Abstract
We present time-resolved photo luminescence studies in conjunction with device characterization of a variety of heterojunctions with poly-(3-hexylthiophene), or P3HT, as a means to understand how exciton dynamics affect device performance. We find that blends of P3HT with the electron-transporting polymer CN-ether-PPV and with the fullerene derivative PCBM result in ∼4-fold and ∼15-fold improvements in short-circuit currents, respectively, over neat-film P3HT on TiO 2 solgel. Despite efficient charge-transfer in P3HT:PCBM films, as evidenced by enhanced device performance and quenched steady-state luminescence, we observe only moderate reduction of the excited state lifetime, due to the already efficient non-radiative pathways in P3HT. We observe evidence for a new state that we assign to an exciplex in blends of P3HT with the electron-transporting polymer CN-ether-PPV. The exciplex state, which confirms the existence of charge-transfer between the two polymers, may account for the enhanced device performance of these blends by acting as a scavenger for excitons that would otherwise decay rapidly via non-radiative pathways. The long-range order of P3HT is disrupted when spin-cast on rough TiO 2 nanoparticles, and this results in a blueshift of the PL spectrum and a new long-lived decay component that we attribute to long-lived intrachain polarons. P3HT on smooth TiO 2 solgel films shows little or no quenching of the excited state, despite known charge transfer from P3HT to TiO 2.
| Original language | English |
|---|---|
| Title of host publication | Proceedings of SPIE - The International Society for Optical Engineering |
| Editors | Z.H Kafafi, P.A. Lane |
| Pages | 1-11 |
| Number of pages | 11 |
| Volume | 5938 |
| DOIs | |
| Publication status | Published - 2005 |
| Event | Organic Photovoltaics VI - San Diego, CA, United States Duration: Aug 2 2005 → Aug 4 2005 |
Other
| Other | Organic Photovoltaics VI |
|---|---|
| Country | United States |
| City | San Diego, CA |
| Period | 8/2/05 → 8/4/05 |
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Keywords
- CN-ether-PPV
- Conjugated polymers
- Fullerene
- P3HT
- PCBM
- Photovoltaic effect
- Plastic electronics
- Polymer solar cell
- Time-resolved photoluminescence
- Titanium dioxide
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Condensed Matter Physics
Cite this
Exciton dynamics and device performance in polythiophene heterojunctions for photovoltaics. / Chasteen, Stephanie V.; Carter, Sue A.; Rumbles, Gary.
Proceedings of SPIE - The International Society for Optical Engineering. ed. / Z.H Kafafi; P.A. Lane. Vol. 5938 2005. p. 1-11 59380J.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Exciton dynamics and device performance in polythiophene heterojunctions for photovoltaics
AU - Chasteen, Stephanie V.
AU - Carter, Sue A.
AU - Rumbles, Gary
PY - 2005
Y1 - 2005
N2 - We present time-resolved photo luminescence studies in conjunction with device characterization of a variety of heterojunctions with poly-(3-hexylthiophene), or P3HT, as a means to understand how exciton dynamics affect device performance. We find that blends of P3HT with the electron-transporting polymer CN-ether-PPV and with the fullerene derivative PCBM result in ∼4-fold and ∼15-fold improvements in short-circuit currents, respectively, over neat-film P3HT on TiO 2 solgel. Despite efficient charge-transfer in P3HT:PCBM films, as evidenced by enhanced device performance and quenched steady-state luminescence, we observe only moderate reduction of the excited state lifetime, due to the already efficient non-radiative pathways in P3HT. We observe evidence for a new state that we assign to an exciplex in blends of P3HT with the electron-transporting polymer CN-ether-PPV. The exciplex state, which confirms the existence of charge-transfer between the two polymers, may account for the enhanced device performance of these blends by acting as a scavenger for excitons that would otherwise decay rapidly via non-radiative pathways. The long-range order of P3HT is disrupted when spin-cast on rough TiO 2 nanoparticles, and this results in a blueshift of the PL spectrum and a new long-lived decay component that we attribute to long-lived intrachain polarons. P3HT on smooth TiO 2 solgel films shows little or no quenching of the excited state, despite known charge transfer from P3HT to TiO 2.
AB - We present time-resolved photo luminescence studies in conjunction with device characterization of a variety of heterojunctions with poly-(3-hexylthiophene), or P3HT, as a means to understand how exciton dynamics affect device performance. We find that blends of P3HT with the electron-transporting polymer CN-ether-PPV and with the fullerene derivative PCBM result in ∼4-fold and ∼15-fold improvements in short-circuit currents, respectively, over neat-film P3HT on TiO 2 solgel. Despite efficient charge-transfer in P3HT:PCBM films, as evidenced by enhanced device performance and quenched steady-state luminescence, we observe only moderate reduction of the excited state lifetime, due to the already efficient non-radiative pathways in P3HT. We observe evidence for a new state that we assign to an exciplex in blends of P3HT with the electron-transporting polymer CN-ether-PPV. The exciplex state, which confirms the existence of charge-transfer between the two polymers, may account for the enhanced device performance of these blends by acting as a scavenger for excitons that would otherwise decay rapidly via non-radiative pathways. The long-range order of P3HT is disrupted when spin-cast on rough TiO 2 nanoparticles, and this results in a blueshift of the PL spectrum and a new long-lived decay component that we attribute to long-lived intrachain polarons. P3HT on smooth TiO 2 solgel films shows little or no quenching of the excited state, despite known charge transfer from P3HT to TiO 2.
KW - CN-ether-PPV
KW - Conjugated polymers
KW - Fullerene
KW - P3HT
KW - PCBM
KW - Photovoltaic effect
KW - Plastic electronics
KW - Polymer solar cell
KW - Time-resolved photoluminescence
KW - Titanium dioxide
UR - http://www.scopus.com/inward/record.url?scp=31744437773&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=31744437773&partnerID=8YFLogxK
U2 - 10.1117/12.614243
DO - 10.1117/12.614243
M3 - Conference contribution
AN - SCOPUS:31744437773
VL - 5938
SP - 1
EP - 11
BT - Proceedings of SPIE - The International Society for Optical Engineering
A2 - Kafafi, Z.H
A2 - Lane, P.A.
ER -