p-Type transparent conducting oxides and methods for preparation
A facile, low temperature and low pressure method for the preparation of a wide range of phase pure ABO 2 compositions.
1. A low-temperature and low-pressure method of preparing phase pure p-type ABO 2 transparent conducting oxide compositions, said method comprising:
providing a basic reaction medium having a divalent A-site metal oxide reagent, a monovalent A-site metal oxide reagent, a neutral B-site metal reagent and a trivalent B-site metal oxide reagent, said A-site metal of said monovalent and divalent A-site metal oxide reagents selected from the group consisting of Cu, Pt, Pd, Ag and combinations thereof;
introducing water to said reaction medium;
heating said rection medium at a temperature substantially less than 500° C. and a pressure substantially less than 3000 atm; and
isolating a phase pure p-type ABO 2 transparent conducting oxide composition.
2. The method of claim 1 wherein said reaction medium temperature is increased.
3. The method of claim 2 wherein said reaction medium temperature is about 150° C., then increased to about 215° C.
4. The method of claim 1 wherein water is introduced to said reaction medium using a water-permeable vessel.
5. The method of claim 1 wherein said ABO 2 composition has a delafossite structure comprising a monovalent metal cation A and a trivalent metal cation B.
6. The method of claim 5 wherein said metal cation A is Cu and said composition is CuBO 2 .
7. The method of claim 6 wherein said metal cation B has an ionic radius dimension between the ionic radial dimension of Al +3 and the ionic radial dimension of La +3 .
8. The method of claim 5 wherein said metal cation A is Ag and said composition is AgBO 2 .
9. The method of claim 8 wherein said metal cation B has an ionic radius dimension between the ionic radial dimension of Al +3 and the ionic radial dimension of La +3 .
10. The method of claim 5 wherein said metal cation A is Pd and said composition is PdBO 2 .
11. The method of claim 10 wherein said metal cation B has an ionic radius dimension between the ionic radial dimension of Al +3 and the ionic radial dimension of La +3 .
12. The method of claim 5 wherein said metal cation A is Pt and said composition is PtBO 2 .
13. The method of claim 12 wherein said metal cation B has an ionic radius dimension between the ionic radial dimension of Al +3 and the ionic radial dimension of La +3 .
14. The method of claim 1 wherein said composition is a polycrystalline A 1-m A m B 1-n B n O 2 solid solution, wherein each of A and A′ are A-site cationic metal species selected from Cu, Pd, Pt and Ag, and each of B and B′ are B-site cationic metal species selected from Al, Ga, Sc, In and lanthanide series metals, 0<m<1 and 0<n<1.
15. The method of claim 14 wherein said A-site metal is Cu and said composition is CuAl 1-n Ga n O 2 .
16. A low-temperature and low-pressure method of preparing phase pure p-type ABO 2 transparent conducting oxide compositions, said method comprising:
providing a basic reaction medium having a divalent A-site metal oxide reagent, a monovalent A-site metal oxide reagent, a neutral B-site metal reagent and a trivalent B-site metal oxide reagent, said A-site metal of said monovalent and divalent A-site metal oxide reagents selected from the group consisting of Cu, Pt, Pd, Ag and combinations thereof;
introducing water to said reaction medium
heating said reaction medium at a temperature less than about 250° C. and a pressure less than about 20 atm; and
isolating a phase pure p-type ABO 2 transparent conducting oxide composition.
17. The method of claim 16 wherein said reaction medium temperature is increased.
18. The method of claim 17 wherein said reaction medium temperature is about 150° C., then increased to about 215° C.
19. The method of claim 16 wherein water is introduced to said reaction medium using a water-permeable vessel.
20. The method of claim 16 wherein said ABO 2 composition has a delafossite structure comprising a monovalent metal cation A and a trivalent metal cation B selected from the group consisting of metal cations having an ionic radius dimension between the ionic radial dimension of A +3 and the ionic radial dimension of La +3 .