Practical efficiency limits in organic photovoltaic cells: Functional dependence of fill factor and external quantum efficiency

Jonathan D. Servaites, Mark A. Ratner, Tobin J. Marks

Research output: Contribution to journalArticle

87 Citations (Scopus)

Abstract

We evaluate practical power conversion efficiency limits (lim) in bulk-heterojunction organic photovoltaic (BHJ OPV) cells and how the field dependence of exciton dissociation affects cell efficiencies. We treat the fill factor limit as a function of the donor-acceptor lowest unoccupied molecular orbital offset energy (ELLO), calculating how this limit varies with decreasing ELLO. We also evaluate OPV external quantum efficiency as a function of wavelength from the optical transmittance and internal quantum efficiency limitations. For a given ELLO, we numerically optimize donor bandgap and lim and show that lim >10% should be possible for hypothetical OPV systems generating free charge carriers efficiently at ELLO ∼0.3-0.4 eV. Current BHJ OPVs with low ELLO values appear to be limited to cell efficiencies of ∼5% largely as a consequence of incomplete exciton dissociation.

Original languageEnglish
Article number163302
JournalApplied Physics Letters
Volume95
Issue number16
DOIs
Publication statusPublished - 2009

Fingerprint

photovoltaic cells
quantum efficiency
excitons
dissociation
cells
heterojunctions
charge carriers
transmittance
molecular orbitals
wavelengths
energy

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

@article{8df3e2ca12ad4018acf6eaa0d7b2791d,
title = "Practical efficiency limits in organic photovoltaic cells: Functional dependence of fill factor and external quantum efficiency",
abstract = "We evaluate practical power conversion efficiency limits (lim) in bulk-heterojunction organic photovoltaic (BHJ OPV) cells and how the field dependence of exciton dissociation affects cell efficiencies. We treat the fill factor limit as a function of the donor-acceptor lowest unoccupied molecular orbital offset energy (ELLO), calculating how this limit varies with decreasing ELLO. We also evaluate OPV external quantum efficiency as a function of wavelength from the optical transmittance and internal quantum efficiency limitations. For a given ELLO, we numerically optimize donor bandgap and lim and show that lim >10{\%} should be possible for hypothetical OPV systems generating free charge carriers efficiently at ELLO ∼0.3-0.4 eV. Current BHJ OPVs with low ELLO values appear to be limited to cell efficiencies of ∼5{\%} largely as a consequence of incomplete exciton dissociation.",
author = "Servaites, {Jonathan D.} and Ratner, {Mark A.} and Marks, {Tobin J.}",
year = "2009",
doi = "10.1063/1.3243986",
language = "English",
volume = "95",
journal = "Applied Physics Letters",
issn = "0003-6951",
publisher = "American Institute of Physics Publising LLC",
number = "16",

}

TY - JOUR

T1 - Practical efficiency limits in organic photovoltaic cells

T2 - Functional dependence of fill factor and external quantum efficiency

AU - Servaites, Jonathan D.

AU - Ratner, Mark A.

AU - Marks, Tobin J.

PY - 2009

Y1 - 2009

N2 - We evaluate practical power conversion efficiency limits (lim) in bulk-heterojunction organic photovoltaic (BHJ OPV) cells and how the field dependence of exciton dissociation affects cell efficiencies. We treat the fill factor limit as a function of the donor-acceptor lowest unoccupied molecular orbital offset energy (ELLO), calculating how this limit varies with decreasing ELLO. We also evaluate OPV external quantum efficiency as a function of wavelength from the optical transmittance and internal quantum efficiency limitations. For a given ELLO, we numerically optimize donor bandgap and lim and show that lim >10% should be possible for hypothetical OPV systems generating free charge carriers efficiently at ELLO ∼0.3-0.4 eV. Current BHJ OPVs with low ELLO values appear to be limited to cell efficiencies of ∼5% largely as a consequence of incomplete exciton dissociation.

AB - We evaluate practical power conversion efficiency limits (lim) in bulk-heterojunction organic photovoltaic (BHJ OPV) cells and how the field dependence of exciton dissociation affects cell efficiencies. We treat the fill factor limit as a function of the donor-acceptor lowest unoccupied molecular orbital offset energy (ELLO), calculating how this limit varies with decreasing ELLO. We also evaluate OPV external quantum efficiency as a function of wavelength from the optical transmittance and internal quantum efficiency limitations. For a given ELLO, we numerically optimize donor bandgap and lim and show that lim >10% should be possible for hypothetical OPV systems generating free charge carriers efficiently at ELLO ∼0.3-0.4 eV. Current BHJ OPVs with low ELLO values appear to be limited to cell efficiencies of ∼5% largely as a consequence of incomplete exciton dissociation.

UR - http://www.scopus.com/inward/record.url?scp=70350391650&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=70350391650&partnerID=8YFLogxK

U2 - 10.1063/1.3243986

DO - 10.1063/1.3243986

M3 - Article

AN - SCOPUS:70350391650

VL - 95

JO - Applied Physics Letters

JF - Applied Physics Letters

SN - 0003-6951

IS - 16

M1 - 163302

ER -