Enhancing ion doping and charge transport in polymer electrochemical transistors through poly(3-hexylthiophene) nanowire integration

Abstract

The balance between ion implantation and carrier transport is a critical factor in achieving high-performance polymer electrochemical transistors (PECTs). While the crystallinity of polymer films typically enhances the charge transport capacity of these devices, the orderly packed chains impede the injection of ions. In this study, poly(3-hexylthiophene) (P3HT) nanowires were incorporated into PECTs to address this issue. The μC_v value (μ: charge mobility, C_v: volumetric capacitance; the product μC_v has been proposed as a figure of merit for OECT materials) of the films with embedded nanowires (WN) is approximately three times that of the films without nanowires (W/O N), and the subthreshold swing of the WN devices is also lower than that of the W/O N devices. These findings indicate the superior ion doping property of the WN devices. The time evolution of the absorption difference spectra for the films demonstrates that the ions preferentially dope the J-aggregate regions in the WN films, which correspond to the nanowires. The results suggest that the nanowires enhance ion doping in the WN films, likely due to their large specific surface area. This work demonstrates a feasible strategy to effectively improving ion implantation while maintaining charge mobility by introducing polymer crystallization into PECT devices.