@inproceedings{1266fe059876405bbae8628988f0deab,
title = "Triphenylamine-based star-shaped absorbers with tunable energy levels for organic photovoltaics",
abstract = "A new family of soluble low-bandgap star-shaped molecules based upon triphenylamine (TPA) and containing benzothiadiazole (BTD) acceptor moieties have been designed and synthesized for organic photovoltaic (OPV) applications. The design results in the lowest unoccupied molecular orbital (LUMO) being spatially distributed on the periphery of the molecule, allowing facile photo-induced electron transfer to the fullerene phenyl C61 butyric acid methyl ester (PCBM). Photoluminescence quenching studies indicate efficient quenching of excitons, while time-resolved microwave conductivity experiments demonstrate effective separation of charges. Adjunct electron-withdrawing moieties allow tuning of the LUMO level. Theoretical calculations indicate three derivatives with LUMO levels in varying proximity to that of PCBM, which allows empirical testing of the theorized need for a 0.3 eV LUMO offset to ensure efficient charge transfer to PCBM. Design, characterization and bulk heterojunction device results for the new materials will be presented.",
author = "Hammond, {Scott R.} and Andres Garcia and Alexandre Nardes and Eric Knoll and Muhammet Kose and Ross Larsen and Nikos Kopidakis and Zbyslaw Owczarczyk and Olson, {Dana C.} and Ginley, {David S.}",
year = "2010",
doi = "10.1109/PVSC.2010.5616496",
language = "English",
isbn = "9781424458905",
series = "Photovoltaic Specialists Conference",
publisher = "Institute of Electrical and Electronics Engineers (IEEE)",
pages = "1607--1610",
booktitle = "35th IEEE Photovoltaic Specialists Conference",
address = "United States",
note = "35th IEEE Photovoltaic Specialists Conference, PVSC 2010 ; Conference date: 20-06-2010 Through 25-06-2010",
}