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In addition to these general procedures, we have developed proprietary methods and modifications to manufacture specific sulfides (binary and multinary with specific additives to modify physical characteristics) for a variety of applications including batteries, luminescent materials for displays, data storage, radiation detection, and a variety of covert/security applications.

We select the most appropriate process to meet customer requirements, and fine tune these procedures, thereby enabling processes to be operated controllably to ensure appropriate purity, stoichiometry and particle size. Our manufacturing capacity for some specialty sulfides is currently in the range of multi-ton quantities.

It is important to stress that many items are custom synthesized and, for economic reasons, we may only be able to offer these with a 1-10kg minimum order quantity. We frequently work with our customers, (always on a strictly confidential basis) to develop new products, and seamlessly implement scale-up procedures to meet their production requirements.

Sulfides are manufactured at Lorad by a wide range of methods:

Homogeneous Gas Phase reactions with volatile sulfur precursors

TiCl4 + H2S → TiS2 Titanium Disulfide, battery cathode material. Particularly useful for transition metal dichalcogenide synthesis; MS2, where M = Ta, Nb, Hf, Zr, Ti.

Gas - Solid reactions

H2S + La2O3 → La2S3, Lanthanum sulfide

H2S + 2YCl3 → Y2S3, Yttrium sulfide

CS2 + MgO → MgS, Magnesium sulfide

H2S + CoSO4 → Co9S8, Cobalt Sulfide, phase depends upon temperature Hydrodesulfurization catalyst

H2S + Ce2(CO3)3 → Ce2S3 red pigment for plastic coloring

Reactions with elemental sulfur

Cd + S → CdS, Cadmium sulfide, photoconductor

Cu + xS → Cu1.8S, Copper sulfide, glass colorant

Solution Processes

H2S + Zn(aq) → ZnS(s) , Zinc sulfide, phosphor host lattice, source for closed system vapor transport crystal growth. High index optical coating material. IR window material.

Solvated Elemental Sulfur

Sx(solv) + 2Cu(2+)aq → Cu2S

Homogeneous Precipitation

(NH2)2CS + M(n+)(aq) → MnSx (ppt), Thiourea hydrolysis

CH3CS.NH2 + M(n+)(aq) → MnSx(ppt), Thioacetamide hydrolysis

All sulfides that can be precipitated by hydrogen sulfide can similarly be precipitated by the acid or base catalysed decomposition of organosulfur reagents. This process allows us to control particle size and distribution. In some cases, with dielectric constant modification and steric control agents, we can offer nanopowders and spherical monosized powders.

Flux driven reactions

Sx + Na2CO3 → Na2Sx

Na2Sx + Gd2O3 → Gd2O2S, phosphor host lattice, Tb, Eu activated

Classical method for manufacturing oxysulfide phosphors for cathode ray tubes, Scintillators, up-converters for security and tagging operations and, x-ray phosphors.

Reduction Processes

H2 + CaSO4 → CaS Component of CaGa2S4:Eu phosphors, suitable for LED Applications. Calcium and strontium thiogallates.

Thermal decomposition of Dithiolato Complexes

In{(C2H5)2NCS2}3 → In2S3, battery, quantum dots, photovoltaic hin film component.

Many dithiolato complexes are volatile and can therefore be employed as thin film chemical vapor deposition sources. Some dithiolato complexes can be employed as aerosols for thin film deposition. It is also possible to decompose appropriate dithiolato compounds in specific solvents to generate nano-particles (Quantum dots) of sulfides such as ZnS, CdS, In2S3.

Applications assistance for dithiolato CVD source materials is available.

Non-Aqueous Solvent Routes with metal alkyls and Sulfur precursors

Ga(C2H5)3 + H2S → Ga2S3, Gallium sulfide

Zn(C2H5)2 + H2S → ZnS, Zinc sulfide. Phosphor, can be doped with Mn or rare earths, Eu, Tb.

Ceramic Method, ( High Temperature Solid State Synthesis)

CaS + La2S3 → CaLa2S4, calcium lanthanum sulfide, infrared window material

SrS + Ga2S3 → SrGa2S4, strontium gallium sulfide, excellent phosphor host lattice. Commercial quantities available as Eu activated phosphor for blue  to white LED conversion. A modified CaS.Eu red phosphor is also available in commercial quantities. These can be supplied with hydrophobic coatings.

CaS + Al2S3 → CaAl2S4, calcium aluminum sulfide, excellent green phosphor host.

Sulfidized Sol-Gel Derived Precursors

H2S + Dry Gel or low fired oxide → Sulfide. Has been used for titanium disulfide, (TiS2)synthesis.