Time-Resolved Electric Force Microscopy of Charge Trapping in Polycrystalline Pentacene

Abstract

Here we introduce time-resolved electric force microscopy measurements to directly and locally probe the kinetics of charge trap formation in a polycrystalline pentacene thin-film transistor. We find that the trapping rate depends strongly on the initial concentration of free holes and that trapped charge is highly localized. The observed dependence of trapping rate on the hole chemical potential suggests that the trapping process should not be viewed as a filling of midgap energy levels, but instead as a process in which the very creation of trapped states requires the presence of free holes.

Kinetics of occupancy of defect states in poly(3-hexylthiophene):fullerene solar cells

“…Shallow traps centered at 50 and 105 meV were previously indentified using thermally-stimulated current techniques on polymer (P3HT) diodes [16]. Activation energies within the range [31], or slow localization dynamics of electrons on ice surfaces [32]. Therefore molecular and lattice distortions in presence of a charge carrier would lie behind the observed retardation effects.…”

Observation of Unusual Homoepitaxy in Ultrathin Pentacene Films and Correlation with Surface Electrostatic Potential

“…1A) vapor deposited onto amorphous SiO 2 substrates. The pentacene/SiO 2 system is a model crystalline organic semiconductor/insulator interface that is widely studied [25][26][27][28] and used in OFETs, [8][9][10][11] and thus insights into the structure and properties of this interface have the potential to impact understanding of OFET operation. Furthermore, we believe that findings on this model interface can generally be taken as a qualitative guide for the types of issues that are at play in other crystalline organic semiconductor/insulator systems.…”

Light-assisted deep-trapping of holes in conjugated polymers

“…nanoparticle ͉ single molecule spectroscopy ͉ charge injection T he nature of positive charge carriers (holes) in organic conjugated polymers remains obscure despite decades of materials and device research (1)(2)(3)(4)(5)(6)(7)(8)(9). Evidence suggests that there are at least two main types of holes, namely shallowly trapped (mobile) holes and deeply trapped holes (DTHs) (10)(11)(12).…”