Fabrication of electrically active films based on multiple layers

Abstract

A continuous film of desired electrical characteristics is obtained by successively printing and annealing two or more dispersions of prefabricated nanoparticles.

1 . A flowable printing composition comprising a carrier and a dispersion of nanoparticles therein, the nanoparticles comprising first and second components, the first component comprising at least one of Cu or Ag, and the second component comprising at least one of Se, Te, or S, the composition having a viscosity substantially independent of flow rate. 
   
   
       2 . The printing composition of  claim 1 , wherein the first component comprises Cu or Ag, but not both. 
   
   
       3 . The printing composition of  claim 1 , wherein the second component comprises exactly one of the elements Se, Te, or S. 
   
   
       4 . The printing composition of  claim 1 , wherein the nanoparticles comprise a third component comprising at least one of In, Ga, or Al. 
   
   
       5 . The printing composition of  claim 4 , wherein the nanoparticles have the formula CuIn 1-x Ga x Se 2  where x varies between 1 and 0. 
   
   
       6 . The printing composition of  claim 1 , wherein the composition is adapted for use in a printing method selected from the group consisting of inkjet printing, pneumatic spraying, screen printing, pad printing, laser printing, dot matrix printing, thermal printing, lithography and 3D printing. 
   
   
       7 . The printing composition of  claim 1 , wherein the nanoparticles have an average size not greater than 20 nm. 
   
   
       8 . The printing composition of  claim 1 , wherein the nanoparticles have a size dispersity of ±2 nm or less. 
   
   
       9 . The printing composition of  claim 1 , wherein the carrier comprises at least one of a solvent or a dispersing agent. 
   
   
       10 . The printing composition of  claim 9 , wherein the solvent is an organic solvent. 
   
   
       11 . The printing composition of  claim 10 , wherein the solvent is toluene. 
   
   
       12 . The printing composition of  claim 1 , wherein the dispersion has a form selected from the group consisting of a solution, a colloid and a suspension. 
   
   
       13 . The printing composition of  claim 1 , wherein the composition has a viscosity in the range from 0.158×10 11  cP to 2.3×10 11  cP. 
   
   
       14 . The printing composition of  claim 1 , wherein the nanoparticles are coated with a capping agent. 
   
   
       15 . The printing composition of  claim 14 , wherein the capping agent is a water solubilising capping agent. 
   
   
       16 . The printing composition of  claim 14 , wherein the capping agent is mercaptoacetic acid. 
   
   
       17 . A flowable printing composition comprising a carrier and a dispersion of nanoparticles therein, the nanoparticles each comprising first, second, and third components, the first component comprising at least one of Cu or Ag, the second component comprising at least one of Se, Te, or S, and the third component comprising at least one of In, Ga, or Al, the composition having a viscosity substantially independent of flow rate. 
   
   
       18 . The printing composition of  claim 17 , wherein the first component comprises Cu or Ag, but not both. 
   
   
       19 . The printing composition of  claim 17 , wherein the second component comprises exactly one of the elements Se, Te, or S.