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 language | English |
|---|---|
| Article number | 163302 |
| Journal | Applied Physics Letters |
| Volume | 95 |
| Issue number | 16 |
| DOIs | |
| Publication status | Published - 2009 |
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ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)
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Practical efficiency limits in organic photovoltaic cells : Functional dependence of fill factor and external quantum efficiency. / Servaites, Jonathan D.; Ratner, Mark A.; Marks, Tobin J.
In: Applied Physics Letters, Vol. 95, No. 16, 163302, 2009.Research output: Contribution to journal › Article
}
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.
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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 -