Abstract
Using small-molecule donor (SMD) semiconductors in organic photovoltaics (OPVs) has historically afforded lower power conversion efficiencies (PCEs) than their polymeric counterparts. The PCE difference is attributed to shorter conjugated backbones, resulting in reduced intermolecular interactions. Here, a new pair of SMDs is synthesized based on the diketopyrrolopyrrole-benzodithiophene-diketopyrrolopyrrole (BDT-DPP2) skeleton but having fluorinated and fluorine-free aromatic side-chain substituents. Ternary OPVs having varied ratios of the two SMDs with PC61BM as the acceptor exhibit tunable open-circuit voltages (Vocs) between 0.833 and 0.944 V due to a fluorination-induced shift in energy levels and the electronic "alloy" formed from the miscibility of the two SMDs. A 15% increase in PCE is observed at the optimal ternary SMD ratio, with the short-circuit current density (Jsc) significantly increased to 9.18 mA/cm2. The origin of Jsc enhancement is analyzed via charge generation, transport, and diffuse reflectance measurements, and is attributed to increased optical absorption arising from a maximum in film crystallinity at this SMD ratio, observed by grazing incidence wide-angle X-ray scattering.
| Original language | English |
|---|---|
| Pages (from-to) | 1690-1697 |
| Number of pages | 8 |
| Journal | ACS Energy Letters |
| Volume | 2 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - Jul 14 2017 |
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ASJC Scopus subject areas
- Chemistry (miscellaneous)
- Energy Engineering and Power Technology
- Fuel Technology
- Renewable Energy, Sustainability and the Environment
- Materials Chemistry
Cite this
Enhanced Light Absorption in Fluorinated Ternary Small-Molecule Photovoltaics. / Eastham, Nicholas D.; Dudnik, Alexander S.; Harutyunyan, Boris; Aldrich, Thomas J.; Leonardi, Matthew J.; Manley, Eric F.; Butler, Melanie R.; Harschneck, Tobias; Ratner, Mark A; Chen, Lin X.; Bedzyk, Michael J.; Melkonyan, Ferdinand S.; Facchetti, Antonio; Chang, Robert P. H.; Marks, Tobin J.
In: ACS Energy Letters, Vol. 2, No. 7, 14.07.2017, p. 1690-1697.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Enhanced Light Absorption in Fluorinated Ternary Small-Molecule Photovoltaics
AU - Eastham, Nicholas D.
AU - Dudnik, Alexander S.
AU - Harutyunyan, Boris
AU - Aldrich, Thomas J.
AU - Leonardi, Matthew J.
AU - Manley, Eric F.
AU - Butler, Melanie R.
AU - Harschneck, Tobias
AU - Ratner, Mark A
AU - Chen, Lin X.
AU - Bedzyk, Michael J.
AU - Melkonyan, Ferdinand S.
AU - Facchetti, Antonio
AU - Chang, Robert P. H.
AU - Marks, Tobin J
PY - 2017/7/14
Y1 - 2017/7/14
N2 - Using small-molecule donor (SMD) semiconductors in organic photovoltaics (OPVs) has historically afforded lower power conversion efficiencies (PCEs) than their polymeric counterparts. The PCE difference is attributed to shorter conjugated backbones, resulting in reduced intermolecular interactions. Here, a new pair of SMDs is synthesized based on the diketopyrrolopyrrole-benzodithiophene-diketopyrrolopyrrole (BDT-DPP2) skeleton but having fluorinated and fluorine-free aromatic side-chain substituents. Ternary OPVs having varied ratios of the two SMDs with PC61BM as the acceptor exhibit tunable open-circuit voltages (Vocs) between 0.833 and 0.944 V due to a fluorination-induced shift in energy levels and the electronic "alloy" formed from the miscibility of the two SMDs. A 15% increase in PCE is observed at the optimal ternary SMD ratio, with the short-circuit current density (Jsc) significantly increased to 9.18 mA/cm2. The origin of Jsc enhancement is analyzed via charge generation, transport, and diffuse reflectance measurements, and is attributed to increased optical absorption arising from a maximum in film crystallinity at this SMD ratio, observed by grazing incidence wide-angle X-ray scattering.
AB - Using small-molecule donor (SMD) semiconductors in organic photovoltaics (OPVs) has historically afforded lower power conversion efficiencies (PCEs) than their polymeric counterparts. The PCE difference is attributed to shorter conjugated backbones, resulting in reduced intermolecular interactions. Here, a new pair of SMDs is synthesized based on the diketopyrrolopyrrole-benzodithiophene-diketopyrrolopyrrole (BDT-DPP2) skeleton but having fluorinated and fluorine-free aromatic side-chain substituents. Ternary OPVs having varied ratios of the two SMDs with PC61BM as the acceptor exhibit tunable open-circuit voltages (Vocs) between 0.833 and 0.944 V due to a fluorination-induced shift in energy levels and the electronic "alloy" formed from the miscibility of the two SMDs. A 15% increase in PCE is observed at the optimal ternary SMD ratio, with the short-circuit current density (Jsc) significantly increased to 9.18 mA/cm2. The origin of Jsc enhancement is analyzed via charge generation, transport, and diffuse reflectance measurements, and is attributed to increased optical absorption arising from a maximum in film crystallinity at this SMD ratio, observed by grazing incidence wide-angle X-ray scattering.
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U2 - 10.1021/acsenergylett.7b00486
DO - 10.1021/acsenergylett.7b00486
M3 - Article
VL - 2
SP - 1690
EP - 1697
JO - ACS Energy Letters
JF - ACS Energy Letters
SN - 2380-8195
IS - 7
ER -