Physical forms of MXene materials exhibiting novel electrical and optical characteristics

1. An article, comprising:

a substrate,

the substrate having disposed thereon a coating that comprises a M n+1 X n (T s ) composition having multiple layers, each layer having a first and second surface,

each layer comprising

a substantially two-dimensional array of crystal cells,

each crystal cell having an empirical formula of M n+1 X n , such that each X is positioned within an octahedral array of M,

wherein M is at least one Group 3, 4, 5, 6, or 7 metal,

wherein each X is C, N, or a combination thereof and

n=1, 2, or 3;

wherein at least one of said surfaces of the layers has surface terminations, T s , independently comprising alkoxide, alkyl, carboxylate, halide, hydroxide, hydride, oxide, sub-oxide, nitride, sub-nitride, sulfide, sulfonate, thiol, or a combination thereof,

said coating being electrically conductive and exhibiting:

(i) a resistivity in a range of from about 0.01 to about 1000 micro-ohm-meters;

(ii) an ability to transmit at least about 50% of incident light of at least one wavelength in a range of from about 300 nm to about 2000 nm

(iii) a ratio of DC conductivity, measured in Siemens/meter, to light absorbance, (including visible light absorbance), measured as a decadic absorbance per meter, of at least 0.1 Siemens measured at least one wavelength in the range of 300 to 2500 nm;

(iv) a value of the real dielectric permittivity less than negative one for wavelengths greater than a threshold wavelength; or

(v) a combination of any two or more of (i), (ii), (iii), and (iv),

wherein the substrate is comprised in a plasmonic device, wherein the plasmonic device comprises an optical-to-electrical signal transducer a surface-plasmon polariton transmitter, or an infrared-reflecting window.

2. An article, comprising:

a substrate,

the substrate having disposed thereon a coating that comprises a M n+1 X n (L) composition having multiple layers, each layer having a first and second surface,

each layer comprising

a substantially two-dimensional array of crystal cells,

each crystal cell having an empirical formula of M n+1 X n , such that each X is positioned within an octahedral array of M,

wherein M is at least one Group 3, 4, 5, 6, or 7 metal,

wherein each X is C, N, or a combination thereof and

n=1, 2, or 3;

wherein at least one of said surfaces of the layers has surface terminations, T s , independently comprising alkoxide, alkyl, carboxylate, halide, hydroxide, hydride, oxide, sub-oxide, nitride, sub-nitride, sulfide, sulfonate, thiol, or a combination thereof,

said coating being electrically conductive and exhibiting:

(i) a resistivity in a range of from about 0.01 to about 1000 micro-ohm-meters;

(ii) an ability to transmit at least about 50% of incident light of at least one wavelength in a range of from about 300 nm to about 2000 nm

(iii) a ratio of DC conductivity, measured in Siemens/meter, to light absorbance, (including visible light absorbance), measured as a decadic absorbance per meter, of at least 0.1 Siemens measured at least one wavelength in the range of 300 to 2500 nm;

(iv) a value of the real dielectric permittivity less than negative one for wavelengths greater than a threshold wavelength; or

(v) a combination of any two or more of (i), (ii), (iii), and (iv),

wherein the substrate is comprised in a metamaterial, wherein the metamaterial comprises cloaking material, transformational optic component, or a superlens.

3. The article of claim 1 , wherein the coating exhibits a resistivity in a range of from about 0.01 to about 1000 micro-ohm-meters.

4. The article of claim 1 , wherein the coating exhibits an ability to transmit at 50% of incident light of at least one wavelength in a range of from about 300 nm to about 2000 nm.

5. The article of claim 1 , wherein the coating exhibits a ratio of DC conductivity, measured in Siemens/meter, to light absorbance, (including visible light absorbance), measured as a decadic absorbance per meter, of at least 0.1 Siemens measured at at least one wavelength in the range of 300 to 2500 nm.

6. The article of claim 1 , wherein the coating exhibit a value of the real dielectric permittivity less than negative one for wavelengths greater than a threshold wavelength.

7. An article, comprising:

a substrate,

the substrate having disposed thereon a coating that comprises a M n+1 X n (T s ) composition having multiple layers, each layer having a first and second surface,

each layer comprising

a substantially two-dimensional array of crystal cells,

each crystal cell having an empirical formula of M n+1 X n , such that each X is positioned within an octahedral array of M,

wherein M is at least one Group 3, 4, 5, 6, or 7 metal,

wherein each X is C, N, or a combination thereof and

n=1, 2, or 3;

wherein at least one of said surfaces of the layers has surface terminations, T s , independently comprising alkoxide, alkyl, carboxylate, halide, hydroxide, hydride, oxide, sub-oxide, nitride, sub-nitride, sulfide, sulfonate, thiol, or a combination thereof,

said coating being electrically conductive and exhibiting:

(i) a resistivity in a range of from about 0.01 to about 1000 micro-ohm-meters;

(ii) an ability to transmit at least about 50% of incident light of at least one wavelength in a range of from about 300 nm to about 2000 nm

(iii) a ratio of DC conductivity, measured in Siemens/meter, to light absorbance, (including visible light absorbance), measured as a decadic absorbance per meter, of at least 0.1 Siemens measured at least one wavelength in the range of 300 to 2500 nm;

(iv) a value of the real dielectric permittivity less than negative one for wavelengths greater than a threshold wavelength; or

(v) a combination of any two or more of (i), (ii), (iii), and (iv),

wherein the M n+i X n (T s ) composition comprises a plurality of M n+1 X n (T s ) platelets having at least one mean lateral dimension in a range or from about 0.1 micron to about 50 microns.

8. The article of claim 1 , wherein M is at least one of Hf, Cr, Mn, Mo, Nb, Sc Ta, Ti, V, W or Zr.

9. The article of claim 1 , wherein M n+1 X n comprises Sc 2 C, Sc 2 N, Ti 2 C, Ti 2 N, V 2 C, V 2 N, Cr 2 C, Cr 2 N, Zr 2 C, Zr 2 N, Nb 2 C, Nb 2 N, Hf 2 C, Hf 2 N, Ta 2 C, Mo 2 C, Ti 3 C 2 , Ti 3 N 2 , V 3 C 2 , Ta 3 C 2 , Ta 3 N 2 , Mo 3 C 2 , (Cr 2/3 Ti 1/2 ) 3 C 2 , Ti 4 C 3 , Ti 4 N 3 , V 4 C 3 , V 4 N 3 , Ta 4 C 3 , Ta 4 N 3 , Nb 4 C 3 , or a combination thereof.

10. An article, comprising:

a substrate,

the substrate having disposed thereon a coating that comprises a M n+1 X n (T s ) composition having multiple layers, each layer having a first and second surface,

each layer comprising

a substantially two-dimensional array of crystal cells,

each crystal cell having an empirical formula of M n+1 X n , such that each X is positioned within an octahedral array of M,

wherein M is at least one Group 3, 4, 5, 6, or 7 metal,

wherein each X is C, N, or a combination thereof and

n=1, 2, or 3;

wherein at least one of said surfaces of the layers has surface terminations, T s , independently comprising alkoxide, alkyl, carboxylate, halide, hydroxide, hydride, oxide, sub-oxide, nitride, sub-nitride, sulfide, sulfonate, thiol, or a combination thereof, said coating being electrically conductive and exhibiting:

(i) a resistivity in a range of from about 0.01 to about 1000 micro-ohm-meters;

(ii) an ability to transmit at least about 50% of incident light of at least one wavelength in a range of from about 300 nm to about 2000 nm

(iii) a ratio of DC conductivity, measured in Siemens/meter, to light absorbance, (including visible light absorbance), measured as a decadic absorbance per meter, of at least 0.1 Siemens measured at least one wavelength in the range of 300 to 2500 nm;

(iv) a value of the real dielectric permittivity less than negative one for wavelengths greater than a threshold wavelength; or

(v) a combination of any two or more of (i), (ii), (iii), and (iv),

wherein M comprises at least two Group 4, 5, 6, or 7 metals, and M n+i X n (T s ) composition is represented by a formula M′ 2 M″ m X m+1 (T s ), where m=n−1,

where M′ is a first metal from Group 4, 5, 6, or 7 and where M″ is a second metal from Group 4, 5, 6, or 7.

11. The article of claim 10 , wherein M′ comprises Ti, V, Cr, or Mo.

12. The article of claim 10 , wherein M″ comprises Ti, V, Nb, or Ta, and M′ is different than M″.

13. The article of claim 10 , wherein M′ 2 M″ m X m+1 , comprises Mo 2 TiC 2 , Mo 2 VC 2 , Mo 2 TaC 2 , Mo 2 NbC 2 , Mo 2 Ti 2 C 3 , Cr 2 TiC 2 , Cr 2 VC 2 , Cr 2 TaC 2 , Cr 2 NbC 2 , Tia bC 2 , Ti 2 TaC 2 , V 2 TaC 2 , V 2 TiC 2 , or a combination thereof.

14. The article of 10 , wherein comprises M′ 2 M″ m X m+1 , comprises Mo 2 TiC 3 , Mo 2 V 2 C 3 , Mo 2 Nb 2 C 3 , Mo 2 Ta 2 C 3 , Cr 2 Ti 2 C 3 , Cr 2 V 2 C 3 , Cr 2 Nb 2 C 3 , Cr 2 Ta 2 C 3 , Nb 2 Ta 2 C 3 , Ti 2 Nb 2 C 3 , Ti 2 Ta 2 C 3 , V 2 Ta 2 C 3 , V 2 b 2 C 3 , V 2 Ti 2 C 3 , or a combination thereof.

15. The article, of claim 10 , wherein M′ 2 M″ m X m+1 , comprises Nb 2 VC 2 , Ta 2 TiC 2 , Ta 2 VC 2 , Nb 2 TiC 2 or a combination thereof.

16. The article of claim 10 , wherein the crystal cells have an empirical formula Ti 3 C 2 or Ti 2 C and wherein at least one of said surfaces of each layer is coated with surface terminations, T s , comprising alkoxide, fluoride, hydroxide, oxide, sub-oxide, sulfonate, or a combination thereof.

17. A method, wherein incident light is reflected by an article according to claim 1 .