Nanoring

The first nanorings were made of gallium nitride in 2001.{{Cite journal| vauthors = Li ZJ, Chen XL, Li HJ, Tu QY, Yang Z, Xu YP, Hu BQ |date=2001-05-01|title=Synthesis and Raman scattering of GaN nanorings, nanoribbons and nanowires|journal=Applied Physics A | volume=72 |issue=5 |pages=629–632 |doi=10.1007/s003390100796 |bibcode=2001ApPhA..72..629L|s2cid=97904274 }}

Nanorings have been prepared from zinc oxide{{cite journal | vauthors = Kong XY, Ding Y, Yang R, Wang ZL|author4-link=Zhong Lin Wang | title = Single-crystal nanorings formed by epitaxial self-coiling of polar nanobelts | journal = Science | volume = 303 | issue = 5662 | pages = 1348–51 | date = February 2004 | pmid = 14988559 | doi = 10.1126/science.1092356 | bibcode = 2004Sci...303.1348K |s2cid=17188546 }} and cyclo-para-phenylenes{{Cite journal |last1=Sicard |first1=Lambert |last2=Lucas |first2=Fabien |last3=Jeannin |first3=Olivier |last4=Bouit |first4=Pierre-Antoine |last5=Rault-Berthelot |first5=Joëlle |last6=Quinton |first6=Cassandre |last7=Poriel |first7=Cyril |date=2020-06-26 |title=[ n ]-Cyclo-9,9-dibutyl-2,7-fluorene ( n =4, 5): Nanoring Size Influence in Carbon-Bridged Cyclo- para -phenylenes |url=https://onlinelibrary.wiley.com/doi/10.1002/anie.202002517 |journal=Angewandte Chemie International Edition |language=en |volume=59 |issue=27 |pages=11066–11072 |doi=10.1002/anie.202002517 |pmid=32255247 |s2cid=215411130 |issn=1433-7851}} as well as porphyrins.{{Cite journal |last1=Casademont-Reig |first1=Irene |last2=Guerrero-Avilés |first2=Raúl |last3=Ramos-Cordoba |first3=Eloy |last4=Torrent-Sucarrat |first4=Miquel |last5=Matito |first5=Eduard |date=2021-11-02 |title=How Aromatic Are Molecular Nanorings? The Case of a Six-Porphyrin Nanoring** |journal=Angewandte Chemie International Edition |language=en |volume=60 |issue=45 |pages=24080–24088 |doi=10.1002/anie.202108997 |issn=1433-7851 |pmc=8596448 |pmid=34260804}}

Although nanorings may have a diameter on the nanoscale, many of these materials have diameters that are larger than 100 nm, with many nanorings having a diameter on the microscale (10⁻⁶ meters). As such, nanorings are considered to be members of a sub-class of nanomaterials called one-dimensional (1-D) nanomaterials. These are nanomaterials in which one of the three physical dimensions in a single unit of the material is on a length scale greater than the nanoscale. Other examples of one-dimensional nanomaterials are nanowires, nanobelts, nanotubes, and nanosheets.

As with other nanomaterials, nanorings exhibit quantized phenomena.

ZnO nanorings made from the spontaneous folding of a single nanobelt crystal can be extensively mechanically manipulated without breaking or fracturing, giving them a unique mechanical advantage over other classes of ZnO nanostructures.{{Cite journal|last1=Hughes|first1=William L.|last2=Wang|first2=Zhong L. | name-list-style = vanc |date=2005-01-19|title=Controlled synthesis and manipulation of ZnO nanorings and nanobows|journal=Applied Physics Letters|volume=86|issue=4|pages=043106|doi=10.1063/1.1853514|issn=0003-6951|bibcode=2005ApPhL..86d3106H|hdl=1853/27177 |s2cid=120864787 |hdl-access=free}}{{Cite journal|last=Wang|first=Zhong Lin | name-list-style = vanc |date=2009-04-03|title=ZnO nanowire and nanobelt platform for nanotechnology|journal=Materials Science and Engineering: R: Reports|volume=64|issue=3|pages=33–71|doi=10.1016/j.mser.2009.02.001|issn=0927-796X}}

Generally, nanorings are synthesized using a bottom-up approach, as top-down syntheses are limited by the entropic barriers presented by these materials. Currently, the number of different synthetic techniques used to make these particles is almost as diverse as the number of different types of nanorings themselves. One common method for synthesizing nanorings involves first synthesizing nanobelts or nanowires with an uneven charge distribution focused on the edges of the material. If these criteria are met, these particles may naturally self-assemble into ring structures such that Coulomb repulsion forces are minimized within the resulting crystal.{{Cite journal|last=Kong|first=X. Y.|date=2004-02-27|title=Single-Crystal Nanorings Formed by Epitaxial Self-Coiling of Polar Nanobelts|url=https://www.science.org/doi/10.1126/science.1092356|journal=Science|language=en|volume=303|issue=5662|pages=1348–1351|doi=10.1126/science.1092356|pmid=14988559 |s2cid=17188546 |issn=0036-8075}}

They cannot be grown on discrete crystal growth sites and thus, cannot be synthesized on a substrate with any crystallographic predictability.{{cite journal | vauthors = Drogat N, Granet R, Sol V, Krausz P | title = One-pot silver nanoring synthesis | journal = Nanoscale Research Letters | volume = 5 | issue = 3 | pages = 566–9 | date = December 2009 | pmid = 20672109 | pmc = 2894113 | doi = 10.1007/s11671-009-9505-5 }} Therefore, nanorings are most commonly synthesized aqueously by creating entropically unique conditions which induce spontaneous nanoring self-assembly.{{Cite journal|last1=Sprafke|first1=Johannes K.|last2=Kondratuk|first2=Dmitry V.|last3=Wykes|first3=Michael|last4=Thompson|first4=Amber L.|last5=Hoffmann|first5=Markus|last6=Drevinskas|first6=Rokas|last7=Chen|first7=Wei-Hsin|last8=Yong|first8=Chaw Keong|last9=Kärnbratt|first9=Joakim|last10=Bullock|first10=Joseph E.|last11=Malfois|first11=Marc|date=2011-11-02|title=Belt-Shaped π-Systems: Relating Geometry to Electronic Structure in a Six-Porphyrin Nanoring|url=https://pubs.acs.org/doi/10.1021/ja2045919|journal=Journal of the American Chemical Society|language=en|volume=133|issue=43|pages=17262–17273|doi=10.1021/ja2045919|pmid=21939246 |issn=0002-7863}}

Other approaches for nanoring synthesis include the assembly of a nanoring around a small seed particle which is later removed or the expansion and twisting of porphyrin-like structures into a hollow nanoring structure.{{Cite journal|last1=Miras|first1=Haralampos N.|last2=Richmond|first2=Craig J.|last3=Long|first3=De-Liang|last4=Cronin|first4=Leroy|date=2012-02-29|title=Solution-Phase Monitoring of the Structural Evolution of a Molybdenum Blue Nanoring|url=https://pubs.acs.org/doi/10.1021/ja210206z|journal=Journal of the American Chemical Society|language=en|volume=134|issue=8|pages=3816–3824|doi=10.1021/ja210206z|pmid=22257105 |issn=0002-7863}}{{Cite journal|last1=Yagi|first1=Akiko|last2=Segawa|first2=Yasutomo|last3=Itami|first3=Kenichiro|date=2012-02-15|title=Synthesis and Properties of [9]Cyclo-1,4-naphthylene: A π-Extended Carbon Nanoring|url=https://pubs.acs.org/doi/10.1021/ja300001g|journal=Journal of the American Chemical Society|language=en|volume=134|issue=6|pages=2962–2965|doi=10.1021/ja300001g|issn=0002-7863}}

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Category:Nanoparticles by morphology