Optical-cavity manipulation strategies of singlet fission systems mediated by conical intersections: insights from fully quantum simulations

TL;DR

This paper presents a theoretical study on manipulating singlet fission in polaritonic systems via conical intersections, using quantum simulations to explore mechanisms for enhancing photovoltaic efficiency.

Contribution

It introduces a fully quantum simulation approach to understand and control singlet fission through polaritonic conical intersections, highlighting new mechanisms for efficiency improvement.

Findings

Cavity effects can enhance or suppress singlet fission.

Population can be localized on the singlet state through cavity engineering.

Polaritonic conical intersections significantly influence singlet fission dynamics.

Abstract

We offer a theoretical perspective on simulation and engineering of polaritonic conical-intersection-driven singlet-fission (SF) materials. We begin by examining fundamental models, including Tavis-Cummings and Holstein-Tavis-Cummings Hamiltonians, exploring how disorder, non-Hermitian effects, and finite temperature conditions impact their dynamics, setting the stage for studying conical intersections and their crucial role in SF. Using rubrene as an example and applying the numerically accurate Davydov-Ansatz methodology, we derive dynamic and spectroscopic responses of the system and demonstrate key mechanisms capable of SF manipulation, viz. cavity-induced enhancement/weakening/suppression of SF, population localization on the singlet state via engineering of the cavity-mode excitation, polaron/polariton decoupling, collective enhancement of SF. We outline unsolved problems and challenges in the field, and share our views on the development of the future lines of research. We emphasize the significance of careful modeling of cascades of polaritonic conical intersections in high excitation manifolds and envisage that collective geometric phase effects may remarkably affect the SF dynamics and yield. We argue that microscopic interpretation of the main regulatory mechanisms of polaritonic conical-intersection-driven SF can substantially deepen our understanding of this process, thereby providing novel ideas and solutions for improving conversion efficiency in photovoltaics.