BLUE-EMITTING NANOCRYSTALS WITH CUBIC SHAPE AND GROUP IV METAL FLUORIDE PASSIVATION
This disclosure pertains to the field of nanotechnology. The disclosure provides methods of preparing nanostructures using a Group IV metal halide. The nanostructures have high quantum yield, narrow emission peak width, tunable emission wavelength, and colloidal stability. Also provided are nanostructures prepared using the methods. And, nanostructure films and molded articles comprising the nanostructures are also provided.
1 . A method of preparing the nanostructure comprising:
(a) providing a nanocrystal core;
(b) optionally admixing the core in (a) with a zinc source and a selenium source to provide a core with a ZnSe shell;
(c) admixing the core in (a) or the core with a ZnSe shell in (b) with a zinc source, a sulfur source, and at least one metal fluoride of formula (I):
MF 4 (I), wherein M=Zr, Hf, or Ti, to provide the nanostructure.
2 . The method of claim 1 , wherein the core comprises InP, InAs, ZnSe, ZnTe, or ZnSe 1-x Te x , wherein 0<x<1.
3 . The method of claim 1 , wherein the core comprises ZnSe or ZnSe 1-x Te x , wherein 0<x<1.
4 . The method of claim 1 , wherein the zinc source in (b) is selected from the group consisting of diethylzinc, dimethylzinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or mixtures thereof.
5 . The method of claim 1 , wherein the zinc source in (c) is selected from the group consisting of diethylzinc, dimethylzinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oleate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, zinc hexanoate, zinc octanoate, zinc laurate, zinc myristate, zinc palmitate, zinc stearate, zinc dithiocarbamate, or mixtures thereof.
6 . The method of claim 1 , wherein the selenium source in (b) is selected from the group consisting of tri octylphosphine selenide, tri(n-butyl)phosphine selenide, tri(sec-butyl)phosphine selenide, tri(tert-butyl)phosphine selenide, trimethylphosphine selenide, triphenylphosphine selenide, diphenylphosphine selenide, phenylphosphine selenide, tri cyclohexylphosphine selenide, cyclohexylphosphine selenide, 1-octaneselenol, 1-dodecaneselenol, selenophenol, elemental selenium, hydrogen selenide, bis(trimethylsilyl) selenide, selenourea, and combinations thereof.
7 . The method of claim 1 , wherein the sulfur source in (c) is selected from the group consisting of elemental sulfur, octanethiol, dodecanethiol, octadecanethiol, tributylphosphine sulfide, cyclohexyl isothiocyanate, a-toluenethiol, ethylene trithiocarbonate, allyl mercaptan, bis(trimethylsilyl) sulfide, trioctylphosphine sulfide, and combinations thereof.
8 . The method of claim 1 , wherein the temperature in (b) is raised, lowered, or maintained to between about 200° C. and about 310° C.
9 . The method of claim 1 , wherein the temperature in (c) is raised, lowered, or maintained to between about 280° C. and about 310° C.
10 . The method of claim 1 , wherein the nanostructure exhibits a photoluminescence quantum yield of between about 60% and about 100%.
11 . The method of claim 1 , wherein the nanostructure has a full width at half-maximum of between about 10 nm and about 40 nm.