TY - JOUR
T1 - Self-Assembling Tripodal Small-Molecule Donors for Bulk Heterojunction Solar Cells
AU - Aytun, Taner
AU - Santos, Peter J.
AU - Bruns, Carson J.
AU - Huang, Dongxu
AU - Koltonow, Andrew R.
AU - Olvera De La Cruz, Monica
AU - Stupp, Samuel I.
N1 - Funding Information:
This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award No. DE-FG02-00ER45810 (S.I.S.) except for the computer simulation work, which was supported by Northwestern University Materials Research and Engineering Center (NU-MRSEC) funded by the NSF Under Award No. DMR-1121262 (MOC). P.J.S. acknowledges support from the Northwestern Undergraduate Summer Research Grant, the Meister Family Undergraduate Research Grant, and the McCormick Undergraduate Research Grant. A.R.K. acknowledges support by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1324585. The authors are also grateful to the following shared facilities at Northwestern University: IMSERC, Keck Biophysics, and the NIFTI facility of NUANCE Center. NUANCE Center is supported by NSF-NSEC, NSFMRSEC, the Keck Foundation, the State of Illinois, and Northwestern University; IMSERC NMR usage under Award NSF CHE-1048773 is appreciated. Use of Advanced Photon Source sector 8-ID-E, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357. The authors also thank Dr. Liam Palmer for fruitful discussions and help with the manuscript, Dr. G. Shekhawat for his help with AFM measurements and Dr. J. Strzalka for GIXD measurements at Argonne National Laboratory.
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/2/25
Y1 - 2016/2/25
N2 - The power conversion efficiency of organic solar cells (OSCs) could benefit from systematic studies to improve bulk heterojunction (BHJ) morphology by modifying donor compounds. Supramolecular self-assembly is an attractive strategy to combine the beneficial properties of polymeric donors, such as a well-controlled morphology, with the homogeneous composition of small molecule donors for OSCs. We report here on two tripodal "star-shaped" small-molecule donor compounds based on diketopyrrolopyrrole (DPP) side chains for solution-processed BHJ OSCs. The tripod molecules were found not to aggregate in solution or form crystalline domains in thin films when a branched alkyl chain (2-ethylhexyl) substituent was used, whereas linear (docedecyl) alkyl chains promote the formation of one-dimensional (1D) nanowires and more crystalline domains in the solid state. We demonstrate that the 1D self-assembly of these tripods enhances the performance of the corresponding solution-processed OSCs by 50%, which is attributed to the significant increase in the fill factor of devices resulting from a reduction of trap states.
AB - The power conversion efficiency of organic solar cells (OSCs) could benefit from systematic studies to improve bulk heterojunction (BHJ) morphology by modifying donor compounds. Supramolecular self-assembly is an attractive strategy to combine the beneficial properties of polymeric donors, such as a well-controlled morphology, with the homogeneous composition of small molecule donors for OSCs. We report here on two tripodal "star-shaped" small-molecule donor compounds based on diketopyrrolopyrrole (DPP) side chains for solution-processed BHJ OSCs. The tripod molecules were found not to aggregate in solution or form crystalline domains in thin films when a branched alkyl chain (2-ethylhexyl) substituent was used, whereas linear (docedecyl) alkyl chains promote the formation of one-dimensional (1D) nanowires and more crystalline domains in the solid state. We demonstrate that the 1D self-assembly of these tripods enhances the performance of the corresponding solution-processed OSCs by 50%, which is attributed to the significant increase in the fill factor of devices resulting from a reduction of trap states.
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U2 - 10.1021/acs.jpcc.5b10064
DO - 10.1021/acs.jpcc.5b10064
M3 - Article
AN - SCOPUS:84959273329
VL - 120
SP - 3602
EP - 3611
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 7
ER -