Switching of Electron and Ion Conductions by Reversible H2O Sorption in n-Type Organic Semiconductors

Polar H2O molecules generally act as trapping sites and suppress the electron mobility of n-type organic semiconductors, making chemical design of H2O-tolerant and responsive n-type semiconductors an important step toward multifunctional electron-ion coupling devices. The introduction of effective electrostatic interactions between potassium ions (K+) and carboxylate (-COO-) anions into the electron-transporting naphthalenediimide pi-framework enables the design of high-performance H2O-tolerant n-type semiconductors with a reversible H2O adsorption-desorption ability, where the electron mobility and K+ ionic conductivity were coupled with the reversible H2O sorption behavior. The reversible H2O adsorption into the crystals enhanced the electron mobility from 0.04 to 0.28 cm(2) V-1 s(-1), whereas the K+ ionic conductivity decreased from 3.4 x 10(-5) to 4.7 x 10(-7) S cm(-1). Because this reversible electron-ion conducting switch is responsive to H2O sorption behavior, it is a strong candidate for H2O gating carrier transport systems.