Metallic Dispersion
A compound film may be formed by formulating a mixture of elemental nanoparticles composed of the Ib, the IIIa, and, optionally, the VIa group of elements having a controlled overall composition. The nanoparticle mixture is combined with a suspension of nanoglobules of gallium to form a dispersion. The dispersion may be deposited onto a substrate to form a layer on the substrate. The layer may then be reacted in a suitable atmosphere to form the compound film. The compound film may be used as a light-absorbing layer in a photovoltaic device.
1 . A semiconductor film made by a process comprising:
formulating a dispersion of nanoparticles of the Ib, the IIIa, and, optionally, the VIa group of elements, depositing said dispersion onto a substrate to form a layer on the substrate, and reacting the layer in a suitable atmosphere to form said compound film, wherein said compound film has a Cu/(In+Ga) compositional range of about 0.01 to about 1.0 and a Ga/(In+Ga) compositional range of about 0.01 to about 1.0.
2 . A photovoltaic device having a light-absorbing layer containing elements of groups Ib, IIIa and VIa, wherein the light-absorbing layer is formed from a compound film deposited on a substrate by the process of claim 1 .
3 . The process of claim 1 , wherein said nanoparticles are solid-particulates.
4 . The process of claim 1 , wherein said dispersion nanoparticles includes at least one element from the group consisting of: aluminum, tellurium, or sulfur.
5 . The process of claim 1 , wherein one or more classes of said nanoparticles are doped with one or more inorganic materials.
6 . The process of claim 5 , wherein the inorganic materials are chosen from the group of aluminum (Al), sulfur (S), sodium (Na), potassium (K), or lithium (Li).
7 . The process of claim 1 wherein depositing includes using at least one method from the group consisting of: dip coating, spin coating, web coating, doctor blade coating, cup coating, spray coating, printing, microgravure, reverse microgravure, comma, slot/die coating, lip coating, and the like.
8 . The process of claim 1 wherein the substrate is flexible.
9 . The process of claim 1 wherein e substrate is a plastic foil, or a metallized plastic foil.
10 . The process of claim 9 wherein the substrate is selected from the group consisting of: stainless steel, Al, Mo, and Ti.
11 . The process of claim 9 further comprising a contact layer comprised of a different metal than the substrate and disposed between the substrate and the film.
12 . The process of claim 9 wherein the contact layer comprises molybdenum.
13 . The process of claim 9 further comprising depositing a window layer on the semiconductor film.
14 . The process of claim 13 wherein the window layer comprises of a material selected from the group consisting of: cadmium sulfide (CdS), zinc sulfide (ZnS), zinc hydroxide, zinc selenide (ZnSe), n-type organic materials, or some combination of two or more of these or similar materials.
15 . The process of claim 1 wherein reacting occurs during the annealing step.
16 . The process of claim 1 wherein reacting occurs after the annealing step.
17 . The process of claim 1 wherein reacting occurs in a suitable atmosphere that contains at least one from the group consisting of: selenium, sulfur, or tellurium, and/or hydride gases comprising Se and/or S and/or Te, or mixtures of these gases.