Abstract
Zinc oxide is a promising candidate as an interfacial layer (IFL) in inverted organic photovoltaic (OPV) cells due to the n-type semiconducting properties as well as chemical and environmental stability. Such ZnO layers collect electrons at the transparent electrode, typically indium tin oxide (ITO). However, the significant resistivity of ZnO IFLs and an energetic mismatch between the ZnO and the ITO layers hinder optimum charge collection. Here we report that inserting nanoscopic copper hexadecafluorophthalocyanine (F16CuPc) layers, as thin films or nanowires, between the ITO anode and the ZnO IFL increases OPV performance by enhancing interfacial electron transport. In inverted P3HT:PC61BM cells, insertion of F 16CuPc nanowires increases the short circuit current density (J sc) versus cells with only ZnO layers, yielding an enhanced power conversion efficiency (PCE) of ∼3.6% vs ∼3.0% for a control without the nanowire layer. Similar effects are observed for inverted PTB7:PC71BM cells where the PCE is increased from 8.1% to 8.6%. X-ray scattering, optical, and electrical measurements indicate that the performance enhancement is ascribable to both favorable alignment of the nanowire π-π stacking axes parallel to the photocurrent flow and to the increased interfacial layer-active layer contact area. These findings identify a promising strategy to enhance inverted OPV performance by inserting anisotropic nanostructures with π-π stacking aligned in the photocurrent flow direction.
| Original language | English |
|---|---|
| Pages (from-to) | 6315-6321 |
| Number of pages | 7 |
| Journal | Nano Letters |
| Volume | 12 |
| Issue number | 12 |
| DOIs | |
| Publication status | Published - Dec 12 2012 |
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Keywords
- copper hexadecaphthalocyanine
- interfacial layers
- nanowire
- Organic solar cell
- zinc oxide
ASJC Scopus subject areas
- Condensed Matter Physics
- Bioengineering
- Chemistry(all)
- Materials Science(all)
- Mechanical Engineering
Cite this
Fluorinated copper phthalocyanine nanowires for enhancing interfacial electron transport in organic solar cells. / Yoon, Seok Min; Lou, Sylvia J.; Loser, Stephen; Smith, Jeremy; Chen, Lin X.; Facchetti, Antonio; Marks, Tobin J.
In: Nano Letters, Vol. 12, No. 12, 12.12.2012, p. 6315-6321.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Fluorinated copper phthalocyanine nanowires for enhancing interfacial electron transport in organic solar cells
AU - Yoon, Seok Min
AU - Lou, Sylvia J.
AU - Loser, Stephen
AU - Smith, Jeremy
AU - Chen, Lin X.
AU - Facchetti, Antonio
AU - Marks, Tobin J
PY - 2012/12/12
Y1 - 2012/12/12
N2 - Zinc oxide is a promising candidate as an interfacial layer (IFL) in inverted organic photovoltaic (OPV) cells due to the n-type semiconducting properties as well as chemical and environmental stability. Such ZnO layers collect electrons at the transparent electrode, typically indium tin oxide (ITO). However, the significant resistivity of ZnO IFLs and an energetic mismatch between the ZnO and the ITO layers hinder optimum charge collection. Here we report that inserting nanoscopic copper hexadecafluorophthalocyanine (F16CuPc) layers, as thin films or nanowires, between the ITO anode and the ZnO IFL increases OPV performance by enhancing interfacial electron transport. In inverted P3HT:PC61BM cells, insertion of F 16CuPc nanowires increases the short circuit current density (J sc) versus cells with only ZnO layers, yielding an enhanced power conversion efficiency (PCE) of ∼3.6% vs ∼3.0% for a control without the nanowire layer. Similar effects are observed for inverted PTB7:PC71BM cells where the PCE is increased from 8.1% to 8.6%. X-ray scattering, optical, and electrical measurements indicate that the performance enhancement is ascribable to both favorable alignment of the nanowire π-π stacking axes parallel to the photocurrent flow and to the increased interfacial layer-active layer contact area. These findings identify a promising strategy to enhance inverted OPV performance by inserting anisotropic nanostructures with π-π stacking aligned in the photocurrent flow direction.
AB - Zinc oxide is a promising candidate as an interfacial layer (IFL) in inverted organic photovoltaic (OPV) cells due to the n-type semiconducting properties as well as chemical and environmental stability. Such ZnO layers collect electrons at the transparent electrode, typically indium tin oxide (ITO). However, the significant resistivity of ZnO IFLs and an energetic mismatch between the ZnO and the ITO layers hinder optimum charge collection. Here we report that inserting nanoscopic copper hexadecafluorophthalocyanine (F16CuPc) layers, as thin films or nanowires, between the ITO anode and the ZnO IFL increases OPV performance by enhancing interfacial electron transport. In inverted P3HT:PC61BM cells, insertion of F 16CuPc nanowires increases the short circuit current density (J sc) versus cells with only ZnO layers, yielding an enhanced power conversion efficiency (PCE) of ∼3.6% vs ∼3.0% for a control without the nanowire layer. Similar effects are observed for inverted PTB7:PC71BM cells where the PCE is increased from 8.1% to 8.6%. X-ray scattering, optical, and electrical measurements indicate that the performance enhancement is ascribable to both favorable alignment of the nanowire π-π stacking axes parallel to the photocurrent flow and to the increased interfacial layer-active layer contact area. These findings identify a promising strategy to enhance inverted OPV performance by inserting anisotropic nanostructures with π-π stacking aligned in the photocurrent flow direction.
KW - copper hexadecaphthalocyanine
KW - interfacial layers
KW - nanowire
KW - Organic solar cell
KW - zinc oxide
UR - http://www.scopus.com/inward/record.url?scp=84870893019&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84870893019&partnerID=8YFLogxK
U2 - 10.1021/nl303419n
DO - 10.1021/nl303419n
M3 - Article
C2 - 23181741
AN - SCOPUS:84870893019
VL - 12
SP - 6315
EP - 6321
JO - Nano Letters
JF - Nano Letters
SN - 1530-6984
IS - 12
ER -