Enhancing stability of doped semiconductor polymers with cytop protective layers: An examination of electrical property retention

Doping is a critical method for enhancing the electrical properties of semiconducting polymers, with ongoing innovations in dopant molecules and doping techniques. However, introducing dopants can disrupt the conjugated backbone of polymers like poly[(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene)] (PBTTT) and indendithiophene-benzothiadiazole (IDTBT), accelerating the degradation of electronic properties, particularly under air exposure. Cytop, as a cross-linked fluorine-rich polymer material, can form amorphous, smooth hydrophobic surfaces that are isolated from air. However, there is a lack of research on Cytop to inhibit the degradation of electrical properties of polymers in air. This study employed ion-exchange and immersion doping techniques on these polymers and explored the protective effects of the crosslinked polymer Cytop as a barrier layer. We measured the electrical properties of doped films both with and without the Cytop layer under various conditions to determine its impact on the polymers' stability. The findings demonstrate that Cytop significantly enhances the films' stability, offering insights into the long-term performance and reliability of doped semiconducting polymers.