Electronic Transport Properties of Pentacene Single Crystals upon Exposure to Air

TL;DR

This study investigates how exposure to air affects the electronic transport in pentacene single crystals, revealing reversible oxygen doping effects and water-induced charge trapping, with implications for organic electronic device stability.

Contribution

It demonstrates the reversible diffusion of air components in pentacene crystals and identifies two competing mechanisms influencing electronic transport.

Findings

Oxygen increases hole conduction in pentacene.

Water creates charge trapping sites within the crystal.

Oxygen effects are enhanced by visible light.

Abstract

We report the effect of air exposure on the electronic properties of pentacene single crystals. Air can diffuse reversibly in and out of the crystals and controls the physical properties. We discern two competing mechanisms that modulate the electronic transport. The presence of oxygen increases the hole conduction, as in dark four O2 molecules introduce one charge carrier. This effect is enhanced by the presence of visible light. Contrarily, water, present in ambient air, is incorporated in the crystal lattice and forms trapping sites for injected charges.