# Magnetic field enhancement of organic photovoltaic cells performance

## TL;DR

This paper demonstrates that applying a magnetic field to organic photovoltaic cells enhances charge separation efficiency by increasing triplet charge transfer states, leading to improved power output.

## Contribution

It introduces a donor-acceptor model showing how magnetic fields modulate charge transfer states, boosting photovoltaic performance.

## Key findings

- Magnetic fields increase triplet charge transfer states.
- Enhanced triplet states reduce recombination losses.
- Power output of the cell is improved with magnetic field application.

## Abstract

Charge separation is a critical process for achieving high efficiencies in organic photovoltaic cells. The initial tightly bound excitonic electron-hole pair has to dissociate fast enough in order to avoid photocurrent generation and thus power conversion efficiency loss via geminate recombination. Such process takes place assisted by transitional states that lie between the initial exciton and the free charge state. Due to spin conservation rules these intermediate charge transfer states typically have singlet character. Here we propose a donor-acceptor model for a generic organic photovoltaic cell in which the process of charge separation is modulated by a magnetic field which tunes the energy levels. The impact of a magnetic field is to intensify the generation of charge transfer states with triplet character via inter-system crossing. As the ground state of the system has singlet character, triplet states are recombination-protected, thus leading to a higher probability of successful charge separation. Using the open quantum systems formalism we demonstrate that not only the population of triplet charge transfer states grows in the presence of a magnetic field, but also how the power outcome of an organic photovoltaic cell is in that way increased.