanosecond duration. It is known as the '''P22B''' phosphor. This material, '''zinc sulfide silver''', is still one of the most efficient phosphors in cathode-ray tubes. It is used as a blue phosphor in color CRTs. The phosphors are usually poor electrical conductors. This may lead to deposition of residual charge on the screen, effectively decreasing the energy of the impacting electrons due to electrostatic repulsion (an effect known as "sticking"). To eliminate this, a thin layer of aluminium (about 100 nm) is deposited over the phosphors, usually by vacuum evaporation, and connected to the conductive layer inside the tube. This layer also reflects the phosphor light to the desired direction, and protects the phosphor from ion bombardment resulting from an imperfect vacuum. To reduce the image degradation by reflection of ambient light, [[Contrast (vision)|contrast]] can be increased by several methods. In addition to black masking of unused areas of screen, the phosphor particles in color screens are coated with pigments of matching color. For example, the red phosphors are coated with [[ferric oxide]] (replacing earlier Cd(S,Se) due to cadmium toxicity), blue phosphors can be coated with marine blue ([[cobalt(II) oxide|CoO]]Β·''n''[[alumina|{{chem|Al|2|O|3}}]]) or [[ultramarine]] ({{chem|Na|8|Al|6|Si|6|O|24|S|2}}). Green phosphors based on ZnS:Cu do not have to be coated due to their own yellowish color.<ref name="advelectr">{{cite book|author=Peter W. Hawkes |title=Advances in electronics and electron physics |url=https://books.google.com/books?id=FE_Hvcbkpa4C&pg=PA350 |access-date=9 January 2012 |date=1 October 1990 |publisher=Academic Press |isbn=978-0-12-014679-6 |pages=350β}}</ref> ====Black-and-white television CRTs==== The black-and-white television screens require an emission color close to white. Usually, a combination of phosphors is employed. The most common combination is {{chem2|ZnS:Ag + (Zn,Cd)S:Cu,Al}} (blue + yellow). Other ones are {{chem2|ZnS:Ag + (Zn,Cd)S:Ag}} (blue + yellow), and {{chem2|ZnS:Ag + ZnS:Cu,Al + Y2O2S:Eu(3+)}} (blue + green + red β does not contain cadmium and has poor efficiency). The color tone can be adjusted by the ratios of the components. As the compositions contain discrete grains of different phosphors, they produce image that may not be entirely smooth. A single, white-emitting phosphor, {{chem2|(Zn,Cd)S:Ag,Au,Al}} overcomes this obstacle. Due to its low efficiency, it is used only on very small screens. The screens are typically covered with phosphor using sedimentation coating, where particles [[suspension (chemistry)|suspended]] in a solution are let to settle on the surface.<ref name="lumdisp">Lakshmanan, p. 54.</ref> ====Reduced-palette color CRTs==== For displaying of a limited palette of colors, there are a few options. In [[penetron|'''beam penetration tubes''']], different color phosphors are layered and separated with dielectric material. The acceleration voltage is used to determine the energy of the electrons; lower-energy ones are absorbed in the top layer of the phosphor, while some of the higher-energy ones shoot through and are absorbed in the lower layer. So either the first color or a mixture of the first and second color is shown. With a display with red outer layer and green inner layer, the manipulation of accelerating voltage can produce a continuum of colors from red through orange and yellow to green. Another method is using a mixture of two phosphors with different characteristics. The brightness of one is linearly dependent on electron flux, while the other one's brightness saturates at higher fluxesβthe phosphor does not emit any more light regardless of how many more electrons impact it. At low electron flux, both phosphors emit together; at higher fluxes, the luminous contribution of the nonsaturating phosphor prevails, changing the combined color.<ref name="lumdisp"/> Such displays can have high resolution, due to absence of two-dimensional structuring of RGB CRT phosphors. Their color palette is, however, very limited. They were used e.g. in some older military radar displays. ====Color television CRTs==== {{missing information|section|time period of each phosphor composition|date=October 2020}} The phosphors in color CRTs need higher contrast and resolution than the black-and-white ones. The energy density of the electron beam is about 100 times greater than in black-and-white CRTs; the electron spot is focused to about 0.2 mm diameter instead of about 0.6 mm diameter of the black-and-white CRTs. Effects related to electron irradiation degradation are therefore more pronounced. Color CRTs require three different phosphors, emitting in red, green and blue, patterned on the screen. Three separate electron guns are used for color production (except for displays that use [[beam-index tube]] technology, which is rare). The red phosphor has always been a problem, being the dimmest of the three necessitating the brighter green and blue electron beam currents be adjusted down to make them equal the red phosphor's lower brightness. This made early color TVs only usable indoors as bright light made it impossible to see the dim picture, while portable black-and-white TVs viewable in outdoor sunlight were already common. The composition of the phosphors changed over time, as better phosphors were developed and as environmental concerns led to lowering the content of cadmium and later abandoning it entirely. The {{chem2|(Zn,Cd)S:Ag,Cl}} was replaced with {{chem2|(Zn,Cd)S:Cu,Al}} with lower cadmium/zinc ratio, and then with cadmium-free {{chem2|ZnS:Cu,Al}}. The blue phosphor stayed generally unchanged, a silver-doped zinc sulfide. The green phosphor initially used manganese-doped zinc silicate, then evolved through silver-activated cadmium-zinc sulfide, to lower-cadmium copper-aluminium activated formula, and then to cadmium-free version of the same. The red phosphor saw the most changes; it was originally manganese-activated zinc phosphate, then a silver-activated cadmium-zinc sulfide, then the europium(III) activated phosphors appeared; first in an [[yttrium vanadate]] matrix, then in [[yttrium oxide]] and currently in [[yttrium oxysulfide]]. The evolution of the phosphors was therefore (ordered by B-G-R): * {{chem2|ZnS:Ag}} – {{chem2|Zn2SiO4:Mn}} – {{chem2|Zn3(PO4)2:Mn}} * {{chem2|ZnS:Ag}} – {{chem2|(Zn,Cd)S:Ag}} – {{chem2|(Zn,Cd)S:Ag}} * {{chem2|ZnS:Ag}} – {{chem2|(Zn,Cd)S:Ag}} – {{chem2|YVO4:Eu(3+)}} (1964–?) * {{chem2|ZnS:Ag}} – {{chem2|(Zn,Cd)S:Cu,Al}} – {{chem2|Y2O2S:Eu(3+)}} or {{chem2|Y2O3:Eu(3+)}} * {{chem2|ZnS:Ag}} – {{chem2|ZnS:Cu,Al}} or {{chem2|ZnS:Au,Cu,Al}} – {{chem2|Y2O2S:Eu(3+)}}<ref name="lumdisp"/> ====Projection televisions==== For [[projection television]]s, where the beam power density can be two orders of magnitude higher than in conventional CRTs, some different phosphors have to be used. For blue color, {{chem2|ZnS:Ag,Cl}} is employed. However, it saturates. {{chem2|(La,Gd)OBr:Ce,Tb(3+)}} can be used as an alternative that is more linear at high energy densities. For green, a [[terbium]]-activated {{chem2|Gd2O2Tb(3+)}}; its color purity and brightness at low excitation densities is worse than the zinc sulfide alternative, but it behaves linear at high excitation energy densities, while zinc sulfide saturates. However, it also saturates, so {{chem2|Y3Al5O12:Tb(3+)}} or {{chem2|Y2SiO5:Tb(3+)}} can be substituted. {{chem2|LaOBr:Tb(3+)}} is bright but water-sensitive, degradation-prone, and the plate-like morphology of its crystals hampers its use; these problems are solved now, so it is gaining use due to its higher linearity. {{chem2|Y2O2S:Eu(3+)}} is used for red emission.<ref name="lumdisp"/> ==Standard phosphor types== {| class="wikitable sortable" |+Standard phosphor types<ref>{{cite book|chapter-url = https://books.google.com/books?id=lWlcJEDukRIC&pg=PA469|title =Phosphor handbook|author = Shionoya, Shigeo |chapter = VI: Phosphors for cathode ray tubes|isbn = 978-0-8493-7560-6|year = 1999|publisher = CRC Press|location = Boca Raton, Fla.}}</ref><ref>{{cite web|url=http://www.bunkerofdoom.com/tubes/crt/crt_phosphor_research.pdf|title=Cathode Ray Tube Phosphors|last=Jankowiak|first=Patrick|publisher=bunkerofdoom.com|url-status=live|archive-url=https://web.archive.org/web/20130119132302/http://www.bunkerofdoom.com/tubes/crt/crt_phosphor_research.pdf|archive-date=19 January 2013|access-date=1 May 2012}}{{unreliable source?|date=January 2013}}<!-- Enthusiast's site - lacks backing of recognised authority ---></ref> |- ! Phosphor ! [[Chemical formula|Composition]] ! Color ! [[Wavelength]] ! Peak width ! Persistence ! Usage ! Notes |- |P1, GJ | [[Willemite|Zn<sub>2</sub>SiO<sub>4</sub>]]:Mn ([[Willemite]]) | Green | 525 nm | 40 nm<ref name=o /> | 1-100ms | CRT, Lamp | Oscilloscopes and [[monochrome monitor]]s |- |P2 | ZnS:Cu(Ag)(B*) | Blue-Green | 543 nm | β | Long | CRT | Oscilloscopes |- |P3 | Zn<sub>8</sub>:BeSi<sub>5</sub>O<sub>19</sub>:Mn | Yellow | 602 nm | β | Medium/13 ms | CRT | [[Amber (color)|Amber]] monochrome monitors |- |P4 | ZnS:Ag+(Zn,Cd)S:Ag | White | 565,540 nm | β | Short | CRT | Black and white TV CRTs and display tubes. |- |P4 (Cd-free) | ZnS:Ag+ZnS:Cu+[[Yttrium oxysulfide|Y<sub>2</sub>O<sub>2</sub>S]]:Eu | White | β | β | Short | CRT | Black and white TV CRTs and display tubes, Cd free. |- |P5 | [[Scheelite|CaWO<sub>4</sub>]]:W | Blue | 430 nm | β | Very Short | CRT | Film |- |P6 | ZnS:Ag+ZnS:CdS:Ag | White | 565,460 nm | β | Short | CRT | |- |P7 | (Zn,Cd)S:Cu | Blue with Yellow persistence | 558,440 nm | β | Long | CRT | [[Radar]] [[Plan position indicator|PPI]], old EKG monitors, early oscilloscopes |- |P10 | KCl | Green-absorbing [[scotophor]] | β | β | Long | [[Skiatron|Dark-trace CRT]]s | Radar screens; turns from translucent white to dark magenta, stays changed until erased by heating or infrared light |- |P11, BE | ZnS:Ag,Cl or ZnS:Zn | Blue | 460 nm | β | 0.01-1 ms | CRT, VFD | Display tubes and [[vacuum fluorescent display|VFD]]s; Oscilloscopes (for fast photographic recording)<ref>{{cite book |last=Keller |first=Peter |date=1991 |title=The Cathode-Ray Tube: Technology, History, and Applications |location= |publisher=Palisades Press |page=17 |isbn=0963155903}} </ref> |- |P12 | Zn(Mg)F<sub>2</sub>:Mn | Orange | 590 nm | β | Medium/long | CRT | [[Radar]] |- |P13 | MgSi<sub>2</sub>O<sub>6</sub>:Mn | Reddish-Orange | 640 nm | β | Medium | CRT | Flying spot scanning systems and photographic applications |- |P14 | ZnS:Ag on ZnS:CdS:Cu | Blue with Orange persistence | β | β | Medium/long | CRT | [[Radar]] [[Plan position indicator|PPI]], old EKG monitors |- |P15 | ZnO:Zn | Blue-Green | 504,391 nm | β | Extremely Short | CRT | Television pickup by [[Flying-spot scanner|flying-spot scanning]] |- |P16 | CaMgSi<sub>2</sub>O<sub>6</sub>:Ce | Blue-Purple | 380 nm | β | Very Short | CRT | Flying spot scanning systems and photographic applications |- |P17 | ZnO,ZnCdS:Cu | Blue-Yellow | 504,391 nm | β | Blue-Short, Yellow-Long | CRT | |- |P18 | CaMgSi<sub>2</sub>O<sub>6</sub>:Ti, BeSi<sub>2</sub>O<sub>6</sub>:Mn | White | 545,405 nm | β | Medium to Short | CRT | |- |P19, LF | (KF,MgF<sub>2</sub>):Mn | Orange-Yellow | 590 nm | β | Long | CRT | Radar screens |- |P20, KA | (Zn,Cd)S:Ag or (Zn,Cd)S:Cu | Yellow-Green | 555 nm | β | 1β100 ms | CRT | Display tubes |- |P21 | MgF<sub>2</sub>:Mn<sup>2+</sup> | Reddish | 605 nm | β | β | CRT, Radar | Registered by Allen B DuMont Laboratories |- |P22R | Y<sub>2</sub>O<sub>2</sub>S:Eu+Fe<sub>2</sub>O<sub>3</sub> | Red | 611 nm | β | Short | CRT | Red phosphor for TV screens |- |P22G | (Zn,Cd)S:Cu,Al | Green | 530 nm | β | Short | CRT | Green phosphor for TV screens |- |P22B | ZnS:Ag+[[cobalt|Co]]-on-[[aluminium oxide|Al<sub>2</sub>O<sub>3</sub>]] | Blue | β | β | Short | CRT | Blue phosphor for [[television|TV]] screens |- |P23 | ZnS:Ag+(Zn,Cd)S:Ag | White | 575,460 nm | β | Short | CRT, Direct viewing television | Registered by United States Radium Corporation. |- |P24, GE | [[Zinc oxide|ZnO]]:Zn | Green | 505 nm | β | 1β10 ΞΌs | VFD |most common phosphor in [[vacuum fluorescent display]]s.<ref>{{Cite web | url=http://www.futaba.co.jp/en/display/vfd/index.html | title=VFDο½Futaba Corporation| date=27 February 2021}}</ref> |- |P25 | CaSi<sub>2</sub>O<sub>6</sub>:Pb:Mn | Orange | 610 nm | β | Medium | CRT | Military Displays - 7UP25 CRT |- |P26, LC | (KF,MgF<sub>2</sub>):Mn | Orange | 595 nm | β | Long | CRT | Radar screens |- |P27 | ZnPO<sub>4</sub>:Mn | Reddish Orange | 635 nm | β | Medium | CRT | Color TV monitor service |- |P28, KE | (Zn,Cd)S:Cu,Cl | Yellow | β | β | Medium | CRT | Display tubes |- |P29 | Alternating P2 and P25 stripes | Blue-Green/Orange stripes | β | β | Medium | CRT | Radar screens |- |P31, GH | ZnS:Cu or ZnS:Cu,Ag | Yellowish-green | β | β | 0.01-1 ms | CRT | Oscilloscopes and monochrome monitors |- |P33, LD | MgF<sub>2</sub>:Mn | Orange | 590 nm | β | > 1sec | CRT | Radar screens |- |P34 | β | Bluish Green-Yellow Green | β | β | Very Long | CRT | β |- |P35 | ZnS,ZnSe:Ag | Blue-White | 455 nm | β | Medium Short | CRT | Photographic registration on orthochromatic film materials |- |P38, LK | (Zn,Mg)F<sub>2</sub>:Mn | Orange-Yellow | 590 nm | β | Long | CRT | Radar screens |- |P39, GR | [[Willemite|Zn<sub>2</sub>SiO<sub>4</sub>]]:Mn,As | Green | 525 nm | β | Long | CRT | Display tubes |- |P40, GA | ZnS:Ag+(Zn,Cd)S:Cu | White | β | β | Long | CRT | Display tubes |- |P43, GY | [[Gadolinium oxysulfide|Gd<sub>2</sub>O<sub>2</sub>S]]:Tb | Yellow-Green | 545 nm | β | Medium | CRT | Display tubes, Electronic Portal Imaging Devices (EPIDs) used in radiation therapy linear accelerators for cancer treatment |- |P45, WB | Y<sub>2</sub>O<sub>2</sub>S:Tb | White | 545 nm | β | Short | CRT | Viewfinders |- |P46, KG |[[Yttrium aluminium garnet|Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>]]:Ce | Green | 530 nm | β | Very short (70ns) | CRT | [[Beam-index tube]] |- |P47, BH | [[Yttrium silicate|Y<sub>2</sub>SiO<sub>5</sub>]]:Ce | Blue | 400 nm | β | Very short | CRT | Beam-index tube |- |P53, KJ | [[Yttrium aluminium garnet|Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>]]:Tb | Yellow-Green | 544 nm | β | Short | CRT | Projection tubes |- |P55, BM | ZnS:Ag,Al | Blue | 450 nm | β | Short | CRT | Projection tubes |- | | ZnS:Ag | Blue | 450 nm | β | β | CRT | β |- | |ZnS:Cu,Al or ZnS:Cu,Au,Al | Green | 530 nm | β | β |CRT | β |- | | (Zn,Cd)S:Cu,Cl+(Zn,Cd)S:Ag,Cl |White | β | β | β |CRT | β |- | |[[Yttrium silicate|Y<sub>2</sub>SiO<sub>5</sub>]]:Tb | Green | 545 nm | β | β |CRT |Projection tubes |- | | Y<sub>2</sub>OS:Tb | Green | 545 nm | β | β |CRT | Display tubes |- | | Y<sub>3</sub>(Al,Ga)<sub>5</sub>O<sub>12</sub>:Ce | Green | 520 nm | β |Short |CRT |Beam-index tube |- | | Y<sub>3</sub>(Al,Ga)<sub>5</sub>O<sub>12</sub>:Tb | Yellow-Green | 544 nm | β |Short |CRT |Projection tubes |- | |[[Indium borate|InBO<sub>3</sub>]]:Tb | Yellow-Green | 550 nm | β | β |CRT | β |- | | InBO<sub>3</sub>:Eu | Yellow | 588 nm | β | β |CRT | β |- | | InBO<sub>3</sub>:Tb+InBO<sub>3</sub>:Eu |amber | β | β | β |CRT |Computer displays |- | | InBO<sub>3</sub>:Tb+InBO<sub>3</sub>:Eu+ZnS:Ag |White | β | β | β |CRT | β |- | | (Ba,Eu)Mg<sub>2</sub>Al<sub>16</sub>O<sub>27</sub> |Blue | β | β | β |Lamp | Trichromatic fluorescent lamps |- | | (Ce,Tb)MgAl<sub>11</sub>O<sub>19</sub> | Green | 546 nm | 9 nm | β |Lamp | Trichromatic fluorescent lamps<ref name=o /> |- |BAM |BaMgAl<sub>10</sub>O<sub>17</sub>:Eu,Mn |Blue |450 nm | β | β |Lamp, displays | Trichromatic fluorescent lamps |- | |BaMg<sub>2</sub>Al<sub>16</sub>O<sub>27</sub>:Eu(II) |Blue |450 nm | 52 nm | β |Lamp | Trichromatic fluorescent lamps<ref name=o /> |- |BAM |BaMgAl<sub>10</sub>O<sub>17</sub>:Eu,Mn |Blue-Green |456 nm,514 nm | β | β |Lamp | β |- | |BaMg<sub>2</sub>Al<sub>16</sub>O<sub>27</sub>:Eu(II),Mn(II) |Blue-Green |456 nm, 514 nm | 50 nm 50%<ref name=o>{{cite web|access-date=2009-06-06 |url=http://www.sylvania.com/BusinessProducts/MaterialsandComponents/LightingComponents/Phosphor/FluorescentLamps/ |title=Osram Sylvania fluorescent lamps |url-status=dead |archive-url=https://web.archive.org/web/20110724123140/http://www.sylvania.com/BusinessProducts/MaterialsandComponents/LightingComponents/Phosphor/FluorescentLamps/ |archive-date=July 24, 2011 }}</ref> | β |Lamp | |- | |Ce<sub>0.67</sub>Tb<sub>0.33</sub>MgAl<sub>11</sub>O<sub>19</sub>:Ce,Tb | Green | 543 nm | β | β |Lamp | Trichromatic fluorescent lamps |- | |Zn<sub>2</sub>SiO<sub>4</sub>:Mn,Sb<sub>2</sub>O<sub>3</sub> | Green | 528 nm | β | β |Lamp | β |- | |[[calcium silicate|CaSiO<sub>3</sub>]]:Pb,Mn | Orange-Pink |615 nm |83 nm<ref name=o /> | β |Lamp | |- | |[[calcium tungstate|CaWO<sub>4</sub>]] ([[Scheelite]]) |Blue |417 nm | β | β |Lamp | β |- | |CaWO<sub>4</sub>:Pb |Blue |433 nm/466 nm |111 nm | β |Lamp |Wide bandwidth<ref name=o /> |- | |[[magnesium tungstate|MgWO<sub>4</sub>]] |Pale Blue |473 nm |118 nm | β |Lamp |Wide bandwidth, deluxe blend component <ref name=o /> |- | | (Sr,Eu,Ba,Ca)<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>Cl |Blue | β | β | β |Lamp | Trichromatic fluorescent lamps |- | |Sr<sub>5</sub>Cl(PO<sub>4</sub>)<sub>3</sub>:Eu(II) |Blue |447 nm |32 nm<ref name=o /> | β |Lamp | β |- | | (Ca,Sr,Ba)<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>Cl<sub>2</sub>:Eu |Blue |452 nm | β | β |Lamp | β |- | | (Sr,Ca,Ba)<sub>10</sub>(PO<sub>4</sub>)<sub>6</sub>Cl<sub>2</sub>:Eu |Blue |453 nm | β | β |Lamp | Trichromatic fluorescent lamps |- | |[[strontium phosphate|Sr<sub>2</sub>P<sub>2</sub>O<sub>7</sub>:Sn(II)]] |Blue |460 nm | 98 nm | β |Lamp |Wide bandwidth, deluxe blend component<ref name=o /> |- | |Sr<sub>6</sub>P<sub>5</sub>BO<sub>20</sub>:Eu |Blue-Green |480 nm |82 nm<ref name=o /> | β |Lamp | β |- | |Ca<sub>5</sub>F(PO<sub>4</sub>)<sub>3</sub>:Sb |Blue |482 nm |117 nm | β |Lamp |Wide bandwidth<ref name=o /> |- | | (Ba,Ti)<sub>2</sub>P<sub>2</sub>O<sub>7</sub>:Ti |Blue-Green |494 nm |143 nm | β |Lamp |Wide bandwidth, deluxe blend component <ref name=o /> |- | |3[[strontium phosphate|Sr<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>]].[[strontium fluoride|SrF<sub>2</sub>]]:Sb,Mn |Blue | 502 nm | β | β |Lamp | β |- | |Sr<sub>5</sub>F(PO<sub>4</sub>)<sub>3</sub>:Sb,Mn |Blue-Green | 509 nm |127 nm | β |Lamp |Wide bandwidth<ref name=o /> |- | |Sr<sub>5</sub>F(PO<sub>4</sub>)<sub>3</sub>:Sb,Mn |Blue-Green | 509 nm |127 nm | β |Lamp |Wide bandwidth<ref name=o /> |- | |[[lanthanum phosphate|LaPO<sub>4</sub>]]:Ce,Tb | Green | 544 nm | β | β |Lamp | Trichromatic fluorescent lamps |- | | (La,Ce,Tb)PO<sub>4</sub> | Green | β | β | β |Lamp | Trichromatic fluorescent lamps |- | | (La,Ce,Tb)PO<sub>4</sub>:Ce,Tb | Green | 546 nm |6 nm | β |Lamp | Trichromatic fluorescent lamps<ref name=o /> |- | |[[calcium phosphate|Ca<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>]].[[calcium fluoride|CaF<sub>2</sub>]]:Ce,Mn | Yellow | 568 nm | β | β |Lamp | β |- | | (Ca,Zn,Mg)<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>:Sn | Orange-Pink |610 nm |146 nm | β |Lamp |Wide bandwidth, blend component<ref name=o /> |- | | (Zn,Sr)<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>:Mn | Orange-Red |625 nm | β | β |Lamp | β |- | | (Sr,Mg)<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>:Sn | Light Orange-Pink |626 nm |120 nm | β |Fluorescent lamps |Wide bandwidth, deluxe blend component<ref name=o /> |- | | (Sr,Mg)<sub>3</sub>(PO<sub>4</sub>)<sub>2</sub>:Sn(II) | Orange-red |630 nm | β | β |Fluorescent lamps | β |- | |Ca<sub>5</sub>F(PO<sub>4</sub>)<sub>3</sub>:Sb,Mn |3800K | β | β | β |Fluorescent lamps |Lite-white blend<ref name=o /> |- | |Ca<sub>5</sub>(F,Cl)(PO<sub>4</sub>)<sub>3</sub>:Sb,Mn |White-Cold/Warm | β | β | β |Fluorescent lamps | 2600 to 9900 K, for very high output lamps<ref name=o /> |- | | (Y,Eu)<sub>2</sub>O<sub>3</sub> | Red | β | β | β |Lamp | Trichromatic fluorescent lamps |- | |[[yttrium oxide|Y<sub>2</sub>O<sub>3</sub>:Eu(III)]] | Red |611 nm |4 nm | β |Lamp | Trichromatic fluorescent lamps<ref name=o /> |- | | Mg<sub>4</sub>(F)GeO<sub>6</sub>:Mn | Red |658 nm |17 nm | β |High-pressure mercury lamps | <ref name=o /> |- | | Mg<sub>4</sub>(F)(Ge,Sn)O<sub>6</sub>:Mn | Red |658 nm | β | β |Lamp | β |- | | Y(P,V)O<sub>4</sub>:Eu | Orange-Red |619 nm | β | β |Lamp | β |- | | YVO<sub>4</sub>:Eu | Orange-Red |619 nm | β | β |High Pressure Mercury and Metal Halide Lamps | β |- | | Y<sub>2</sub>O<sub>2</sub>S:Eu | Red |626 nm | β | β |Lamp | β |- | |3.5 [[magnesium oxide|MgO]] Β· 0.5 MgF<sub>2</sub> Β· GeO<sub>2</sub> :Mn | Red |655 nm | β | β |Lamp |3.5 [[magnesium oxide|MgO]] Β· 0.5 [[magnesium fluoride|MgF<sub>2</sub>]] Β· [[germanium dioxide|GeO<sub>2</sub>]] :Mn |- | | Mg<sub>5</sub>As<sub>2</sub>O<sub>11</sub>:Mn | Red |660 nm | β | β |High-pressure mercury lamps, 1960s | β |- | |SrAl<sub>2</sub>O<sub>7</sub>:Pb |Ultraviolet |313 nm | β | β |Special fluorescent lamps for medical use |Ultraviolet |- |CAM |LaMgAl<sub>11</sub>O<sub>19</sub>:Ce |Ultraviolet |340 nm |52 nm | β |Black-light fluorescent lamps |Ultraviolet |- |LAP |LaPO<sub>4</sub>:Ce |Ultraviolet |320 nm |38 nm | β |Medical and scientific UV lamps |Ultraviolet |- |SAC |SrAl<sub>12</sub>O<sub>19</sub>:Ce |Ultraviolet |295 nm |34 nm | β |Lamp |Ultraviolet |- | |SrAl<sub>11</sub>Si<sub>0.75</sub>O<sub>19</sub>:Ce<sub>0.15</sub>Mn<sub>0.15</sub> |Green |515 nm |22 nm | β |Lamp |Monochromatic lamps for copiers<ref>Lagos C (1974) "Strontium aluminate phosphor activated by cerium and manganese" {{US Patent|3836477}}</ref> |- |BSP |BaSi<sub>2</sub>O<sub>5</sub>:Pb |Ultraviolet |350 nm |40 nm | β |Lamp |Ultraviolet |- | |SrFB<sub>2</sub>O<sub>3</sub>:Eu(II) |Ultraviolet |366 nm | β | β |Lamp |Ultraviolet |- |SBE |SrB<sub>4</sub>O<sub>7</sub>:Eu |Ultraviolet |368 nm |15 nm | β |Lamp |Ultraviolet |- |SMS |Sr<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub>:Pb |Ultraviolet |365 nm |68 nm | β |Lamp |Ultraviolet |- | | MgGa<sub>2</sub>O<sub>4</sub>:Mn(II) |Blue-Green | β | β | β |Lamp |Black light displays |} ===Various=== Some other phosphors commercially available, for use as [[X-ray]] screens, [[neutron detector]]s, [[alpha particle]] [[scintillator]]s, etc., are: {| class="wikitable" |+ !Phosphor ![[Chemical formula|Composition]] !Color ![[Wavelength]] !Decay !Afterglow !X-ray absorption !Usage |- | |'''Gd<sub>2</sub>O<sub>2</sub>S:Eu''' |Red |627 nm |850 ΞΌs |Yes |High |X-ray, neutrons and gamma |- | |'''Gd<sub>2</sub>O<sub>2</sub>S:Pr''' |Green |513 nm |4 ΞΌs |No |High |X-ray, neutrons and gamma |- | |'''{{chem2|Gd2O2S:Pr,Ce,F}}''' |Green |513 nm |7 ΞΌs |No |High |X-ray, neutrons and gamma |- | |'''Y<sub>2</sub>O<sub>2</sub>S:Pr''' |White |513 nm |7 ΞΌs |No | |Low-energy X-ray |- |HS |'''{{chem|Zn|0.5|Cd|0.4|S:Ag}}''' |Green |560 nm |80 ΞΌs |Yes | |Efficient but low-res X-ray |- |HSr |'''{{chem|Zn|0.4|Cd|0.6|S:Ag}}''' |Red |630 nm |80 ΞΌs |Yes | |Efficient but low-res X-ray |- | |'''CdWO<sub>4</sub>''' |Blue |475 nm |28 ΞΌs |No | |Intensifying phosphor for X-ray and gamma |- | |'''CaWO<sub>4</sub>''' |Blue |410 nm |20 ΞΌs |No | |Intensifying phosphor for X-ray and gamma |- | |'''MgWO<sub>4</sub>''' |White |500 nm |80 ΞΌs |No | |Intensifying phosphor |- |YAP |'''YAlO<sub>3</sub>:Ce''' |Blue |370 nm |25 ns |No | |For electrons, suitable for photomultipliers |- |YAG |'''Y<sub>3</sub>Al<sub>5</sub>O<sub>12</sub>:Ce''' |Green |550 nm |70 ns |No | |For electrons, suitable for photomultipliers |- |YGG |'''{{chem2|Y3(Al,Ga)5O12:Ce}}''' |Green |530 nm |250 ns |Low | |For electrons, suitable for photomultipliers |- | |'''CdS:In''' |Green |525 nm |<1 ns |No | |Ultrafast, for electrons |- | |'''ZnO:Ga''' |Blue |390 nm |<5 ns |No | |Ultrafast, for electrons |- | |'''[[Anthracene]]''' |Blue |447 nm |32 ns |No | |For alpha particles and electrons |- | |plastic ('''EJ-212''') |Blue |400 nm |2.4 ns |No | |For alpha particles and electrons |- |P1 |'''Zn<sub>2</sub>SiO<sub>4</sub>:Mn''' |Green |530 nm |11 ns |Low | |For electrons |- |GS |'''ZnS:Cu''' |Green |520 nm |Minutes |Long | |For X-rays |- | |'''[[sodium iodide|NaI]]:Tl''' | | | | | |For X-ray, alpha, and electrons |- | |'''[[Caesium iodide|CsI]]:Tl''' |Green |545 nm |5 ΞΌs |Yes | |For X-ray, alpha, and electrons |- |ND |'''<sup>6</sup>[[lithium fluoride|LiF]]/ZnS:Ag''' |Blue |455 nm |80 ΞΌs | | |For [[thermal neutron]]s |- |NDg |'''{{chem2|^{6}LiF/ZnS:Cu,Al,Au}}''' |Green |565 nm |35 ΞΌs | | |For neutrons |- | |Cerium doped YAG phosphor |Yellow | | | | | |} * * * * * * * ==See also== *[[Cathodoluminescence]] *[[Laser]] *[[Luminophore]] *[[Photoluminescence]] ==References== {{reflist|30em}} ==Bibliography== *{{cite book|url=https://books.google.com/books?id=lKCWAaCiaZgC&pg=PA171|title=Luminescence and Display Phosphors: Phenomena and Applications|author=Arunachalam Lakshmanan|publisher=Nova Publishers|year=2008|isbn=978-1-60456-018-3}} ==External links== {{Wiktionary}} *[http://www.indiana.edu/~hightech/fpd/papers/ELDs.html a history of electroluminescent displays] {{Webarchive|url=https://web.archive.org/web/20120430024805/http://www.indiana.edu/~hightech/fpd/papers/ELDs.html |date=2012-04-30 }}. *[http://scienceworld.wolfram.com/physics/Fluorescence.html Fluorescence], [http://scienceworld.wolfram.com/physics/Phosphorescence.html Phosphorescence] *[https://web.archive.org/web/20040804180419/http://www.reprise.com/host/tektronix/reference/phosphor1.asp CRT Phosphor Characteristics] (P numbers) *[https://web.archive.org/web/20050221190225/http://www.geocities.com/columbiaisa/crt_phosphors.htm Composition of CRT phosphors] *[https://dx.doi.org/10.1016/j.stam.2007.08.005 Silicon-based oxynitride and nitride phosphors for white LEDsβA review] *[http://www.sphere.bc.ca/test/tube-data/rca-crt1-3.jpg] {{Webarchive|url=https://web.archive.org/web/20230410101508/http://www.sphere.bc.ca/test/tube-data/rca-crt1-3.jpg |date=2023-04-10 }} & [http://www.sphere.bc.ca/test/tube-data/rca-crt1-3a.jpg] {{Webarchive|url=https://web.archive.org/web/20230410083907/http://www.sphere.bc.ca/test/tube-data/rca-crt1-3a.jpg |date=2023-04-10 }} β RCA Manual, Fluorescent screens (P1 to P24) *[http://pt.scribd.com/doc/103757476/Inorganic-Phosphors Inorganic Phosphors Compositions, Preparation and Optical Properties, William M. Yen and Marvin J. Weber] {{Webarchive|url=https://web.archive.org/web/20160306135713/http://pt.scribd.com/doc/103757476/Inorganic-Phosphors |date=2016-03-06 }} [[Category:Luminescence]] [[Category:Lighting]] [[Category:Display technology]] [[Category:Optical materials]] [[Category:Phosphors and scintillators| ]]
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