Clevios™ M V2 (3,4-ethylene dioxythiophene);
Clevios™ C-B 40 V2 (Fe(III)tosylate in butanol)*;
* Clevios C-B 40 V2 can be replaced with a mixture of 75 weight% Clevios C-B 54 V3 and 25 weight % butanol
Clevios™ P (PEDOT:PSS) or Polyepoxysilane
Deposition of an adhesion layer on glass substrates:
An adhesion layer of 10-20 nm is necessary, especially for deposition on glass. Without the adhesion layer the In-Situ-PEDOT layers may peel off during the washing step. Clevios™ P or a Polyepoxysilane can be recommended as an adhesion layer.
Clevios™ P as an adhesion layer
Clevios™ P AI4083 or CH8000 is spin-coated as a 10-20nm film onto a glass substrate and subsequently baked at 200° C for ca. 10 min on a hot plate.
Polyepoxysilane as an adhesion layer
Polyepoxysilane (e.g. Silquest® A187, Momentive) is spin-coated onto a glass substrate (1000rpm, t=120sec, Acc.2, lid closed) or simply dipped in diluted epoxysilane solution (e.g. 0.1% Silquest® A187 in Isopropanol) and then dried at 50°C for 5min in air. Humidity has an impact on the cross-linking of the epoxysilane. Medium humidity of 30-70% is our preference.
Mixing the solution:
The three components: Clevios™ M V2, Clevios™ CB 40 V2, and Imidazole are mixed in a weight-ratio of 1 : 25 : 0.5. In a first step Imidazole is dissolved in CB 40. Then Clevios™ M V2 is added. The mixture can be filtered by using a syringe (0.45µm PDVF). Density: Clevios™ M V2: 1,33g/ccm, Clevios™ CB 40 V2: 1,03g/ccm.
Coating the solution:
The solution has to be processed immediately after the addition of Clevios™ M V2. After 5-10 min the solution starts to gel due to polymerization and the films will be inhomogeneous. The solution can be spin-coated at spin speeds of 200-3000rpm and thin homogeneous films are formed. On a 50mm x 50mm substrate the film thickness is 170nm at 1000rpm, t=30 sec , Acc. 2, lid closed
Drying the film
1. Step: 5 min at 50°C on hot plate in air
2. Step: 60 min at room temperature in air
The film will change colour as EDOT polymerises while drying.
The films are washed by shaking the substrate in a beaker filled with deionised water thoroughly to remove the Fe-salts. Adhering water is blown off in a N2 flow.
The conductivity can be determined by painting two parallel conducting bars (silver paste) on top of the film and by measuring the impedance with an Ohm meter. The conductivity is defined as the reciprocal of the product of sheet resistance and layer thickness. For in-situ-PEDOT films 400-600 S/cm can be achieved.