# Correlated electron-hole mechanism for molecular doping in organic semiconductors

## TL;DR

This study combines advanced ab initio methods and model Hamiltonians to elucidate the electron-hole interactions and charge transfer mechanisms in doped organic semiconductors, explaining room-temperature doping and challenging traditional impurity level classifications.

## Contribution

It introduces a comprehensive approach that accounts for electron-hole interactions and environmental effects, providing new insights into molecular doping in organic semiconductors.

## Key findings

- Electron-hole interactions stabilize charge transfer states.
- Room-temperature dopant ionization is possible despite deep acceptor levels.
- Partial and full charge transfer scenarios are reconciled with experimental data.

## Abstract

The electronic and optical properties of the paradigmatic F4TCNQ-doped pentacene in the low-doping limit are investigated by a combination of state-of-the-art many-body \emph{ab initio} methods accounting for environmental screening effects, and a carefully parametrized model Hamiltonian. We demonstrate that while the acceptor level lies very deep in the gap, the inclusion of electron-hole interactions strongly stabilizes dopant-semiconductor charge transfer states and, together with spin statistics and structural relaxation effects, rationalize the possibility for room-temperature dopant ionization. Our findings reconcile available experimental data, shedding light on the partial vs. full charge transfer scenario discussed in the literature, and question the relevance of the standard classification in shallow or deep impurity levels prevailing for inorganic semiconductors.