TY - JOUR
T1 - Symmetry-Breaking Charge Separation in the Solid State
T2 - Tetra(phenoxy)perylenediimide Polycrystalline Films
AU - Ramirez, Carolyn E.
AU - Chen, Su
AU - Powers-Riggs, Natalia E.
AU - Schlesinger, Itai
AU - Young, Ryan M.
AU - Wasielewski, Michael R.
N1 - Funding Information:
This work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award DE-FG02-99ER14999 (M.R.W.). This work made use of the IMSERC at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205), the State of Illinois, and the International Institute for Nanotechnology (IIN). This work also made use of the Keck-II facility of Northwestern University’s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. X-ray scattering measurements were performed using Beamline 8-ID-E at the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract DE-AC02-06CH11357. X-ray diffraction measurements were performed using the Jerome B. Cohen X-ray Diffraction Facility supported by the MRSEC program of the National Science Foundation (DMR-1720139) at the Materials Research Center of Northwestern University and the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205). C.R. thanks Dr. Michelle Chen and Paige Brown for discussion and support with experiments as well as Dr. Stephen A. Miller and the Northwestern University Laser and Electronics Design Core Facility for instrumentation consultation.
Publisher Copyright:
© 2020 Journal of the American Chemical Society. All right reserved.
PY - 2020/10/21
Y1 - 2020/10/21
N2 - Generation of electron-hole pairs via symmetry-breaking charge separation (SB-CS) in photoexcited assemblies of organic chromophores is a potentially important route to enhancing the open-circuit voltage of organic photovoltaics. While most reports of SB-CS have focused on molecular dimers in solution where the environmental polarity can be manipulated, here, we investigate SB-CS in polycrystalline thin films of 1,6,7,12-tetra(phenoxy)perylene-3,4:9,10-bis(dicarboximide) having either n-octyl groups (octyl-tpPDI) or hydrogen atoms (H-tpPDI) attached to its imide nitrogen atoms. Structural analyses using various X-ray techniques reveal that while both compounds show π-πstacking in thin films, H-tpPDI is more slip-stacked than octyl-tpPDI and has intermolecular hydrogen bonds to its neighboring molecules. Transient absorption spectroscopy shows that octyl-tpPDI exhibits strong mixing between its singlet excited state and a charge transfer state, yielding an excimer-like state, while H-tpPDI undergoes nearly quantitative SB-CS, making the latter a promising candidate for use in organic photovoltaic devices.
AB - Generation of electron-hole pairs via symmetry-breaking charge separation (SB-CS) in photoexcited assemblies of organic chromophores is a potentially important route to enhancing the open-circuit voltage of organic photovoltaics. While most reports of SB-CS have focused on molecular dimers in solution where the environmental polarity can be manipulated, here, we investigate SB-CS in polycrystalline thin films of 1,6,7,12-tetra(phenoxy)perylene-3,4:9,10-bis(dicarboximide) having either n-octyl groups (octyl-tpPDI) or hydrogen atoms (H-tpPDI) attached to its imide nitrogen atoms. Structural analyses using various X-ray techniques reveal that while both compounds show π-πstacking in thin films, H-tpPDI is more slip-stacked than octyl-tpPDI and has intermolecular hydrogen bonds to its neighboring molecules. Transient absorption spectroscopy shows that octyl-tpPDI exhibits strong mixing between its singlet excited state and a charge transfer state, yielding an excimer-like state, while H-tpPDI undergoes nearly quantitative SB-CS, making the latter a promising candidate for use in organic photovoltaic devices.
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U2 - 10.1021/jacs.0c09185
DO - 10.1021/jacs.0c09185
M3 - Article
C2 - 33021786
AN - SCOPUS:85094220879
VL - 142
SP - 18243
EP - 18250
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 42
ER -