Energy Transfer Directly to Bilayer Interfaces to Improve Exciton Collection in Organic Photovoltaics

TitleEnergy Transfer Directly to Bilayer Interfaces to Improve Exciton Collection in Organic Photovoltaics
Publication TypeJournal Article
Year of Publication2015
AuthorsEisenmenger ND, Delaney KT, Ganesan V, Fredrickson GH, Chabinyc ML
JournalJournal of Physical Chemistry C
Volume119
Issue33
Start Page19011
Pagination19011–19021
Date Published08/2015
ISSN1932-7447
Keywords21975, ARO, Chabinyc, CNSI/MRL, CSC, Fredrickson, GSR, MRL, NSF-Grad, NSF-SOLAR
Abstract

Ternary blends and energy cascades are gaining popularity as ways to engineer absorption as well as exciton and charge collection in organic solar cells. Here, we use kinetic Monte Carlo simulations to investigate energy cascade designs for improving exciton collection in bilayer solar cells via a Förster energy transfer mechanism. We determine that an interfacial monolayer (C) between the donor and acceptor with a D ? A ? C energy cascade will lead to good exciton collection, allowing for {\textgreater}90{%} collection, even for energy donor layers up to 75 nm thick. We further examine how roughening the interface, increasing the exciton diffusion length, and using other energy cascade designs affect the enhancement from the energy transfer. We also propose using the inherent charge transfer states at the interfaces as energy acceptors and estimate that the Förster radius could be as large as 3.4 nm, leading to nearly 70{%} improvement in exciton collection, without the need for a third material. Ternary blends and energy cascades are gaining popularity as ways to engineer absorption as well as exciton and charge collection in organic solar cells. Here, we use kinetic Monte Carlo simulations to investigate energy cascade designs for improving exciton collection in bilayer solar cells via a Förster energy transfer mechanism. We determine that an interfacial monolayer (C) between the donor and acceptor with a D ? A ? C energy cascade will lead to good exciton collection, allowing for {\textgreater}90{%} collection, even for energy donor layers up to 75 nm thick. We further examine how roughening the interface, increasing the exciton diffusion length, and using other energy cascade designs affect the enhancement from the energy transfer. We also propose using the inherent charge transfer states at the interfaces as energy acceptors and estimate that the Förster radius could be as large as 3.4 nm, leading to nearly 70{%} improvement in exciton collection, without the need for a third material.

URLhttp://dx.doi.org/10.1021/acs.jpcc.5b05749
DOI10.1021/acs.jpcc.5b05749
Grant: 
CSC, MRL (DMR-1121053)