Predicting the electronic structure of weakly interacting hybrid systems: The example of nanosized pea-pod structures

TL;DR

This paper introduces a simple predictive scheme for the electronic structure of van-der-Waals bound hybrid systems, demonstrated on nano-peapods, highlighting the dominant role of ionization potential and minimal polarization effects.

Contribution

The study presents a novel, straightforward method to predict electronic structures of hybrid systems based solely on subunit properties, validated on nanosized peapod structures.

Findings

Ionization potential of the polymer dominates level alignment

Charge redistribution effects are minimal

Polarization effects are minor due to geometry and dielectric properties

Abstract

We provide a simple scheme for predicting the electronic structure of van-der-Waals bound systems, based on the mere knowledge of the electronic structure of the subunits. We demonstrate this with the example of nano-peapods, consisting of polythiophene encapsulated in single-wall carbon nanotubes. Using density functional theory we disentangle the contributions to the level alignment. The main contribution is shown to be given by the ionization potential of the polymer inside the host, which, in turn is determined by the curvature of the tube. Only a small correction arises from charge redistributions within the domains of the constituents. Polarization effects turn out to be minor due to the cylindrical geometry of the peapods and their dielectric characteristics. Our findings open a perspective towards designing opto-electronic properties of such complex materials.