Editing Tellurium (section)

==Applications==
In 2022, the major applications of tellurium were [[thin-film solar cell]]s (40%), [[thermoelectrics]] (30%), metallurgy (15%), and rubber (5%), with the first two applications experiencing a rapid increase owing to the worldwide tendency of reducing dependence on the [[fossil fuel]].<ref name=usgs/><ref name=usgs2/> In metallurgy, tellurium is added to [[iron]], [[stainless steel]], [[copper]], and lead alloys. It improves the machinability of copper without reducing its high electrical conductivity. It increases resistance to vibration and fatigue of lead and stabilizes various carbides and in malleable iron.<ref name=usgs2/>

===Heterogeneous catalysis===
Tellurium oxides are components of commercial oxidation catalysts. Te-containing catalysts are used for the [[ammoxidation]] route to [[acrylonitrile]] (CH<sub>2</sub>=CH–C≡N):<ref name="UllTe">{{Ullmann|doi=10.1002/14356007.a26_177|title=Tellurium and Tellurium Compounds|year=2000|last1=Knockaert|first1=Guy|isbn=3527306730}}</ref>

{{block indent|2&nbsp;CH<sub>3</sub>−CH{{=}}CH<sub>2</sub> + 2&nbsp;NH<sub>3</sub> + 3&nbsp;O<sub>2</sub> → 2&nbsp;CH<sub>2</sub>{{=}}CH–C≡N + 6&nbsp;H<sub>2</sub>O}}

Related catalysts are used in the production of [[tetramethylene glycol]]:
{{block indent|CH<sub>3</sub>CH<sub>2</sub>CH<sub>2</sub>CH<sub>3</sub> + O<sub>2</sub> → HOCH<sub>2</sub>CH<sub>2</sub>CH<sub>2</sub>CH<sub>2</sub>OH}}

===Niche===
[[File:NREL Array.jpg|thumb|alt=Solar panels, angled at about 30 degrees, reflect the blue sky from above a grassy field.|A [[Cadmium telluride|CdTe]] [[photovoltaic array]]]]
*Synthetic rubber vulcanized with tellurium shows mechanical and thermal properties that in some ways are superior to [[sulfur vulcanization|sulfur-vulcanized]] materials.<ref>{{Cite book|chapter-url = https://books.google.com/books?id=vGl4yg2Xg0YC&pg=PA42| isbn = 978-0-412-53950-3|page = 42|chapter = Sulfur and Related Elements|publisher = Springer|date = 1987|title = Rubber Technology|first = Maurice|last = Morton}}</ref><ref name="UllTe" />
* Tellurium compounds are specialized pigments for [[ceramic]]s.<ref name="CRC" />
* Selenides and tellurides greatly increase the optical refraction of glass widely used in [[Optical fiber|glass optical fibers]] for telecommunications.<ref>{{Cite journal|doi =10.1016/S0022-3093(05)80767-7|title =Recent advances and trends in chalcogenide glass fiber technology: a review|date =1992|last1 =Nishii|first1 =J.|last2 =Morimoto|first2 =S.|last3 =Inagawa|first3 =I.|last4 =Iizuka|first4 =R.|last5 =Yamashita|first5 =T.|last6 =Yamagishi|first6 =T.|journal =Journal of Non-Crystalline Solids|volume =140|pages =199–208|bibcode=1992JNCS..140..199N}}</ref><ref>{{Cite book|url =https://books.google.com/books?id=BAEnBr6ncmEC&pg=PA1|isbn = 978-0-8493-0368-5|pages =1–11|title = Tellurite glasses handbook: physical properties and data|publisher = CRC Press|date = 2002|first = Raouf A. H.|last = El-Mallawany}}</ref>
* Mixtures of selenium and tellurium are used with [[barium peroxide]] as an oxidizer in the delay powder of electric [[blasting cap]]s.<ref>{{Cite journal|doi = 10.1021/ie50610a035|title = Correspondence. Representing Delay Powder Data.|date = 1960|last1 = Johnson|first1 = L. B.|journal = Industrial & Engineering Chemistry|volume = 52|pages = 868|issue = 10}}</ref>
* [[Neutron]] bombardment of tellurium is the most common way to produce [[iodine-131]].<ref>[http://www.nordion.com/wp-content/uploads/2014/10/MI_Iodine-131_Solution_Canada.pdf Iodine-131 (n, gamma) Radiochemical Sodium Iodide Solution]. nordion.com</ref> This in turn is used to treat some [[thyroid]] conditions, and as a tracer compound in [[hydraulic fracturing]], among other applications.

=== Semiconductor and electronic ===
[[File:NuSTAR detector.JPG|thumb|A [[Cadmium zinc telluride|(Cd,Zn)Te]] detector from the [[NuSTAR]] NASA X-ray telescope]]
[[File:Swift's instrument Burst Alert Telescope (BAT) the detector plane.jpg|thumb|An array of (Cd,Zn)Te X-ray detectors from the Burst Alert Telescope of the NASA [[Neil Gehrels Swift Observatory]]]]
[[Cadmium telluride]] (CdTe) [[Photovoltaic module|solar panels]] exhibit some of the greatest efficiencies for solar cell electric power generators.<ref>{{Cite journal| doi = 10.1126/science.1189690|title = The Impact of Tellurium Supply on Cadmium Telluride Photovoltaics|date = 2010|last1 = Zweibel|first1 = K.|journal = Science|volume = 328|pages = 699–701|pmid = 20448173|issue = 5979|bibcode = 2010Sci...328..699Z |s2cid = 29231392}}</ref>

In 2018, China installed thin-film solar panels with a total power output of 175 GW, more than any other country in the world; most of those panels were made of CdTe.<ref name=usgs2/> In June 2022, China set goals of generating 25% of energy consumption and installing 1.2 billion kilowatts of capacity for wind and solar power by 2030. This proposal will increase the demand for tellurium and its production worldwide, especially in China, where the annual volumes of Te refining increased from 280 tonnes in 2017 to 340 tonnes in 2022.<ref name=usgs/>

{{chem2|[[Cadmium zinc telluride|(Cd,Zn)Te]]}} is an efficient material for detecting [[X-ray]]s.<ref>{{Cite book|chapter-url = https://books.google.com/books?id=cWj_eunQr7kC&pg=PA87|isbn = 978-0-387-95021-1|chapter = Cadmium zinc telluride detector |pages = 87–88|author = Saha, Gopal B.|date = 2001|publisher = Springer|location = New York|title = Physics and radiobiology of nuclear medicine}}</ref> It is being used in the NASA space-based X-ray telescope [[NuSTAR]].

[[HgCdTe|Mercury cadmium telluride]] is a [[semiconductor]] material that is used in thermal imaging devices.<ref name=usgs2/>

===Organotellurium compounds===
{{main|Organotellurium chemistry}}
Organotellurium compounds are mainly of interest in the research context. Several have been examined such as precursors for [[metalorganic vapor phase epitaxy]] growth of II-VI [[compound semiconductor]]s. These precursor compounds include [[dimethyl telluride]], diethyl telluride, diisopropyl telluride, diallyl telluride, and methyl allyl telluride.<ref>{{Cite book|isbn = 978-0-7923-7206-6|chapter-url = https://books.google.com/books?id=HtgEcjQcgkkC&pg=PA265|chapter = Metalorganic vapour phase epitaxy|pages =265–267|editor=Capper, Peter|editor2=Elliott, C. T.|date = 2001|publisher = Kluwer Academic|location = Boston, Mass.|title = Infrared detectors and emitters : materials and devices}}</ref> Diisopropyl telluride (DIPTe) is the preferred precursor for low-temperature growth of CdHgTe by [[MOVPE]].<ref>{{Cite journal|title = Ultra-pure organotellurium precursors for the low-temperature MOVPE growth of II/VI compound semiconductors|doi = 10.1016/0022-0248(88)90613-6|journal = Journal of Crystal Growth|volume = 93|date = 1988|pages = 744–749|last1 = Shenai-Khatkhate|first1 = Deodatta V.|issue =1–4|bibcode = 1988JCrGr..93..744S|last2 = Webb|first2 = Paul|last3 = Cole-Hamilton|first3 = David J.|last4 = Blackmore|first4 = Graham W.|last5 = Brian Mullin|first5 = J. }}</ref> The greatest purity [[metalorganics]] of both [[selenium]] and tellurium are used in these processes. The compounds for semiconductor industry and are prepared by [[adduct purification]].<ref>{{Cite journal|title = Organometallic Molecules for Semiconductor Fabrication [and Discussion]|first6 = P.|last6 = Day|first5 = D. J.|last5 = Cole-Hamilton|first4 = J. B.|last4 = Mullin|first3 = A. E. D.|last3 = McQueen|doi = 10.1098/rsta.1990.0011|first2 = M. B.|journal = Phil. Trans. R. Soc. Lond. A|volume = 330|last2 = Parker|date = 1990|pages = 173–182|last1 = Shenai-Khatkhate|first1 = Deodatta V.|issue =1610|bibcode = 1990RSPTA.330..173S |s2cid = 100757359}}</ref><ref>Mullin, J.B.; Cole-Hamilton, D.J.; Shenai-Khatkhate, D.V.; Webb P. (May 26, 1992) {{US patent|5117021}} "Method for purification of tellurium and selenium alkyls"</ref>

[[Tellurium suboxide]] is used in the media layer of rewritable [[optical disc]]s, including [[CD-RW|ReWritable Compact Discs]] ([[CD-RW]]), ReWritable Digital Video Discs ([[DVD-RW]]), and ReWritable [[Blu-ray Disc]]s.<ref>{{Cite web|url = https://www.engadget.com/2006/10/19/panasonic-says-that-its-100gb-blu-ray-discs-will-last-a-century/|title = Panasonic says that its 100GB Blu-ray discs will last a century|access-date = 2008-11-13|first = Cyrus|last = Farivar|date =2006-10-19}}</ref><ref>{{Cite journal|journal = Japanese Journal of Applied Physics|volume = 37|issue = 4B|date = 1998|pages = 2163–2167|title = Dual-Layer Optical Disk with Te–O–Pd Phase-Change Film|author = Nishiuchi, Kenichi|author2 = Kitaura, Hideki|author3 = Yamada, Noboru|author4 = Akahira, Nobuo|doi = 10.1143/JJAP.37.2163|bibcode = 1998JaJAP..37.2163N| s2cid=119849468 }}</ref>

Tellurium is used in the [[phase change memory]] chips<ref>{{Cite journal|title = Overview of Phase-Change Chalcogenide Nonvolatile Memory Technology|first =S.|last = Hudgens|author2=Johnson, B. | volume = 29|issue = 11|pages = 829–832|date = 2004|journal = MRS Bulletin|doi = 10.1557/mrs2004.236|s2cid =137902404}}
</ref> developed by [[Intel]].<ref>{{Cite journal| journal = IEEE Spectrum|volume =40|issue = 3|date = 2003|pages = 48–54|doi = 10.1109/MSPEC.2003.1184436|title = The New Indelible Memories|first = Linda|last = Geppert}}</ref> [[Bismuth telluride]] (Bi<sub>2</sub>Te<sub>3</sub>) and [[lead telluride]] are working elements of [[thermoelectric]] devices. [[Lead telluride]] exhibits promise in far-[[infrared]] detectors.<ref name=usgs2/>

=== Photocathodes ===
Tellurium shows up in a number of [[photocathode]]s used in solar blind [[photomultiplier tube]]s<ref>{{Cite journal|last1=Taft|first1=E.|last2=Apker|first2=L.|date=1953-02-01|title=Photoemission from Cesium and Rubidium Tellurides|url=https://www.osapublishing.org/josa/abstract.cfm?uri=josa-43-2-81|journal=JOSA|language=EN|volume=43|issue=2|pages=81–83|doi=10.1364/JOSA.43.000081|bibcode=1953JOSA...43...81T}}</ref> and for high brightness [[photoinjector]]s driving modern particle accelerators. The photocathode Cs-Te, which is predominantly Cs<sub>2</sub>Te, has a photoemission threshold of 3.5 eV and exhibits the uncommon combination of high quantum efficiency (>10%) and high durability in poor vacuum environments (lasting for months under use in RF electron guns).<ref>[[Triveni Rao|Rao, T.]], & Dowell, D. H. (2013). ''An engineering guide to photoinjectors''. CreateSpace Independent Publishing.</ref>  This has made it the go to choice for photoemission electron guns used in driving [[Free-electron laser|free electron lasers]].<ref>LCLS-II Project Team. (2015). [https://portal.slac.stanford.edu/sites/ard_public/people/tora/Temp/150921%20LCLS-II%20FDR.pdf ''LCLS-II Final Design Report'']. (LCLSII-1.1-DR-0251-R0). SLAC.</ref>  In this application, it is usually driven at the wavelength 267&nbsp;nm which is the third harmonic of commonly used [[Ti-sapphire laser]]s. More Te containing photocathodes have been grown using other alkali metals such as rubidium, Potassium, and Sodium, but they have not found the same popularity that Cs-Te has enjoyed.<ref>{{Cite patent|title=Bi-alkali telluride photocathode|gdate=1978-07-20|country=US|number=4196257|pubdate=1980-04-01|assign=[[RCA Corporation]]|inventor1-last=Engstrom |inventor1-first=Ralph W. |inventor2-last=McDonie |inventor2-first=Arthur F.}}</ref><ref>Trautner, H. (2000). ''Spectral Response of Cesium Telluride and Rubidium Telluride Photocathodes for the Production of Highly Charged Electron Bunches''. CERN.</ref>

=== Thermoelectric material ===
Tellurium itself can be used as a high-performance elemental thermoelectric material. A trigonal Te with the space group of P3<sub>1</sub>21 can transfer into a topological insulator phase, which is suitable for thermoelectric material. Though often not considered as a thermoelectric material alone, polycrystalline tellurium does show great thermoelectric performance with the thermoelectric figure of merit, zT, as high as 1.0, which is even higher than some of other conventional TE materials like SiGe and BiSb.<ref>{{Cite journal |last1=Lin |first1=Siqi |last2=Li |first2=Wen |last3=Chen |first3=Zhiwei |last4=Shen |first4=Jiawen |last5=Ge |first5=Binghui |last6=Pei |first6=Yanzhong |date=2016-01-11 |title=Tellurium as a high-performance elemental thermoelectric |journal=Nature Communications |language=en |volume=7 |issue=1 |pages=10287 |doi=10.1038/ncomms10287 |pmid=26751919 |pmc=4729895 |bibcode=2016NatCo...710287L |issn=2041-1723}}</ref>

Telluride, which is a compound form of tellurium, is a more common TE material. Typical and ongoing research includes Bi<sub>2</sub>Te<sub>3</sub>, and La<sub>3−x</sub>Te<sub>4</sub>, etc. Bi<sub>2</sub>Te<sub>3</sub> is widely used from energy conversion to sensing to cooling due to its great TE properties. The BiTe-based TE material can achieve a conversion efficiency of 8%, an average zT value of 1.05 for p-type and 0.84 for n-type bismuth telluride alloys.<ref>{{Cite journal |last1=Nozariasbmarz |first1=Amin |last2=Poudel |first2=Bed |last3=Li |first3=Wenjie |last4=Kang |first4=Han Byul |last5=Zhu |first5=Hangtian |last6=Priya |first6=Shashank |date=2020-07-24 |title=Bismuth Telluride Thermoelectrics with 8% Module Efficiency for Waste Heat Recovery Application |journal=iScience |language=en |volume=23 |issue=7 |pages=101340 |doi=10.1016/j.isci.2020.101340 |pmid=32688286 |pmc=7369584 |bibcode=2020iSci...23j1340N |issn=2589-0042}}</ref> Lanthanum telluride can be potentially used in deep space as a thermoelectric generator due to the huge temperature difference in space. The zT value reaches to a maximum of ~1.0 for a La<sub>3−x</sub>Te<sub>4</sub> system with x near 0.2. This composition also allows other chemical substitution which may enhance the TE performance. The addition of Yb, for example, may increase the zT value from 1.0 to 1.2 at 1275K, which is greater than the current SiGe power system.<ref>{{Cite journal |last1=May |first1=Andrew |last2=Snyder |first2=Jeff |last3=Fleurial |first3=Jean-Pierre |last4=El-Genk |first4=Mohamed S. |date=2008 |title=Lanthanum Telluride: Mechanochemical Synthesis of a Refractory Thermoelectric Material |url=http://aip.scitation.org/doi/abs/10.1063/1.2845029 |journal=AIP Conference Proceedings |language=en |location=Albuquerque (New Mexico) |publisher=AIP |volume=969 |pages=672–678 |doi=10.1063/1.2845029|bibcode=2008AIPC..969..672M }}</ref>