Nanocomposite material made of a polymer-matrix comprising PEO- containing polymers and salts of luminescent polyanionic metal clusters

1. A solid nanocomposite material consisting of a polymer-matrix in which are dispersed alkali metal, hydronium or ammonium salts of polyanionic metal clusters,

wherein the alkali metal, hydronium or ammonium salts of the polyanionic metal clusters are salts or a mixture of salts of the general formula A n M 6 X i 8 L a 6 , wherein:

A represents Cs, Na, K, a hydronium or NR 1 R 2 R 3 R 4 , wherein R 1 to R 4 represent, independently of each other, a hydrogen atom or a C 1 -C 6 alkyl group;

n ranges from 2 to 5;

M represents Mo, W, Re or a mixture thereof;

X i is an inner ligand and represents a halogen atom or a mixture thereof; and

L a is an apical ligand and represents a halogen atom, an organic ligand or a mixture thereof,

wherein the polymer-matrix comprises at least a linear or branched polymer or copolymer containing one or several poly(ethylene oxide) (PEO) chains, said polymer or copolymer being optionally crosslinked and each PEO chain having at least 4 ethylene oxide monomer units, and

wherein the salts of polyanionic metal clusters interact with the polymer-matrix solely by means of weak interactions in between the alkali metal, hydronium or ammonium cation and the PEO chains of polymer or copolymer.

2. The nanocomposite material according to claim 1 , wherein:

X i represents Cl, Br, I or a mixture thereof; and

L a represents Cl, Br, I, CN, SCN, a carboxylate or a mixture thereof.

3. The nanocomposite material according to claim 1 , wherein the alkali metal, hydronium or ammonium salts of the polyanionic metal clusters are selected from the group consisting of Cs 2 Mo 6 Br 14 , Cs 2 Mo 6 Cl 14 , Cs 2 Mo 6 I 14 , Cs 2 Mo 6 Br 8 C 16 , Cs 2 Mo 6 Br 8 I 6 , Cs 2 Mo 6 I 8 (OCOC 2 F 5 ) 6 , Cs 2 Mo 6 I 8 (OCOC 3 F 7 ) 6 , (NH 4 ) 2 Mo 6 Br 8 SCN 6 , K 2 Mo 6 Cl 14 , Cs 2 W 6 I 14 , (H 3 O) 2 Mo 6 Cl 14 , (H 3 O) 2 W 6 Cl 14 and mixtures thereof.

4. The nanocomposite material according to claim 1 , wherein the polymer or copolymer is:

at least a linear PEO polymer,

at least a branched copolymer containing PEO chains grafted as side-chains onto the backbone chain of the copolymer, or

at least a linear or branched copolymer containing one or several PEO chains that are part of the backbone chain of the copolymer.

5. The nanocomposite material according to claim 1 , wherein the polymer-matrix comprises at least a linear PEO polymer, optionally with one or two identical or different light-emitting moieties grafted on its extremities.

6. The nanocomposite material according to claim 1 , wherein the polymer or copolymer is selected from the group consisting of PEO, crosslinked PEO-ureasil, crosslinked PEO-urethanesil, polymethylmethacrylate-poly(ethylene oxide) methacrylate (PMMA-PEOMA), polydimethylsiloxane-PEO (PDMS-PEO), polyvinylpyrrolidone-PEO (PVP-PEO), polyurethane-PEO (PU-PEO), polystyrene-PEO (PS-PEO), polyethylene-PEO (PE-PEO) polyester-PEO (PES-PEO), polyamide-PEO, polycaprolactone-PEO and mixtures thereof.

7. A photonic device comprising a nanocomposite material according to claim 1 .

8. The photonic device according to claim 7 , wherein it is a light-emitting diode (LED) coated with a film of the nanocomposite material.

9. A method for crop growth comprising lighting a crop with the photonic device according to claim 7 .

10. A method for emitting phosphorescence comprising irradiating the nanocomposite material according to claim 1 with a light having a wavelength in the range comprised between 340 nm and 480 nm.

11. A method for generating singlet oxygen comprising reacting the nanocomposite material according to claim 1 with triplet oxygen.

12. A process for preparing a nanocomposite material according to claim 1 , comprising a step:

of dipping the polymer-matrix in a solution containing the dissolved alkali metal, hydronium or ammonium salts of the polyanionic metal clusters, or

of polymerizing the monomer units of the polymer or copolymer as defined in claim 1 in a reaction medium containing the alkali metal, hydronium or ammonium salts of the polyanionic metal clusters, or

of crosslinking a polymer or copolymer precursor in order to obtained a crosslinked polymer or copolymer as defined in claim 1 in a reaction medium containing the alkali metal, hydronium or ammonium salts of the polyanionic metal clusters.

13. A solid nanocomposite material consisting of a polymer-matrix in which are dispersed alkali metal, hydronium or ammonium salts of polyanionic metal clusters, wherein the alkali metal, hydronium or ammonium salts of the polyanionic metal clusters are salts or a mixture of salts of the general formula A n M 6 X i 8 L a 6 , wherein:

A represents Cs, Na, K, a hydronium or NR 1 R 2 R 3 R 4 , wherein R 1 to R 4 represent, independently of each other, a hydrogen atom or a C 1 -C 6 alkyl group;

n ranges from 2 to 5;

M represents Mo, W or a mixture thereof;

X i is an inner ligand and represents a halogen or a chalcogen atom or a mixture thereof; and

L a is an apical ligand and represents a halogen atom, an organic ligand or a mixture thereof,

wherein the polymer-matrix comprises at least a linear or branched polymer or copolymer containing one or several poly(ethylene oxide) (PEO) chains, said polymer or copolymer being optionally crosslinked and each PEO chain having at least 4 ethylene oxide monomer units, and

wherein the salts of polyanionic metal clusters interact with the polymer-matrix solely by means of weak interactions in between the alkali metal, hydronium or ammonium cation and the PEO chains of polymer or copolymer.

14. The nanocomposite material according to claim 13 , wherein:

X i represents Cl, Br, I or a mixture thereof; and

L a represents Cl, Br, I, CN, SCN, a carboxylate or a mixture thereof.

15. The nanocomposite material according to claim 13 , wherein the polymer or copolymer is:

at least a linear PEO polymer,

at least a branched copolymer containing PEO chains grafted as side-chains onto the backbone chain of the copolymer, or

at least a linear or branched copolymer containing one or several PEO chains that are part of the backbone chain of the copolymer.

16. The nanocomposite material according to claim 13 , wherein the polymer-matrix comprises at least a linear PEO polymer, optionally with one or two identical or different light-emitting moieties grafted on its extremities.

17. The nanocomposite material according to claim 13 , wherein said polymer or copolymer is selected from the group consisting of PEO, crosslinked PEO-ureasil, crosslinked PEO-urethanesil, polymethylmethacrylate-poly(ethylene oxide) methacrylate (PMMA-PEOMA), polydimethylsiloxane-PEO (PDMS-PEO), polyvinylpyrrolidone-PEO (PVP-PEO), polyurethane-PEO (PU-PEO), polystyrene-PEO (PS-PEO), polyethylene-PEO (PE-PEO) polyester-PEO (PES-PEO), polyamide-PEO, polycaprolactone-PEO and mixtures thereof.

18. A process for preparing a nanocomposite material according to claim 13 , comprising a step:

of dipping the polymer-matrix in a solution containing the dissolved alkali metal, hydronium or ammonium salts of the polyanionic metal clusters, or

of polymerizing monomer units of the polymer or copolymer as defined in claim 13 in a reaction medium containing the alkali metal, hydronium or ammonium salts of the polyanionic metal clusters, or

of crosslinking a polymer or copolymer precursor in order to obtain a crosslinked polymer or copolymer as defined in claim 13 in a reaction medium containing the alkali metal, hydronium or ammonium salts of the polyanionic metal clusters.

19. A photonic device comprising a nanocomposite material according to claim 13 .

20. The photonic device according to claim 19 , wherein it is a light-emitting diode (LED) coated with a film of the nanocomposite material.

21. A method for crop growth comprising lighting a crop with the photonic device according to claim 19 .

22. A method for emitting phosphorescence comprising irradiating the nanocomposite material according to claim 13 with a light having a wavelength in the range comprised between 340 nm and 480 nm.

23. A method for generating singlet oxygen comprising reacting the nanocomposite material according to claim 13 with triplet oxygen.