ION MODULATED ORGANIC TRANSISTORS - Doria

Nikolai Kaihovirta2. EXPERIMENTALwas dissolved in ethylacetate and spin-coated onto the P3HTsemiconductor.(a)(b)CH 3OOnnCH 3OH(c)(d)CF 2 CF 2CF 2 CFCFnCH CF 2CH 2m2mO CFCF 2 CF 3H 2 CCHnO ooCF 2F 2 CSO 3 HSO 3 HChart 2.4. The chemical structures for (a) PMMA, (b) PVP, (c) PTFE:PFSA and(c) PVDF:PSSA.The electrolyte “insulators”, which were described in Section 1.2.3, arethe central focus in this thesis. The ones used in this thesis arehygroscopic, that is, they require moisture to some extent for sufficientionic drift. For the HIFETs in Paper 1, a hygroscopic poly(vinyl phenol)(PVP) was used (Chart 2.4 (b)). PVP is also a well-known polymericdielectric insulator. In particular, by cross-linking the PVP the insulatingproperties are excellent [11, 18-20]. By exposing the non-crosslinked PVPto small protic solvents the PVP becomes proton conducting. The effect isutilized for operating the HIFETs at 1 V in air [26, 27]. In this thesis, thePVP (DuPont) was dissolved in isopropanol. It was either spin-coated orreverse gravure coated (for the all-printed HIFET) on the P3HT. The drythickness of the PVP-insulator was between 1.0 - 1.5 µm.All membranes in Papers 2, 3, 4, and 5 have a thickness between 50 -150 µm. The two ion-conducting membranes that have received mostattention in this thesis are tetrafluoroethylene-perfluoro-3,6-dioxa-4-methyl-7-octenesulfonic acid copolymer (PTFE:PFSA) andpoly(vinylidene) poly(styrene sulfonic acid) (PVDF:PSSA) (Charts 2.4 (c)and (d)). PTFE:PFSA (trade name Nafion 115 (DuPont)) is a commercially17