Efficient n-Doping and Hole Blocking in Single-Walled Carbon Nanotube Transistors with 1,2,4,5-Tetrakis(tetramethylguanidino)ben-zene

Abstract

Efficient, stable, and solution-based n-doping of semiconducting single-walled carbon nanotubes (SWCNTs) is highly desired for complementary circuits but remains a significant challenge. Here, we present 1,2,4,5-tetrakis(tetramethylguanidino)benzene (ttmgb) as a strong two-electron donor that enables the fabrication of purely n-type SWCNT field-effect transistors (FETs). We apply ttmgb to networks of monochiral, semiconducting (6,5) SWCNTs that show intrinsic ambipolar behavior in bottom-contact/top-gate FETs and obtain unipolar n-type transport with 3-5-fold enhancement of electron mobilities (approximately 10 cm V s), while completely suppressing hole currents, even at high drain voltages. These n-type FETs show excellent on/off current ratios of up to 10, steep subthreshold swings (80-100 mV/dec), and almost no hysteresis. Their excellent device characteristics stem from the reduction of the work function of the gold electrodes via contact doping, blocking of hole injection by ttmgb on the electrode surface, and removal of residual water from the SWCNT network by ttmgb protonation. The ttmgb-treated SWCNT FETs also display excellent environmental stability under bias stress in ambient conditions. Complementary inverters based on n- and p-doped SWCNT FETs exhibit rail-to-rail operation with high gain and low power dissipation. The simple and stable ttmgb molecule thus serves as an example for the larger class of guanidino-functionalized aromatic compounds as promising electron donors for high-performance thin film electronics.

Printable Semiconductors for Backplane TFTs of Flexible OLED Displays

“…Additionally, CNT transistors generally showed p‐channel transfer characteristics under ambient conditions owing to the adsorption of moisture and oxygen. The doping strategy was demonstrated effectively to convert major carrier types to n‐channel characteristics . However, the encapsulation layer was needed because of the sensitivity of n‐dopants to oxygen and moisture .…”

Conductivity Tuning via Doping with Electron Donating and Withdrawing Molecules in Perovskite CsPbI3 Nanocrystal Films

“…This strategy has been applied widely to polymeric and molecular solids, 2D materials, single‐walled carbon nanotubes (SWCNTs), and semiconductor nanocrystals . For example, molecular doping in SWCNTs has enabled the realization of exceptionally high thermoelectric power factors (both n‐ and p‐type) and the control over field‐effect transistor (FET) polarity for digital logic circuits . Wu et al first applied 2,3,5,6‐tetrafluoro‐7,7,8,8‐tetracyanoquinodimethane (F 4 TCNQ) in methylammonium (MA) lead iodide films and found reduced contact resistance between the thin film and the adjacent conductive substrate .…”

High‐Performance Photoinduced Memory with Ultrafast Charge Transfer Based on MoS2/SWCNTs Network Van Der Waals Heterostructure

“…Then, the photogenerated holes of MoS 2 can simply enter the SWCNTs network under a negative electric field though the high‐quality and trap‐free interface between MoS 2 and SWCNTs network. Finally, because there are stable charge traps in the SWCNTs network, which originates from the water or hydroxyl groups on polar substrate surfaces (such as glass or SiO 2 ), the photogenerated holes are effectively trapped into the charge traps of the SWCNTs network under a negative electric force. This can prevent the recombination of photogenerated electron–hole pairs.…”