CONDUCTIVE NANOPARTICLE INKS AND PASTES AND APPLICATIONS USING THE SAME

1 . A method comprising:

(a) providing a first mixture comprising at least one nanoparticle precursor and at least one first solvent for the nanoparticle precursor, wherein the nanoparticle precursor comprises a salt comprising a cation comprising a metal;

(b) providing a second mixture comprising at least one reactive moiety reactive for the nanoparticle precursor and at least one second solvent for the reactive moiety, wherein the second solvent phase separates when it is mixed with the first solvent; and

(c) combining said first and second mixtures in the presence of a surface stabilizing agent, wherein upon combination the first and second mixtures phase-separate and nanoparticles are formed.

(d) formulating the nanoparticles into an ink or paste.

(e) forming a film with the ink or paste on a silicon substrate.

2 . The method according to claim 1 , wherein the first solvent comprises an organic solvent, and the second solvent comprises water.

3 . The method according to claim 1 , wherein the first solvent comprises a hydrocarbon solvent, and the second solvent comprises water.

4 . The method according to claim 1 , wherein the nanoparticles comprise silver.

5 . The method according to claim 1 , wherein the reactive moiety comprises a reducing agent.

6 . The method according to claim 1 , wherein the second additive nanoparticles reduce the contact electrical resistance between the semiconductor material and the first conductive nanoparticles after the step (e).

7 . The method according to claim 1 , wherein the reactive moiety comprises a hydroxyl producing agent.

8 . The method according to claim 1 , wherein the surface stabilizing agent, the first solvent, and the second solvent, are adapted so that when the first and second solvents phase separate and form an interface, the surface stabilizing agent migrates to the interface.

9 . The method according to claim 1 , wherein the surface stabilizing agent comprises at least one alkylene group and a nitrogen atom or an oxygen atom.

10 . The method according to claim 1 , wherein the surface stabilizing agent comprises at least substituted amine or substituted carboxylic acid, wherein the substituted group comprise two to thirty carbon atoms.

11 . The method according to claim 1 , wherein the surface stabilizing agent comprises an amino compound, a carboxylic acid compound, or a thiol compound.

12 . The method according to claim 1 , wherein the surface stabilizing agent comprises an amino compound, or a carboxylic acid compound.

13 . The method according to claim 1 , wherein the first mixture comprises the surface stabilizing agent.

14 . The method according to claim 1 , wherein the first mixture comprises the surface stabilizing agent, and the second mixture is free of surface stabilizing agent.

15 . The method according to claim 1 , wherein the phase-separation produces an interface and the nanoparticles form at the interface.

16 . The method according to claim 1 , further comprising the step of collecting the nanoparticles, wherein the collected nanoparticles have an average particle size of about 1 nm to about 20 nm.

17 . The method according to claim 1 , further comprising the step of collecting the nanoparticles, wherein the collected nanoparticles have an average particle size of about 2 nm to about 10 nm, and the nanoparticles have a monodispersity showing standard deviation of 3 nm or less.

18 . The method according to claim 1 , wherein the nanoparticles can be formed into a film having electrical conductivity due to the material in the nanoparticles, or wherein the nanoparticles can be formed into a semiconductive film having semiconductivity due to the material in the nanoparticles, or wherein the nanoparticles can be formed into an electroluminescent film having electroluminescence due to the material in the nanoparticles.

19 . The method according to claim 1 , wherein the volume of the first mixture is greater than the volume of the second mixture.

20 . The method according to claim 1 , wherein the combination is carried out without external application of heat or cooling.

21 . A device, comprising:

an ink or paste disposed on a semiconductor material;

wherein the ink or paste comprises first conductive nanoparticles and further comprises second additive nanoparticles different from the first nanoparticles.

22 . The device according to claim 21 , wherein the first conductive nanoparticles that are fabricated by the method according to steps (a) to (d) in claim 1 .

23 . The device according to claim 21 , wherein the second additive nanoparticles are fabricated according to steps (a) to (d) in claim 1 .

24 . The device according to claim 21 , wherein the conductive and additive particles are inorganic.

25 . The device according to claim 21 , wherein the conductive nanoparticles are silver.

26 . The device according to claim 21 , where the conductive nanoparticle particle size is less than about 1 micron.

27 . The device according to claim 21 , where the conductive nanoparticle particle size is about 1 nm to about 100 nm.

28 . The device according to claim 21 , where the conductive nanoparticle particle size is about 1 nm to about 20 nm.

29 . The device according to claim 21 , where the additive nanoparticles are palladium.

30 . The device according to claim 21 , where the additive nanoparticle particle size is less than 1 micron.

31 . The device according to claim 21 , wherein the material is single crystalline silicon.

32 . The device according to claim 21 , wherein the material is multi-crystalline silicon.

33 . The device according to claim 21 , wherein the material is nano-crystalline silicon.

34 . The device according to claim 21 , wherein the material is amorphous silicon.

35 . The device according to claim 21 , wherein the first and second nanoparticles are processed by inkjet printing.

36 . The device according to claim 21 , wherein the first and second nanoparticles are processed by gravure printing.

37 . The device according to claim 21 , wherein the first and second nanoparticles are processed by flexographic printing.

38 . The device according to claim 21 , wherein the first and second nanoparticles are processed by screen printing.

39 . The device according to claim 21 , wherein the first and second nanoparticles are processed at a temperature less than about 500° C.

40 . The device according to claim 21 , wherein the first and second nanoparticles are processed at a temperature less than about 300° C.

41 . The device according to claim 21 , wherein the first nanoparticles are silver, gold, or copper nanoparticles, or combinations thereof.

42 . The device according to claim 21 , wherein the second nanoparticles are palladium, nickel, titanium, or aluminum nanoparticles, or combinations thereof.

43 . The device according to claim 21 , is a photovoltaic device.

44 . The device according to claim 21 , wherein the first conductive nanoparticles are more electrically conductive than the second additive nanoparticles.

45 . A device, comprising:

at least two inks or pastes disposed on a semiconductor material;

wherein the first ink or paste comprises first conductive nanoparticles, and the second ink or paste comprises second nanoparticles different from the first nanoparticles; and

wherein the second nanoparticles are disposed between the semiconductor material and the first conductive nanoparticles.

46 . The device according to claim 45 , wherein the first conductive nanoparticles are more electrically conductive than the second nanoparticles.

47 . The device according to claim 45 , wherein the second nanoparticles reduce the contact electrical resistance between the semiconductor material and the first conductive nanoparticles.

48 . The device according to claim 45 , wherein the first nanoparticles are silver, gold, or copper nanoparticles, or combinations thereof.

49 . The device according to claim 45 , wherein the second nanoparticles are palladium, nickel, titanium, or aluminum nanoparticles, or combinations thereof.

50 . The device according to claim 45 , wherein the semiconductor material comprises silicon.

51 . The device according to claim 45 , wherein the device is annealed.

52 . The device according to claim 45 , wherein the device is not yet annealed.