Coherent Electron Transport in Air‐Stable, Printed Single‐Crystal Organic Semiconductor and Application to Megahertz Transistors

Organic semiconductors (OSCs) have attracted growing attention for optoelectronic applications such as field‐effect transistors (FETs), and coherent (or band‐like) carrier transport properties in OSC single crystals (SCs) have been of interest as they can lead to high carrier mobilities. Recently, such p‐type OSC SCs compatible with a printing technology have been used to achieve high‐speed FETs; therefore, developments of n‐type counterparts may be promising for realizing high‐speed complementary organic circuits. Herein, coherent electron transport properties in a printed SC of a state‐of‐the‐art, air‐stable n‐type OSC, PhC2−BQQDI, by means of variable‐temperature gated Hall effect measurements and X‐ray single‐crystal diffraction analyses in conjunction with band structure calculations, are reported. Furthermore, the SC FET is tested for high‐speed operations, which obtains a cutoff frequency of 4.3 MHz at an operation voltage of 20 V in air. Thus, PhC2−BQQDI is shown as a new candidate for practical applications of SC‐based, organic complementary devices. A state‐of‐the‐art n‐type organic semiconductor, PhC2−BQQDI, which can be used to form single‐crystalline thin films by printing, is identified as a band‐transport material by means of variable‐temperature gated Hall effect measurements. The printed PhC2−BQQDI single crystal is also used to demonstrate a high‐frequency transistor with a capability of 4.3 MHz under ambient atmosphere.