Eur. Phys. J. B (2013) 86: 47
https://doi.org/10.1140/epjb/e2012-30614-0

Regular Article

Effect of exciton-spin-orbit-photon interaction in the performance of organic solar cells^*

¹ Centre for Renewable Energy and Low Emissions Technology, Research Institute of the Environment and Livelihoods, Charles Darwin University, 0909 Darwin NT, Australia
² School of Engineering and IT, Charles Darwin University, 0909 Darwin NT, Australia

^a e-mail: MONISHKARITA.NARAYAN@cdu.edu.au

Received: 16 July 2012
Received in final form: 11 October 2012
Published online: 11 February 2013

Abstract

Photon absorptions leading to singlet and triplet excitonic states in organic solar cells are presented in this study. Applying Fermi’s golden rule, the rates of absorption of singlet and triplet excitons are derived using singlet exciton-photon and triplet exciton-spin-orbit-photon-interaction, respectively, as perturbation operators. The rate of triplet absorption depends on the square of the atomic number and hence heavier atoms play the dominant role. Incorporation of heavy metal atoms in the donor organic material enhances the absorption rate and hence absorption, leading of higher generation of excited charge carriers. This increases the conversion efficiency of organic solar cells. The results are compared with experimental studies.