Semiclassical Model for Calculating Exciton and Polaron Pair Energetics at Interfaces

TL;DR

This paper introduces an enhanced semiclassical model that integrates ab initio calculations to more accurately predict exciton and polaron pair energetics at interfaces, aiding photovoltaic device optimization.

Contribution

It combines classical dielectric interface models with ab initio data to improve predictions of exciton and polaron binding energies at interfaces.

Findings

Molecular dipole insertion can enhance polaron pair dissociation.

Sharp dielectric transitions significantly influence polaron dissociation.

The model successfully predicts behaviors at organic and hybrid interfaces.

Abstract

Exciton and polaron pair dissociation is a key functional aspect of photovoltaic devices. To improve upon the current state of interfacial transport models, we augment the existing classical models of dielectric interfaces by incorporating results from ab initio calculations, allowing us to calculate exciton and polaron binding energies more accurately. We demonstrate the predictive capabilities of this new model using two interfaces: (i) the boron subphthalocyanine chloride (SubPc) and C60 interface, which is an archetype for many organic photovoltaic devices; and (ii) pentacene and silicon (100), which represents a hybrid between organic and inorganic semiconductors. Our calculations predict that the insertion of molecular dipoles at interfaces can be used for improving polaron pair dissociation and that sharp transitions in dielectric permittivity can have a stronger effect on the polaron pair dissociation than even the electron-hole Coulomb interaction.