Abstract:
Systems and methods for recovery of rare-earth constituents from environmental barrier coatings are provided. One method includes extracting rare-earth (RE) oxide constituents from a feedstock containing RE silicates and non-RE contaminants. The method includes leaching the REs from the feedstock into an acid to form an acid solution, performing an oxalate precipitation on the acid solution to form an RE oxalate hydrate, and separating the RE oxalate hydrate from the acid solution. The method also includes heat treating the RE oxalate hydrate to form an RE oxide containing the RE elements extracted from the feedstock.
Abstract:
Systems and method for filtering emissions from scintillators are provided. One system includes a scintillator having a scintillator material portion formed from a base scintillator material. The scintillator also includes a photodetector and a filter portion, The filter portion includes a material blocking near-infrared (IR) emissions. The filter portion is disposed on a surface of one of the scintillator material portion or the photodetector, and wherein the scintillator material portion, the photodetector, and the filter portion are coupled together. The filter portion blocks the near-IR emissions from impinging on the photodetector.
Abstract:
A process for synthesizing a color stable Mn4+ doped phosphor includes contacting a precursor of formula I, in gaseous form at an elevated temperature with a fluorine-containing oxidizing agent to form the color stable Mn4+ doped phosphor Ax[MFy]:Mn4+ I wherein A is Li, Na, K, Rb, Cs, NR4 or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; R is H, lower alkyl, or a combination thereof; x is the absolute value of the charge of the [MFy] ion; and y is 5, 6 or 7.
Abstract:
A process for preparing a Mn4+ doped phosphor of formula I Ax[MFy]:Mn+4 I includes contacting a mixture of a compound of formula Ax[MFy], a compound of formula AX, and a Mn+n source comprising a fluoromanganese compound, with a fluorine-containing oxidizing agent in gaseous form, at an elevated temperature, to form the Mn4+ doped phosphor; wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; X is F, Cl, Br, I, HF2, or a combination thereof; x is the absolute value of the charge of the [MFy] ion; y is 5, 6 or 7; and n is 2, 3, or 4.
Abstract:
A process for preparing a Mn4+ doped phosphor of formula I Ax[MFy]:Mn+4 I includes combining in an acidic solution, an A+ cation, an anion of formula MFy, and a Mnn+ source comprising a fluoromanganese compound, precipitating a Mnn+ containing phosphor precursor from the acidic solution, and contacting the Mnn+ containing phosphor precursor with a fluorine-containing oxidizing agent in gaseous form, at an elevated temperature, to form the Mn4+ doped phosphor; wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MFy] ion; y is 5, 6 or 7; and n is 2 or 3.
Abstract:
A process for synthesizing a color stable Mn4+ doped phosphor includes contacting a precursor of formula I, in gaseous form at an elevated temperature with a fluorine-containing oxidizing agent to form the color stable Mn4+ doped phosphor Ax[MFy]:Mn4+ wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; x is the absolute value of the charge of the [MFy] ion; and y is 5, 6 or 7.
Abstract:
A method for fabricating a light emitting device is disclosed. The light emitting device includes a light emitting diode (LED). The method includes disposing a layered phosphor composite or a thick phosphor composite radiationally coupled to the LED to form a light emitting device. The layered phosphor composite includes a first phosphor layer including a yellow-emitting phosphor over a second phosphor layer including manganese-doped potassium fluorosilicate (PFS). The second phosphor layer is disposed closer to the LED. The mass of the PFS of this light emitting device is at least 15% less than mass of the PFS in a reference light emitting device that has the same color temperature as the above mentioned light emitting device, but includes a blend of PFS and the yellow emitting phosphor instead of a layered configuration or has a decreased thickness.
Abstract:
A phosphor composition is derived from combining K2SiF6:Mn4+ in solid form with a saturated solution of a manganese-free complex fluoride including a composition of formula I: A3[MF6], where A is selected from Na, K, Rb, and combinations thereof and M is selected from Al, Ga, In, Sc, Y, Gd, and combinations thereof. The composition of formula I: A3[MF6] has a water solubility lower than a water solubility of K2SiF6. A lighting apparatus including the phosphor composition is also provided.
Abstract:
A lighting apparatus includes a semiconductor light source in direct contact with a polymer composite comprising a color stable Mn4+ doped phosphor, wherein the lighting apparatus has a color shift of 1.5 MacAdam ellipses after operating for at least 2,000 hour at a LED current density greater than 2 A/cm2, a LED wall-plug efficiency greater than 40%, and a board temperature greater than 25° C.
Abstract:
A process for preparing a Mn4+ doped phosphor of formula I Ax[MFy]:Mn+4 I includes contacting a mixture of a compound of formula Ax[MFy], a compound of formula AX, and a Mn+n source comprising a fluoromanganese compound, with a fluorine-containing oxidizing agent in gaseous form, at an elevated temperature, to form the Mn4+ doped phosphor; wherein A is Li, Na, K, Rb, Cs, or a combination thereof; M is Si, Ge, Sn, Ti, Zr, Al, Ga, In, Sc, Hf, Y, La, Nb, Ta, Bi, Gd, or a combination thereof; X is F, Cl, Br, I, HF2, or a combination thereof; x is the absolute value of the charge of the [MFy] ion; y is 5, 6 or 7; and n is 2, 3, or 4.