Enhanced Charge Injection Properties of Organic Field Effect Transistor via Molecular Implantation Doping

Organic semiconductors (OSCs) have been widely studied due to their merits such as mechanical flexibility, solution processability, and large-area fabrication. However, because of the Schottky contact at the metal/OSC interfaces, a non-ideal transfer curve feature often appears in the low drain voltage region. Here, we demonstrated a selective contact doping of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F₄-TCNQ) by solid-state diffusion in poly 2,5-bis(3-hexadecylthiophen-2-yl) thieno [3,2-b] thiophene (PBTTT) to enhance carrier injection in bottom-gate PBTTT organic field effect transistors (OFETs). This doping exhibited a high conductivity with favorable charge transport properties [1]. Furthermore, we investigated the effect of post-doping treatment on diffusion of F₄-TCNQ molecules in order to improve the device stability. In addition, the application of the doping technique to the low-voltage operation of PBTTT OFETs with high-k gate dielectrics demonstrated a potential for designing scalable and low-power organic electronic devices by utilizing doping of conjugated polymers.

References
[1] K. Kang et al., Nat. Mater., 15, 896 (2016).