## 4 Summary  
In this work, we demonstrated a fully photopatternable PEDOT:Tos OECT showing excellent bias stress stability, and we adopted a scan-rate-dependent measurement scheme to illustrate the kinetic and non-kinetic hysteresis. A strong enhancement of both could be revealed by thermal annealing, and we utilized impedance analysis to explain the changes in the two hysteresis regimes upon annealing. PEDOT:Tos was presumably well-mixed for non-annealed samples (all states were equivalent and had no dopant-rich or -poor domains), showing Faradaic behavior. Annealing fostered further polymerization of PEDOT, which might cause the demixing of PEDOT and Tos [23], showing a non-Faradaic behavior. Similar to PEDOT:PSS, ions might become trapped (represented by a CPE), causing an increased capacitance [27].  
This work illustrated that PEDOT:Tos films employing solid electrolytes could be viable for applications where reliable long operation cycles are desired. A VGS scan-rate-dependent measurement scheme captured the effects of the changing material properties on the device performances. This work further illustrated a simple process modification in thermal annealing to achieve varying hysteresis levels without changing the starting material, suitable for neuromorphic applications utilizing hysteresis [13; 14]. While this work clearly distinguished between the non-kinetic and kinetic regimes of hysteresis, the true origin of the non-kinetic hysteresis remains open for investigation. In particular, further studies on micro- and nano-scale changes in PEDOT:Tos films upon annealing will  
Figure 4: Impedance measurements of OECTs employing PEDOT:Tos films annealed for \(0,1,4\,\mathrm{h}\). The corresponding fitting circuits and parameters are given as insets. The non-annealed device shows mostly a Faradaic response, which changes to non-Faradaic responses after annealing. The phase also indicates that the capacitances rapidly increase upon annealing. Here, \(W,L,g=$150\,\mathrm{\SIUnitSymbolMicro m}$,$150\,\mathrm{\SIUnitSymbolMicro m}$\); the thicknesses are \(103,119,141\,\mathrm{nm}\) for thermal annealing of \(0,1,4\,\mathrm{h}\), respectively **(a–c)**. The measurements were taken in potentiostatic mode with the source and drain shorted, with an RMS amplitude of \(10\,\mathrm{mV}\) and without any DC offset. The instabilities around the \(50\,\mathrm{Hz}\) range probably originate due to the non-standard cables connecting the measurement setup inside the glovebox to the standard Autolab cables situated outside the glovebox.  
provide valuable insights. If deep defects indeed cause the observed changes in hysteresis, annealing could pave the way to quantify and assess the effect of defect states on the OECTs' properties.  
**Author Contributions:** R.S.: conceptualization, methodology, investigation, formal analysis, data curation, visualization, writing--original draft preparation. L.M.B.: methodology, formal analysis, software, writing--review and editing, supervision. A.W.: formal analysis, writing--review and editing, supervision. H.K.: project administration, resources, writing--review and editing, supervision. K.L.: validation, writing--review and editing, supervision. All authors have read and agreed to the published version of the manuscript.  
**Funding:** [PERSON] and [PERSON] are grateful for funding from the German Research Foundation (DFG) under the grant KL 2961/5-1. The authors also thank the Bundesministerium fur Bildung und Forschung (BMBF) for funding from the project BAYOEN (01 IS21089) and EC/SAB for funding in the ESF-Project \"Re-Learning\" (Funding No. 100382146).  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** All data related to this article are available upon request.  
**Conflicts of Interest:** The authors declare no conflict of interest.