Multiple band gap Co-Ni oxide compositions and applications thereof
In one aspect, metal oxide compositions having electronic structure of multiple band gaps are described. In some embodiments, a metal oxide composition comprises a (Co,Ni)O alloy having electronic structure including multiple band gaps. The (Co,Ni)O alloy can include a first band gap and a second band gap, the first band gap separating valence and conduction bands of the electronic structure.
1. A metal oxide composition comprising:
a (Co,Ni)O alloy having electronic structure including multiple band gaps, wherein Co and Ni are each in the 2 + oxidation state.
2. The metal oxide composition of claim 1 , wherein the (Co,Ni)O alloy includes a first band gap and a second band gap, the first band gap separating valence and conduction bands of the electronic structure.
3. The metal oxide composition of claim 2 , wherein the conduction band comprises a first band and a second band.
4. The metal oxide composition of claim 3 , wherein the first band and the second band are separated by at least 0.2 eV.
5. The metal oxide composition of claim 3 , wherein the first band and the second band are separated by 0.2-0.7 eV.
6. The metal oxide composition of claim 3 , wherein the first band has a width of at least 0.8 eV.
7. The metal oxide composition of claim 3 , wherein the first band has a width of 0.8-1.5 eV.
8. The metal oxide composition of claim 3 , wherein the second band has a width of at least 0.4 eV.
9. The metal oxide composition of claim 3 , wherein the second band has a width of 0.5-1.0 eV.
10. The metal oxide composition of claim 1 , wherein the (Co,Ni)O alloy is of the formula Co x Ni 1-x O with 0.2≤x≤0.3.
11. The metal oxide composition of claim 10 , wherein 0.23≤x≤0.27.
12. The metal oxide composition of claim 10 , wherein x=0.25.
13. The metal oxide composition of claim 1 , wherein the (Co,Ni)O alloy is of the formula Co x Ni 1-x O with 0.125<x<0.375.
14. The metal oxide composition of claim 1 , wherein the (Co,Ni)O alloy comprises one or more dopants.
15. The metal oxide composition of claim 14 , wherein the doped (Co,Ni)O alloy exhibits p-type character.
16. The metal oxide composition of claim 14 , wherein the doped (Co,Ni)O alloy exhibits n-type character.
17. The metal oxide composition of claim 14 , wherein the one or more dopants are selected from the group consisting of alkali metals, alkaline earth metals, transition metals and Lanthanide series metals.
18. The metal oxide composition of claim 1 having photonic emission of varying wavelengths.
19. A solar cell comprising:
a photosensitive region, the photosensitive region comprising a (Co,Ni)O alloy having electronic structure including multiple band gaps, wherein Co and Ni are each in the 2 + oxidation state.
20. A light emitting diode comprising:
a light emitting region, the light emitting region comprising a (Co,Ni)O alloy having electronic structure including multiple band gaps, wherein Co and Ni are each in the 2 + oxidation state.
21. The metal oxide composition of claim 1 , wherein the (Co,Ni)O alloy has cubic crystalline structure.
22. The solar cell of claim 19 , wherein the (Co,Ni)O alloy has cubic crystalline structure.
23. The light emitting diode of claim 20 , wherein the (Co,Ni)O alloy has cubic crystalline structure.
24. A metal oxide composition comprising:
a (Co,Ni)O alloy having electronic structure including multiple band gaps, wherein the (Co,Ni)O alloy has cubic crystalline structure.