Tailoring the optical gap and absorption strength of silicon quantum dots by surface modification with conjugated organic moieties
The present invention relates to semiconductor materials that include a silicon-based quantum dot; and a conjugated organic ligand connected to the silicon-based quantum dot to obtain a functionalized quantum dot. An additional aspect of the present invention is to provide methods that include providing a silicon-based quantum dot; and connecting a conjugated organic ligand connected to the silicon-based quantum dot to obtain a functionalized quantum dot.
1. A semiconductor material, comprising:
a silicon-based quantum dot; and
a conjugated organic ligand connected to the silicon-based quantum dot to obtain a functionalized quantum dot, wherein the connection between the conjugated organic ligand and the silicon-based quantum dot is a Type-II interface.
2. The semiconductor material of claim 1 , wherein the functionalized quantum dot has an organic bridge between the silicon-based quantum dot and the conjugated organic ligand, and wherein a highest occupied molecular orbital and a lowest unoccupied molecular orbital that are distributed in both the organic bridge and the silicon-based quantum dot.
3. The semiconductor material of claim 1 , wherein the Type-II interface has a conjugated vinyl connectivity.
4. The semiconductor material of claim 1 , wherein the Type-II interface reduces an optical gap of the silicon-based quantum dot.
5. The semiconductor material of claim 1 , wherein the Type-II interface has covalent bonding.
6. The semiconductor material of claim 5 , wherein the covalent bonding is through bidentate ligands.
7. The semiconductor material of claim 1 , wherein the conjugated organic ligand is a phenylimide surface ligand.
8. The semiconductor material of claim 1 , wherein the connection is a Si—C═C conjugating connection.
9. The semiconductor material of claim 1 , wherein the connection is a Si-vinyl-aromatic ligand connection.
10. The semiconductor material of claim 1 , wherein the functionalized quantum dot has a photoluminescent red shift of greater than or equal to about 20 nm.
11. The semiconductor material of claim 1 , wherein the Type-II interface has highest occupied molecular orbital localized on the conjugated organic ligand and a lowest unoccupied molecular orbital localized on the silicon-based quantum dot.
12. The semiconductor material of claim 1 , wherein the conjugated organic ligand is a 4-vinyl-N,N-bis(4-methoxyphenyl)aniline.
13. A quantum dot, comprising:
a silicon-based quantum dot; and
a conjugated organic ligand connected to the silicon-based quantum dot to obtain a functionalized quantum dot, wherein the connection between the conjugated organic ligand and the silicon-based quantum dot is a Type-II interface.
14. The quantum dot of claim 13 , wherein the functionalized quantum dot has an organic bridge between the silicon-based quantum dot and the conjugated organic ligand, and wherein a highest occupied molecular orbital and a lowest unoccupied molecular orbital that are distributed in both the organic bridge and the silicon-based quantum dot.
15. The quantum dot of claim 13 , wherein the Type-II interface has a conjugated vinyl connectivity.
16. The quantum dot of claim 13 , wherein the Type-II interface reduces an optical gap of the quantum dot.
17. A method of making a semiconductor material, comprising:
providing a silicon-based quantum dot; and
connecting a conjugated organic ligand to the silicon-based quantum dot to obtain a functionalized quantum dot, wherein the connection between the conjugated organic ligand and the silicon-based quantum dot is a Type-II interface.
18. The method of claim 17 , wherein the functionalized quantum dot has an organic bridge between the silicon-based quantum dot and the conjugated organic ligand, and wherein a highest occupied molecular orbital and a lowest unoccupied molecular orbital that are distributed in both the organic bridge and the silicon-based quantum dot.
19. The method of claim 17 , wherein the Type-II interface has a conjugated vinyl connectivity.
20. The method of claim 17 , wherein the Type-II interface reduces an optical gap of the silicon-based quantum dot.