Electroluminescent device and semiconductor nanoparticle

1 . A method of producing a semiconductor nanoparticle, which comprises:

combining a magnesium precursor and an additive with a chalcogen precursor in a reaction medium comprising an organic solvent and an organic ligand;

heating the reaction medium to a reaction temperature; and

reacting the magnesium precursor and the chalcogen precursor in the presence of the additive to form a magnesium chalcogenide,

wherein the semiconductor nanoparticle comprises the magnesium chalcogenide,

wherein the magnesium chalcogenide comprises

magnesium; and

selenium, sulfur, or a combination thereof,

wherein the additive comprises a potassium-containing hydride compound, an aluminum-containing hydride compound, a sodium-containing hydride compound, or a combination thereof, and

wherein the semiconductor nanoparticle further comprises an alkali metal, boron, or a combination thereof.

2 . The method of claim 1 , comprising

adding the magnesium precursor to the reaction medium simultaneously with the additive; or

adding the magnesium precursor to the reaction medium after adding the additive to the reaction medium.

3 . The method of claim 1 , wherein the hydride compound further comprises a substituted or unsubstituted C 1-50 alkyl group, boron, or a combination thereof.

4 . The method of claim 1 ,

wherein the magnesium precursor comprises a magnesium powder, an alkylated magnesium, an alkenylated magnesium, an arylated magnesium, a magnesium halide, a magnesium cyanide, a magnesium sulfate, a magnesium sulfonate, a magnesium nitrate, or a combination thereof, and

wherein the additive comprises a substituted or unsubstituted lithium trialkyl borohydride, a substituted or unsubstituted dialkyl lithium borohydride, a substituted or unsubstituted dialkyl sodium borohydride, a substituted or unsubstituted dialkyl potassium borohydride, a lithium aluminum hydride, a substituted or unsubstituted aluminum hydride, a sodium borohydride, a sodium hydride, a lithium triethylborohydride, NaBH 4 , a diisobutylaluminum hydride, or a combination thereof.

5 . The method of claim 1 , wherein the organic solvent comprises a primary amine, a secondary amine, a tertiary amine, a nitrogen-containing heterocyclic compound, a substituted or unsubstituted C 4-50 aliphatic hydrocarbon solvent, a C 6-50 substituted or unsubstituted aromatic hydrocarbon solvent, a substituted or unsubstituted phosphine solvent, a substituted or unsubstituted phosphine oxide solvent, an aromatic ether solvent, or a combination thereof, and

wherein the organic ligand comprises RCOOH, RNH 2 , R 2 NH, R 3 N, RSH, RH 2 PO, R 2 HPO, R 3 PO, RH 2 P, R 2 HP, R 3 P, ROH, RCOOR′, RPO(OH) 2 , R 2 POOH, or a combination thereof, wherein R and R′ are each independently a substituted or unsubstituted C 1-40 aliphatic hydrocarbon, a substituted or unsubstituted C 6-40 aromatic hydrocarbon, or a combination thereof.

6 . The method of claim 1 , wherein the chalcogen precursor comprises an organic solvent and selenium, an organic solvent and sulfur, a thiol compound, a bis(trialkylsilyl) alkyl sulfide, a bis(trialkylsilyl) sulfide, an ammonium sulfide, a sodium sulfide, an organic solvent and tellurium, or a combination thereof.

7 . The method of claim 1 , wherein the magnesium precursor, the chalcogen precursor, the organic ligand, and the organic solvent do not comprise an oxygen containing moiety, and optionally wherein the reaction medium does not substantially comprise an oxygen molecule.

8 . The method of claim 1 , wherein the method further comprises adding a C 6-50 aromatic phosphine compound to the reaction medium.

9 . The method of claim 1 , wherein the reaction medium further comprises a particle comprising a semiconductor nanocrystal core, and the magnesium chalcogenide is formed on a surface of the particle.

10 . The method of claim 1 , wherein the semiconductor nanocrystal core comprises a zinc chalcogenide, an indium phosphide, an indium zinc phosphide, an indium gallium phosphide, or a combination thereof.

11 . The method of claim 1 ,

wherein an amount of the additive is greater than or equal to about 0.1 moles and less than or equal to about 10 moles, per one mole of the magnesium precursor, or

wherein an amount of the chalcogen is greater than or equal to about 0.1 moles and less than or equal to about 10 moles, per one mole of the magnesium precursor.

12 . The method of claim 1 , wherein the semiconductor nanoparticle further comprises the alkali metal.

13 . The method of claim 1 , wherein in an X-ray photoelectron spectroscopy analysis of the semiconductor nanoparticle, a peak assigned to magnesium appears at a binding energy of greater than or equal to about 50 electronvolts and less than or equal to about 55 electronvolts.

14 . The method of claim 1 , wherein the method further comprises adding a zinc precursor to the reaction medium prior to initiating the reacting or during the reacting, and wherein the magnesium chalcogenide comprises a zinc magnesium chalcogenide.

15 . A semiconductor nanoparticle produced by the method of claim 1 , which comprises

a crystalline magnesium chalcogenide; and

a dopant,

wherein the dopant comprises the alkali metal, the boron, or a combination thereof,

wherein a size of the semiconductor nanoparticle is greater than or equal to about 5 nanometers and less than or equal to about 50 nanometers,

wherein the semiconductor nanoparticle does not comprise cadmium,

wherein in the semiconductor nanoparticle, a mole ratio of the dopant to the magnesium is greater than or equal to about 0.001:1 and less than or equal to about 1:1, and

wherein the semiconductor nanoparticle is configured to emit light.

16 . The semiconductor nanoparticle of claim 15 , wherein the semiconductor nanoparticle exhibits a cubic crystalline structure as determined by an X-ray diffraction analysis.

17 . The semiconductor nanoparticle of claim 15 , wherein the magnesium chalcogenide comprises a magnesium selenide, a magnesium sulfide, a magnesium telluride, a magnesium selenide sulfide, a magnesium selenide telluride, a magnesium telluride sulfide, a zinc magnesium selenide, a zinc magnesium sulfide, a zinc magnesium telluride, a zinc magnesium selenide sulfide, a zinc magnesium selenide telluride, a zinc magnesium telluride sulfide, or a combination thereof, optionally wherein in the semiconductor nanoparticle,

a mole ratio of an alkali metal or an alkaline earth metal except for magnesium to magnesium is greater than or equal to about 0.01:1 and less than or equal to about 1:1, or

a mole ratio of aluminum to magnesium is greater than or equal to about 0.01 and less than or equal to about 0.5.

18 . The semiconductor nanoparticle of claim 15 , wherein the semiconductor nanoparticle further comprises a zinc chalcogenide, and

wherein the zinc chalcogenide comprises zinc, tellurium, selenium, and optionally sulfur,

wherein in the semiconductor nanoparticle, a mole ratio of magnesium to tellurium is greater than or equal to about 1:1 and less than or equal to about 500:1, or

wherein in the semiconductor nanoparticle, a mole ratio of the dopant to tellurium is greater than or equal to about 0.1:1 and less than or equal to about 100:1.

19 . The semiconductor nanoparticle of claim 15 , wherein in an X-ray photoelectron spectroscopy analysis of the semiconductor nanoparticle, a peak assigned to magnesium appears at a binding energy of greater than or equal to about 50 electronvolts and less than or equal to about 55 electronvolts.

20 . The semiconductor nanoparticle of claim 15 , wherein the semiconductor nanoparticle comprises a semiconductor nanocrystal core and a semiconductor nanocrystal shell disposed on the semiconductor nanocrystal core, and

wherein

the semiconductor nanocrystal core comprises the magnesium chalcogenide and the dopant, and the semiconductor nanocrystal shell comprises a zinc chalcogenide, an indium phosphide, an indium gallium phosphide, or a combination thereof, or

the semiconductor nanocrystal core comprises a zinc chalcogenide, and the semiconductor nanocrystal shell comprises the magnesium chalcogenide and the dopant.

21 . An electroluminescent device comprising

a first electrode and a second electrode spaced apart from each other; and

a light emitting layer disposed between the first electrode and the second electrode,

wherein the light emitting layer comprises the semiconductor nanoparticles of claim 15 .

22 . The electroluminescent device of claim 21 , wherein the electroluminescent device further comprises a hole auxiliary layer between the light emitting layer and the first electrode, or

wherein the electroluminescent device further comprises an electron auxiliary layer between the light emitting layer and the second electrode, optionally wherein the hole auxiliary layer comprises an organic compound, the electron auxiliary layer comprises zinc magnesium metal oxide nanoparticles, or a combination thereof.

23 . A display device comprising the semiconductor nanoparticle of claim 15 .

24 . A method of producing a semiconductor nanoparticle, which comprises:

combining a magnesium precursor and an additive with a chalcogen precursor in a reaction medium comprising an organic solvent and an organic ligand;

heating the reaction medium to a reaction temperature; and

reacting the magnesium precursor and the chalcogen precursor in the presence of the additive to form a magnesium chalcogenide,

wherein the semiconductor nanoparticle comprises the magnesium chalcogenide,

wherein the magnesium chalcogenide comprises

magnesium; and

selenium, sulfur, or a combination thereof, and

wherein the additive comprises a hydride compound comprising an alkali metal, aluminum, or a combination thereof, and

wherein the semiconductor nanoparticle further comprises an alkali metal, boron, or a combination thereof.