Nanosheet

{{Short description|Extremely thin plane of material}} A '''nanosheet''' is a two-dimensional nanostructure with thickness in a scale ranging from 1 to 100&nbsp;nm.<ref>{{cite journal|title=Two-Dimensional Nanosheets Produced by Liquid Exfoliation of Layered Materials |journal=Science |year=2011|volume=331|pages=568–571|doi = 10.1126/science.1194975|pmid=21292974 |last2= Lotya|first2= M.|last3= O'Neill|first3= A.|last4= Bergin|first4= S. D.|last5= King|first5= P. J.|last6= Khan|first6= U.|last7= Young|first7= K.|last8= Gaucher|first8= A.|last9= De|first9= S.|last10=Smith |first10=R. J. |last11=Shvets |first11=I. V. |last12=Arora |first12=S. K. |last13=Stanton |first13=G. |last14=Kim |first14=H.-Y. |last15=Lee |first15=K. |last16=Kim |first16=G. T. |last17=Duesberg |first17=G. S. |last18=Hallam |first18=T. |last19=Boland |first19=J. J. |last20=Wang |first20=J. J. |last21=Donegan |first21=J. F. |last22=Grunlan |first22=J. C. |last23=Moriarty |first23=G. |last24=Shmeliov |first24=A. |last25=Nicholls |first25=R. J. |last26=Perkins |first26=J. M. |last27=Grieveson |first27=E. M. |last28=Theuwissen |first28=K. |last29=McComb |first29=D. W. |last30=Nellist |first30=P. D. |issue= 6017|last1=Coleman|first1=J. N.|display-authors=8 |bibcode=2011Sci...331..568C|hdl=2262/66458 |hdl-access=free }}</ref><ref>{{cite journal|title=Graphene nanosheet: synthesis, molecular engineering, thin film, hybrids, and energy and analytical applications |journal=Chemical Society Reviews |year=2011|volume=40|pages=2644–2672|doi =10.1039/C0CS00079E|pmid=21283849 |last2=Dong|first2=Shaojun|issue=5|last1=Guo|first1=Shaojun}}</ref><ref name="ReferenceA">{{cite journal|title=Synthesis of symmetrical hexagonal-shape PbO nanosheets using gold nanoparticles |journal=Materials Letters |year=2012|volume=67|pages=74–77|doi =10.1016/j.matlet.2011.09.048|last2=Liang|first2=Yennan|last3=Lu|first3=Haifei|last4=Wang|first4=Libo|last5=Dinh|first5=Xuan-Quyen|last6=Yu|first6=Xia|last7=Ho|first7=Ho-Pui|last8=Hu|first8=Xiao|last9=Yong|first9=Ken-Tye|last1=Zeng|first1=Shuwen|issue=1 |bibcode=2012MatL...67...74Z | url=https://www.researchgate.net/publication/257009074 }}</ref>

A typical example of a nanosheet is graphene, the thinnest two-dimensional material (0.34&nbsp;nm) in the world.<ref>{{cite journal|title=Graphene: status and prospects |journal=Science |year=2009|volume=324|pages=1530–1534|doi =10.1126/science.1158877|issue=5934|last1=Geim|first1=A. K.|pmid=19541989|arxiv=0906.3799|bibcode=2009Sci...324.1530G}}</ref><ref>{{Cite web |title=What Is the Thinnest Thing in the World? |url=https://www.acsmaterial.com/blog-detail/what-is-the-thinnest-thing-in-the-world.html?srsltid=AfmBOooBmGqfkVjfKWzEEPVQlS4k0kH_Ze2MMn39_EB0D24Ecm-3EneK |access-date=2025-12-02 |website=www.acsmaterial.com}}</ref> It consists of a single layer of carbon atoms with hexagonal lattices.

==Examples and applications== {{as of|2017}}, silicon nanosheets were being used to prototype future generations of small (5&nbsp;nm) transistors.<ref>{{Cite web|url=https://uk.pcmag.com/processors/89652/ibm-figures-out-how-to-make-5nm-chips|title=IBM Figures Out How to Make 5nm Chips|date=June 5, 2017|website=PCMag UK}}</ref>

Carbon nanosheets (from hemp) may be an alternative to graphene as electrodes in supercapacitors.<ref name=hns2014/>

Lithium Cobalt Oxide nanosheets show promise for use as cathodes in Li-ion battery applications. <ref>{{Cite journal |last=Pachuta |first=Kevin |last2=Pentzer |first2=Emily |last3=Sehirlioglu |first3=Alp |date=2020 |title=Evaluating the chemical exfoliation of lithium cobalt oxide using UV-Vis spectroscopy |url=https://pubs.rsc.org/en/content/articlelanding/2020/na/d0na00755b |journal=Nanoscale Advances |language=en |volume=2 |issue=11 |pages=5362–5374 |doi=10.1039/D0NA00755B|pmc=9419208 }}</ref><ref>{{Cite journal |last=Pachuta |first=Kevin G. |last2=Zheng |first2=Xiaoran |last3=Mofarah |first3=Sajjad S. |last4=Sorrell |first4=Charles C. |last5=Tsounis |first5=Constantine |last6=Scott |first6=Jason A. |last7=Sehirlioglu |first7=Alp |last8=Pentzer |first8=Emily B. |last9=Koshy |first9=Pramod |date=2022-11-28 |title=Engineering Multifunctional Stratified LiCoO2 Catalysts: Structural Disorder to Microstructural Exfoliation |url=https://doi.org/10.1021/acsaem.2c02846 |journal=ACS Applied Energy Materials |volume=5 |issue=11 |pages=14290–14300 |doi=10.1021/acsaem.2c02846|url-access=subscription }}</ref>

== Synthesis == right|250px|thumb|3D AFM topography image of multilayered palladium nanosheet on silicon wafer.<ref>{{cite journal|last1=Yin|first1=Xi|last2=Liu|first2=Xinhong|last3=Pan|first3=Yung-Tin|last4=Walsh|first4=Kathleen A.|last5=Yang|first5=Hong|title=Hanoi Tower-like Multilayered Ultrathin Palladium Nanosheets|journal=Nano Letters|date=November 4, 2014|doi=10.1021/nl503879a|pmid=25369350|volume=14|issue=12|pages=7188–94|bibcode=2014NanoL..14.7188Y}}</ref> The most commonly used nanosheet synthesis methods use a bottom-up approach, e.g., pre-organization and polymerization at interfaces like Langmuir–Blodgett films,<ref>{{cite journal | last1 = Payamyar | first1 = P. | last2 = Kaja | first2 = K. | last3 = Ruiz-Vargas | first3 = C. | last4 = Stemmer | first4 = A. | last5 = Murray | first5 = D. J | last6 = Johnson | first6 = C. J | last7 = King | first7 = B. T. | last8 = Schiffmann | first8 = F. | last9 = VandeVondele | first9 = J. | last10 = Renn | first10 = A. | last11 = Götzinger | first11 = S. | last12 = Ceroni | first12 = P. | last13 = Schütz | first13 = A. | last14 = Lee | first14 = L.-T. | last15 = Zheng | first15 = Z. | last16 = Sakamoto | first16 = J. | last17 = Schlüter | first17 = A. D. | year = 2014 | title = Synthesis of a Covalent Monolayer Sheet by Photochemical Anthracene Dimerization at the Air/Water Interface and its Mechanical Characterization by AFM Indentation | journal = Adv. Mater. | volume = 26 | issue = 13| pages = 2052–2058 | doi = 10.1002/adma.201304705 | pmid = 24347495 | bibcode = 2014AdM....26.2052P }}</ref> solution phase synthesis and chemical vapor deposition (CVD).<ref>{{cite journal|title=Excitation of surface electromagnetic waves in a graphene-based Bragg grating |journal=Scientific Reports |year=2012|volume=2|article-number=737 |doi =10.1038/srep00737|last2=Zeng|first2=Shuwen|last3=Shang|first3=Jingzhi|last4=Yong|first4=Ken-Tye|last5=Yu|first5=Ting|last1=Sreekanth|first1=Kandammathe Valiyaveedu|pmid=23071901|pmc=3471096|bibcode=2012NatSR...2..737S}}</ref> For example, CdTe (cadmium telluride) nanosheets could be synthesized by precipitating and aging CdTe nanoparticles in deionized water.<ref>{{cite journal|title=Self-assembly of CdTe nanocrystals into free-floating sheets |journal=Science |year=2006|volume=314|pages=274–278|doi =10.1126/science.1128045|pmid=17038616 |last2=Zhang|first2=Z.|last3=Wang|first3=Y.|last4=Glotzer|first4=S. C.|last5=Kotov|first5=N. A.|issue=5797|last1=Tang|first1=Z.|bibcode=2006Sci...314..274T}}</ref> The formation of free-floating CdTe nanosheets was due to directional hydrophobic attraction and anisotropic electrostatic interactions caused by dipole moment and small positive charges. Molecular simulations through a coarse-grained model with parameters from semi-empirical quantum mechanics calculations can be used to prove the experimental process.

Ultrathin single-crystal PbS (lead sulfur) sheets with micro scale in x-, y- dimensions can be obtained using a hot colloidal synthesis method.<ref>{{cite journal|title=Ultrathin PbS sheets by two-dimensional oriented attachment |journal=Science |year=2010|volume=329|pages=550–553|doi =10.1126/science.1188035|pmid=20671184 |last2=Juarez|first2=B. H.|last3=Pelletier|first3=M.|last4=Jander|first4=S.|last5=Greshnykh|first5=D.|last6=Nagel|first6=M.|last7=Meyer|first7=A.|last8=Foerster|first8=S.|last9=Kornowski|first9=A.|last10=Klinke |first10=C. |last11=Weller |first11=H. |issue=5991|last1=Schliehe|first1=C.|display-authors=8 |arxiv=1103.2920|bibcode=2010Sci...329..550S}}</ref> Compounds with linear chloroalkanes like 1,2-dichloroethane containing chlorine were used during the formation of PbS sheets. PbS ultrathin sheets probably resulted from the oriented attachment of the PbS nanoparticles in a two-dimensional fashion. The highly reactive facets were preferentially consumed in the growth process that led to the sheet-like PbS crystal growth.

Nanosheets can also be prepared at room temperature. For instance, hexagonal PbO (lead oxide)) nanosheets were synthesized using gold nanoparticles as seeds under room temperature.<ref name="ReferenceA"/> The size of the PbO nanosheet can be tuned by gold NPs and {{chem|Pb|2+}} concentration in the growth solution. No organic surfactants were employed in the synthesis process. Oriented attachment, in which the sheets form by aggregation of small nanoparticles that each has a net dipole moment,<ref>{{cite journal|title=Dipole-dipole interactions in nanoparticle superlattices |journal=Nano Letters |year=2007|volume=7|pages=1213–1219|doi =10.1021/nl070058c|pmid=17397231 |last2=Shevchenko|first2=Elena V.|author2-link=Elena V. Shevchenko|last3=Murray|first3=Christopher B.|last4=Titov|first4=Alexey V.|last5=Král|first5=Petr|issue=5|last1=Talapin|first1=Dmitri V.|bibcode=2007NanoL...7.1213T}}</ref><ref>{{cite journal|last1=Tang|first1=Z.|last2=Zhang|first2=Z.|last3=Wang|first3=Y.|last4=Glotzer|first4=S. C.|last5=Kotov|first5=N. A.|date=13 October 2006|title=Self-Assembly of CdTe Nanocrystals into Free-Floating Sheets|journal=Science|volume=314|issue=5797|pages=274–278|doi=10.1126/science.1128045|pmid=17038616|bibcode=2006Sci...314..274T}}</ref> and ostwald ripening<ref>{{cite journal|title=Ostwald Ripening Growth of Silicon Nitride Nanoplates |journal=Crystal Growth & Design |year=2010|volume=10|pages=29–31|doi =10.1021/cg901148q|last2=Gao|first2=Fengmei|last3=Wei|first3=Guodong|last4=An|first4=Linan|last1=Yang|first1=Weiyou |issue=1 |bibcode=2010CrGrD..10...29Y }}</ref> are the two main reasons for the formation of the PbO nanosheets. The same process was observed for iron sulfide nanoparticles.<ref>{{Cite journal|last1=Bai|first1=Yongxiao|last2=Yeom|first2=Jihyeon|last3=Yang|first3=Ming|last4=Cha|first4=Sang-Ho|last5=Sun|first5=Kai|last6=Kotov|first6=Nicholas A.|date=2013-02-14|title=Universal Synthesis of Single-Phase Pyrite FeS2 Nanoparticles, Nanowires, and Nanosheets|journal=The Journal of Physical Chemistry C|volume=117|issue=6|pages=2567–2573|doi=10.1021/jp3111106|issn=1932-7447}}</ref>

Carbon nanosheets have been produced using industrial hemp bast fibres with a technique that involves heating the fibres at over 350F (180C) for 24 hours. The result is then subjected to intense heat causing the fibers to exfoliate into a carbon nanosheet. This has been used to create an electrode for a supercapacitor with electrochemical qualities ‘on a par with’ devices made using graphene.<ref name=hns2014>{{cite web|title=Could hemp nanosheets topple graphene for making the ideal supercapacitor?|url=http://www.acs.org/content/acs/en/pressroom/newsreleases/2014/august/could-hemp-nanosheets-topple-graphene-for-making-the-ideal-supercapacitor.html |website=acs.org|publisher=American Chemistry Society |access-date=14 August 2014}}</ref>

Metal nanosheets have also been synthesized from solution-based method by reducing metal precursors, including palladium,<ref>{{cite journal|last1=Yin|first1=Xi|last2=Liu|first2=Xinhong|last3=Pan|first3=Yung-Tin|last4=Walsh|first4=Kathleen|last5=Yang|first5=Hong|title=Hanoi Tower-like Multilayered Ultrathin Palladium Nanosheets|journal=Nano Letters|date=November 4, 2014|doi=10.1021/nl503879a|pmid=25369350|volume=14|issue=12|pages=7188–94|bibcode=2014NanoL..14.7188Y}}</ref> rhodium,<ref>{{cite journal | doi = 10.1038/ncomms4093 | volume=5 | title=Ultrathin rhodium nanosheets | journal=Nature Communications | pmid=24435210 | year=2014 | article-number=3093 | last1 = Duan | first1 = H | last2 = Yan | first2 = N | last3 = Yu | first3 = R | last4 = Chang | first4 = CR | last5 = Zhou | first5 = G | last6 = Hu | first6 = HS | last7 = Rong | first7 = H | last8 = Niu | first8 = Z | last9 = Mao | first9 = J | last10 = Asakura | first10 = H | last11 = Tanaka | first11 = T | last12 = Dyson | first12 = PJ | last13 = Li | first13 = J | last14 = Li | first14 = Y| bibcode = 2014NatCo...5.3093D | doi-access = free }}</ref> and gold.<ref>{{cite journal | doi=10.1021/jp0520998 | pmid=16852818 | volume=109 | issue=30 | title=Synthesis of Single-Crystal Gold Nanosheets of Large Size in Ionic Liquids | journal=The Journal of Physical Chemistry B | pages=14445–14448| year=2005 | last1=Li | first1=Zhonghao | last2=Liu | first2=Zhimin | last3=Zhang | first3=Jianling | last4=Han | first4=Buxing | last5=Du | first5=Jimin | last6=Gao | first6=Yanan | last7=Jiang | first7=Tao }}</ref>

== See also == {{Portal|Science|Technology}} {{div col|colwidth=22em}} * Graphene * Two-dimensional polymer * Colloidal gold * Nanocrystal solar cell * Nanoparticle * Quantum dot * Langmuir–Blodgett film {{div col end}}

== References == {{reflist}}

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