Coupled exciton model with off-diagonal disorder for optical excitations in extended dendrimers

TL;DR

This paper introduces a coupled exciton model with off-diagonal disorder to analyze optical excitations in extended dendrimers, revealing their potential as artificial fractal antennas for light energy capture.

Contribution

It develops a phenomenological exciton model incorporating Gaussian-distributed hopping integrals and demonstrates exciton funnel effects in dendrimers.

Findings

Optical excitation energy decreases with dendrimer size.

Dendrimers act as artificial fractal antenna systems.

Exciton funnels facilitate energy capture.

Abstract

A phenomenological coupled exciton model is proposed in order to characterize optical excitations in extended dendrimers. An onsite exciton state is assigned at each phenyl rings and a nearest neighbor hopping integral which obeys the Gaussian distribution is considered between the exciton states. The decreasing optical excitation energy with respect to the dendrimer size indicates the presence of exciton funnels along the backbone of the dendrimers. Therefore, the extended dendrimers can work as artificial fractal antenna systems which capture energy of light.