Methods of synthesizing Bi.sub.2S.sub.3—CdS particles in the form of spheres as well as properties of these Bi.sub.2S.sub.3—CdS particles are described. Methods of photocatalytic degradation of organic pollutants employing these Bi.sub.2S.sub.3—CdS particles and methods of preventing or reducing microbial growth on a surface by applying these Bi.sub.2S.sub.3—CdS particles in the form of a solution or an antimicrobial product onto the surface are also specified.

Methods of synthesizing Bi.sub.2S.sub.3—CdS particles in the form of spheres as well as properties of these Bi.sub.2S.sub.3—CdS particles are described. Methods of photocatalytic degradation of organic pollutants employing these Bi.sub.2S.sub.3—CdS particles and methods of preventing or reducing microbial growth on a surface by applying these Bi.sub.2S.sub.3—CdS particles in the form of a solution or an antimicrobial product onto the surface are also specified.

A method is provided for producing an article which is transparent to near-wave IR, mid-wave and Long-wave multi-spectral and IR wavelength in the region of 0.4 μm to 16 μm. The method includes the steps of (a) Producing ultra-fine powder of CaLa.sub.2S.sub.4 via SPLTS process, (b) followed by pretreatment of the ultra-fine powder under inert and reducing gas conditions including H.sub.2 or Argon or N.sub.2 or H.sub.2/H.sub.2S, H.sub.2S, and mixtures there of (c) followed by sieving the powder in 140 mesh screen and cold pressing the powder at 7000 psi for 7 min. into a disk shaped green body (d) then Cold-Isostatic Pressing (CIP) at 40,000 psi for 5 min in a rubber mold (e) finally sintered article of CaLa.sub.2S.sub.4 disk of 25.4 mm diameter with ultra-high density containing cubic phase of CaLa.sub.2S.sub.4 to yield IR transmission of a peak value of 57% within the IR wavelength range of 2 μm to 16 μm, either by using microwave sintering followed by hot isostatic press or spark plasma sintering followed by hot isostatic press or vacuum sintering at (3×10.sup.−6 torr) followed by hot isostatic press or hot press sintering followed by hot isostatic press and finally followed by mirror polished IR article, is obtained.

A method is provided for producing an article which is transparent to near-wave IR, mid-wave and Long-wave multi-spectral and IR wavelength in the region of 0.4 μm to 16 μm. The method includes the steps of (a) Producing ultra-fine powder of CaLa.sub.2S.sub.4 via SPLTS process, (b) followed by pretreatment of the ultra-fine powder under inert and reducing gas conditions including H.sub.2 or Argon or N.sub.2 or H.sub.2/H.sub.2S, H.sub.2S, and mixtures there of (c) followed by sieving the powder in 140 mesh screen and cold pressing the powder at 7000 psi for 7 min. into a disk shaped green body (d) then Cold-Isostatic Pressing (CIP) at 40,000 psi for 5 min in a rubber mold (e) finally sintered article of CaLa.sub.2S.sub.4 disk of 25.4 mm diameter with ultra-high density containing cubic phase of CaLa.sub.2S.sub.4 to yield IR transmission of a peak value of 57% within the IR wavelength range of 2 μm to 16 μm, either by using microwave sintering followed by hot isostatic press or spark plasma sintering followed by hot isostatic press or vacuum sintering at (3×10.sup.−6 torr) followed by hot isostatic press or hot press sintering followed by hot isostatic press and finally followed by mirror polished IR article, is obtained.

The present disclosure is a photoelectric conversion element including: a photoelectric conversion layer 5 including a first quantum dot 4a and a second quantum dot 4b, a ratio X of the number of heavy metal atoms to the number of oxygen group atoms is less than 2 on a surface of the nanoparticle of the first quantum dot 4a, the ratio X is greater than or equal to 2 on a surface of the nanoparticle of the second quantum dot 4b, and Equation (1) is satisfied:
0.3<N  (1),
where N denotes a ratio of the number of second quantum dots to the number of first quantum dots.

The present invention is directed to methods of preparing metal sulfide, metal selenide, or metal sulfide/selenide nanoparticles and the products derived therefrom. In various embodiments, the nanoparticles are derived from the reaction between precursor metal salts and certain sulfur- and/or selenium-containing precursors each independently having a structure of Formula (I), (II), or (III), or an isomer, salt, or tautomer thereof, where Q.sup.1,Q.sup.2,Q.sup.3,R.sup.1,R.sup.2,R.sup.3,R.sup.5, and X are defined within the specification.

The present invention is directed to methods of preparing metal sulfide, metal selenide, or metal sulfide/selenide nanoparticles and the products derived therefrom. In various embodiments, the nanoparticles are derived from the reaction between precursor metal salts and certain sulfur- and/or selenium-containing precursors each independently having a structure of Formula (I), (II), or (III), or an isomer, salt, or tautomer thereof, where Q.sup.1,Q.sup.2,Q.sup.3,R.sup.1,R.sup.2,R.sup.3,R.sup.5, and X are defined within the specification.

Provided are nanoparticles passivated with a cationic metal-chalcogenide complex (MCC) and a method of preparing the same. A passivated nanoparticle includes: a core nanoparticle; and a cationic metal-chalcogenide compound (MCC) fixed on a surface of the core nanoparticle.

Provided are nanoparticles passivated with a cationic metal-chalcogenide complex (MCC) and a method of preparing the same. A passivated nanoparticle includes: a core nanoparticle; and a cationic metal-chalcogenide compound (MCC) fixed on a surface of the core nanoparticle.

A method is provided for producing an article which is transparent to IR wavelength in the region of 4 μm to 9 μm. The method includes the steps of (a) Producing ultra-fine powders of ZnS, (b) followed by pretreatment of the ultra-fine powders under reduced gas conditions including H2, H2S, N2, Ar and mixtures there of (c) followed by vacuum (3×10.sup.−6 torr) treatment to remove oxygen and sulfates adsorbed to the surface disposing a plurality of nano-particles on a substrate, wherein said nanoparticles comprise ZnS with ultra-high purity of cubic phase; (b) subjecting the nano-particles to spark plasma sintering thereby producing a sintered ZnS product with IR transmission reaching 75% in the wavelength range of 4 μm to 9 μm.