Solution-processable tungsten oxide buffer layers and electronics comprising same

1. A composition in the form of a suspension, said composition containing

(a) tungsten oxide nanoparticles selected from the group consisting of

nanoparticles of pure tungsten oxide,

nanoparticles of doped tungsten oxide, and

core-shell nanoparticles, whereby the shell is composed of tungsten oxide or doped tungsten oxide and the core is composed of a different inorganic material;

(b) a homogeneous solvent composition comprising

water,

a first organic solvent forming a binary azeotrope with water;

whereby the amount of water in said solvent composition (b) is below the total azeotropic water content with respect to said first organic solvent;

whereby the ratio amount of nanoparticles: amount of water is below 9:1 (w/w), and the amount of water in the composition is in the range of 0.1-20 wt %; and

wherein the composition is free of surfactants and dispersing agents.

2. The composition of claim 1 , wherein said homogeneous solvent composition (b) additionally comprises a second organic solvent forming a binary azeotrope with water,

whereby the amount of water in said solvent composition (b) is below the total azeotropic water content with respect to said first and said second organic solvent.

3. The composition of claim 1 , wherein said homogeneous solvent composition (b) additionally comprises a third organic solvent not forming a binary azeotrope with water.

4. The composition of claim 1 , consisting of

(a)

Water

1 st organic solvent

wt %

wt %

wt %

0.2-4 

0.2-4 

92-99.6 ethanol

or

0.2-10

0.2-10

80-99.6 2-propanol

or

0.2-20

0.2-20

60-99.6 1-propanol

or

0.2-16

0.2-16

68-99.6 1-butanol

or

0.2-20

0.2-20

60-99.6 2-butanol

or

0.2-10

0.2-10

80-99.6 tert-butanol

or

0.2-13

0.2-13

74-99.6 acetonitrile

or

0.2-4 

0.2-4 

92-99.6 propionitrile

.

5. The composition of claim 1 , wherein

said first organic solvent is selected from the group consisting of alcohols and nitriles;

said second organic solvent is selected from the group consisting of alcohols, nitriles, ketones, esters, ethers, aldehydes and alkoxy-alcohols;

said third organic solvent is selected from the group consisting of alcohols, nitriles, ketones, esters, ethers, aldehydes and alkoxy-alcohols;

and whereby said alcohols may be partly or fully substituted with halogen,

and whereby said alcohols may contain multiple bonds,

and whereby said organic solvents may include linear, branched or cyclic derivatives.

6. The composition of claim 1 , wherein the amount of nanoparticles is in the range of 0.1-20 wt % and the amount of homogeneous solvent composition is in the range of 80-99.9 wt %.

7. A method for manufacturing the composition according to claim 1 , comprising the steps of

(a) providing the homogeneous solvent composition;

(b) providing nanoparticles;

(c) combining said nanoparticles with said homogeneous solvent composition to obtain the suspension.

8. The composition of claim 2 , consisting of:

2-10 wt % of the tungsten oxide nanoparticles (a);

2-10 wt % water; and

0.6-80 wt % 1-propanol/0.5-99 wt% methanol as 1 st /2 nd organic solvent.