Minimal model for charge transfer excitons at the dielectric interface

TL;DR

This paper develops a minimal theoretical model to describe charge transfer excitons at dielectric interfaces, emphasizing the roles of hole mass and localization in organic solar cells.

Contribution

It introduces a new minimal model for CT excitons that accounts for inhomogeneous dielectric effects and broken inversion symmetry.

Findings

Both a light hole mass and hole localization are essential for CT exciton formation.

The model accurately captures the wavefunction of CT excitons at dielectric interfaces.

Highlights the importance of dielectric inhomogeneity in exciton behavior.

Abstract

Theoretical description of the charge transfer (CT) exciton across the donor-acceptor interface without the use of a completely localized hole (or electron) is a challenge in the field of organic solar cells. We calculate the total wavefunction of the CT exciton by solving an effective two-particle Schrodinger equation for the inhomogeneous dielectric interface. We formulate the magnitude of the CT and construct a minimal model of the CT exciton under the breakdown of inversion symmetry. We demonstrate that both a light hole mass and a hole localization along the normal to the dielectric interface are crucial to yield the CT exciton.