Organic field-effect transistor comprising a dielectric layer exhibiting high dielectric permittivity and being stable with temperature
The invention relates to a composition comprising a blend of fluorinated electroactive polymers and having a dielectric permittivity that exhibits greater stability over the operating temperature range with respect to each polymer employed on its own. The invention also relates to formulations and films produced on the basis of said composition. The invention also relates to a field-effect transistor, at least part of the dielectric layer of which is composed of a blend of fluorinated electroactive polymers.
1. A composition comprising a blend of fluorinated electroactive polymers, said blend being composed of:
a) at least one fluorinated terpolymer of formula P(VDF-X-Y) comprising units derived from:
vinylidene fluoride (VDF),
units derived from a monomer X, X being trifluoroethylene (TrFE), and
a third monomer Y chosen from either chlorotrifluoroethylene or 1,1-chlorofluoroethylene, wherein the units derived from the monomer Y contribute from 1 to 15 mol % towards the sum of units of the at least one fluorinated terpolymer; and
b) at least one copolymer of formula P(VDF-TrFE) comprising units derived from vinylidene fluoride and units derived from trifluoroethylene, the proportion of units derived from trifluoroethylene being greater than 50 mol % relative to the sum of the units derived from vinylidene fluoride and trifluoroethylene.
2. The composition as claimed in claim 1 , wherein the units derived from the monomer Y contribute from 1 to 12 mol % towards the sum of units of the at least one fluorinated terpolymer.
3. The composition as claimed in claim 1 , wherein the proportion by weight of component b) is between 10 wt % and 50 wt % of the total weight of the composition.
4. The composition as claimed in claim 1 , wherein the proportion of units derived from trifluoroethylene in the copolymer is greater than 50 mol % relative to the sum of the units derived from vinylidene fluoride and from trifluoroethylene.
5. The composition as claimed in claim 1 , further comprising up to 2% by weight of an additive, said additive being a (meth)acrylic polymer.
6. The composition as claimed in claim 1 , said composition exhibiting a relative permittivity ε r of higher than 30 measured at 1 kHz over a temperature range from 20° C. to 80° C.
7. A formulation based on fluorinated electroactive polymers comprising the composition as claimed in claim 1 in solution in a solvent.
8. The formulation as claimed in claim 7 , wherein said solvent is chosen from dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ketones, furans, esters, carbonates, phosphates, and mixtures thereof.
9. The composition as claimed in claim 1 , wherein the proportion by weight of component b) is between 30 wt % and 50 wt % of the total weight of the composition.
10. The composition as claimed in claim 1 , wherein the proportion by weight of component b) is between 40% and 50% of the total weight of the composition.
11. The composition of claim 1 , wherein the composition is configured to exhibit a relative dielectric permittivity that varies by +/−10 measured at 1 kHz over a temperature range from 0° C. to 100° C.
12. The composition of claim 1 , wherein the composition is configured to exhibit a relative dielectric permittivity that varies by +/−10 measured at 1 kHz over a temperature range from 15° C. to 80° C.
13. The composition of claim 1 , wherein the composition is configured to exhibit a relative dielectric permittivity that varies by +/−5 measured at 1 kHz over a temperature range from 0° C. to 100° C.
14. The composition of claim 1 , wherein the composition is configured to exhibit a relative dielectric permittivity that varies by +/−5 measured at 1 kHz over a temperature range from 15° C. to 80° C.
15. The composition of claim 1 , wherein the composition is configured to substantially not exhibit hysteresis in dielectric permittivity between rising and falling temperatures over a temperature range from 0° C. to 100° C. when dielectric permittivity is measured at 1 kHz.