Electron traps in polyethylene due to water

Electron traps in polyethylene (PE) origin from water has been calculated using density functional theory. Atomistic structure has been simulated using molecular dynamics (MD) and used to calculate the electronic structure. Densities comparable with experimentally determined values are obtained. Both single water molecules and cluster of water molecules are considered. For a single water molecule both electron and hole states are within the bands from PE. The electron state is close to the conduction band minima (CBM) and may coincide with the CBM depending on the local atomic density. The absence of electron traps due to water is contradictory to previous simulation results but can be explained by atomic density and relaxation of conduction states of PE. Systems with 10 water molecules relaxed to two pentamers in the MD simulations. Calculation of trap levels of the pentamers result in trap levels in the order of 0.1-0.3 eV.