Analytical approach to the magneto-fluorescence of triplet excitons

TL;DR

This paper introduces an analytical framework for modeling the magneto-fluorescence lineshapes of triplet excitons, accounting for molecular orientation averaging, thus enhancing understanding and analysis of magnetic field effects on fluorescence.

Contribution

The authors develop an analytical method to accurately average over molecular orientations in magneto-fluorescence modeling, improving upon previous numerical approaches.

Findings

Provides precise numerical routines for matrix element averaging.

Develops semi-analytical approximations for experimental data modeling.

Enhances analytical understanding of magnetic field effects on triplet exciton fluorescence.

Abstract

The fluorescence of triplet excitons and color-centers is strongly dependent on magnetic field that mixes the zero field spin eigenstates that determine the radiative recombination rates back into the singlet ground state through spin-orbit coupling. For films of molecules, and polycrystalline color-centers samples an average over molecular orientations has to be performed to model the magneto-fluorescence lineshapes. This limits our analytical understanding of the lineshapes and complicates the analysis of the fluorescence dependence on magnetic field. Here, we present a framework that allows to average over triplet molecular orientations analytically. Our approach provides very accurate numerical routines computing precisely the averages matrix elements that appear in magneto-fluorescence and semi-analytical approximations that can be used to model experimental traces.