Trapping time statistics and efficiency of transport of optical excitations in dendrimers

TL;DR

This paper provides a theoretical analysis of excitation energy transport in dendrimers, deriving exact expressions for trapping time distribution and efficiency, considering decay processes and energy biases, to understand how structural parameters influence transport performance.

Contribution

It introduces exact analytical expressions for trapping time and efficiency in dendrimers, accounting for decay and energy bias effects, advancing understanding of energy transport mechanisms.

Findings

Trapping efficiency depends mainly on the product of decay rate and mean first passage time.

Derived exact Laplace transforms for trapping time distribution.

Transport efficiency varies with dendrimer generations and energy bias.

Abstract

We theoretically study the trapping time distribution and the efficiency of the excitation energy transport in dendritic systems. Trapping of excitations, created at the periphery of the dendrimer, on a trap located at its core, is used as a probe of the efficiency of the energy transport across the dendrimer. The transport process is treated as incoherent hopping of excitations between nearest-neighbor dendrimer units and is described using a rate equation. We account for radiative and non-radiative decay of the excitations while diffusing across the dendrimer. We derive exact expressions for the Laplace transform of the trapping time distribution and the efficiency of trapping and analyze those for various realizations of the energy bias, number of dendrimer generations, and relative rates for decay and hopping. We show that the essential parameter that governs the trapping efficiency, is the product of the on-site excitation decay rate and the trapping time (mean first passage time) in the absence of decay.