Supporting Information Direct Measurement of Acceptor Group ...
Supporting Information Direct Measurement of Acceptor Group Localization on Donor-Acceptor Polymers Using Resonant Auger Spectroscopy Authors: Matthew Gliboff,a Dana Sulas,b Dennis Nordlund,c Dane William deQuilettes,b Phu Nguyen,b Gerald T. Seidler, a Xiaosong Li,b David S. Ginger*b a) Department of Physics, University of Washington, Seattle, Washington 98195-1560, USA b) Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA c) Stanford Synchrotron Radiation Laboratory, 2575 Sand Hill Road MS69, Menlo Park, California 94025, USA
Corresponding Authors: David S. Ginger [email protected]
Double Repeat Unit Calculations For PCPDTBT, PCDTBT, and similar polymers, it has previously been reported that the repeat unit conformation with the thiadiazole ring anti to the thiophene units is preferred by ~1 kcal/mol.1, 2 However, it is also commonly observed that the steric strain induced by large alkyl groups causes repeat units to be anti to each other along the polymer chain.3 In fact, we observe a 69 kcal/mol stabilization for the PCPDTBT dimer when the alkyl chains extend to opposite sides of the molecule, despite syn thiadiazole and thiophene units (Figure S1). While holding this geometry for longer polymer chains, our calculations approximate the alkyl chains with methyl groups to reduce computational cost.
a.
b.
Figure S1. a) Optimized geometry of the gas phase PCPDTBT dimer with syn thiadiazole and thiophene units (3147580.66 kcal/mol) b) Optimized geometry of the gas phase PCPDTBT dimer with anti thiadiazole and thiophene units (3147511.64 kcal/mol) shows a 69 kcal/mol stabilization.
Figure S2. UV-Vis absorption spectra of neat films of PCDTBT (left) and blends of PCPDTBT with PC71BM, with and without DIO additive (right).
Figure S3. Resonant Auger spectra for a neat film PCPDTBT, a blend of PCPDTBT with PC71BM and a blend with DIO additive. Spectra are taken at the LUMO resonance with an incident x-ray energy of 398.5 eV
Core absorption spectra calculated using the BHLYP functional.
Figure S4. TD-DFT calculated N 1s x-ray absorption spectrum of the PCDTBT repeat unit using the BHLYP functional. The red lines are TD-DFT solutions corresponding to excitations from N 1s to unoccupied MOs. X-ray absorption spectra (blue solid lines) are simulated by convolving the vertical transition energies and oscillator strengths with Gaussian functions characterized by a full width at half maximum (FWHM) of 0.2 eV.
Figure S5. TD-DFT calculated N 1s x-ray absorption spectrum of the PCPDTBT repeat unit using the BHLYP functional. The red lines are TD-DFT solutions corresponding to excitations from N 1s to unoccupied MOs. X-ray absorption spectra (blue solid lines) are simulated by convolving the vertical transition energies and oscillator strengths with Gaussian functions characterized by a full width at half maximum (FWHM) of 0.2 eV. References 1. Risko, C.; McGehee, M. D.; Bredas, J.-L., A Quantum-Chemical Perspective into Low Optical-Gap Polymers for Highly-Efficient Organic Solar Cells. Chem. Sci. 2011, 7, 1200-1218. 2. Chen, H.-Y.; Hou, J.; Hayden, A. E.; Yang, H.; Houk, K. N.; Yang, Y., Silicon Atom Substitution Enhances Interchain Packing in a Thiophene-Based Polymer System. Adv. Mater. 2010, 22, 371-375. 3. Perepichka, I. F.; Perepichka, D. F., Handbook of Thiophene-Based Materials: Applications in Organic Electronics. John Wiley & Sons: Chicester, 2009.
Corresponding Authors: David S. Ginger [email protected]
Double Repeat Unit Calculations For PCPDTBT, PCDTBT, and similar polymers, it has previously been reported that the repeat unit conformation with the thiadiazole ring anti to the thiophene units is preferred by ~1 kcal/mol.1, 2 However, it is also commonly observed that the steric strain induced by large alkyl groups causes repeat units to be anti to each other along the polymer chain.3 In fact, we observe a 69 kcal/mol stabilization for the PCPDTBT dimer when the alkyl chains extend to opposite sides of the molecule, despite syn thiadiazole and thiophene units (Figure S1). While holding this geometry for longer polymer chains, our calculations approximate the alkyl chains with methyl groups to reduce computational cost.
a.
b.
Figure S1. a) Optimized geometry of the gas phase PCPDTBT dimer with syn thiadiazole and thiophene units (3147580.66 kcal/mol) b) Optimized geometry of the gas phase PCPDTBT dimer with anti thiadiazole and thiophene units (3147511.64 kcal/mol) shows a 69 kcal/mol stabilization.
Figure S2. UV-Vis absorption spectra of neat films of PCDTBT (left) and blends of PCPDTBT with PC71BM, with and without DIO additive (right).
Figure S3. Resonant Auger spectra for a neat film PCPDTBT, a blend of PCPDTBT with PC71BM and a blend with DIO additive. Spectra are taken at the LUMO resonance with an incident x-ray energy of 398.5 eV
Core absorption spectra calculated using the BHLYP functional.
Figure S4. TD-DFT calculated N 1s x-ray absorption spectrum of the PCDTBT repeat unit using the BHLYP functional. The red lines are TD-DFT solutions corresponding to excitations from N 1s to unoccupied MOs. X-ray absorption spectra (blue solid lines) are simulated by convolving the vertical transition energies and oscillator strengths with Gaussian functions characterized by a full width at half maximum (FWHM) of 0.2 eV.
Figure S5. TD-DFT calculated N 1s x-ray absorption spectrum of the PCPDTBT repeat unit using the BHLYP functional. The red lines are TD-DFT solutions corresponding to excitations from N 1s to unoccupied MOs. X-ray absorption spectra (blue solid lines) are simulated by convolving the vertical transition energies and oscillator strengths with Gaussian functions characterized by a full width at half maximum (FWHM) of 0.2 eV. References 1. Risko, C.; McGehee, M. D.; Bredas, J.-L., A Quantum-Chemical Perspective into Low Optical-Gap Polymers for Highly-Efficient Organic Solar Cells. Chem. Sci. 2011, 7, 1200-1218. 2. Chen, H.-Y.; Hou, J.; Hayden, A. E.; Yang, H.; Houk, K. N.; Yang, Y., Silicon Atom Substitution Enhances Interchain Packing in a Thiophene-Based Polymer System. Adv. Mater. 2010, 22, 371-375. 3. Perepichka, I. F.; Perepichka, D. F., Handbook of Thiophene-Based Materials: Applications in Organic Electronics. John Wiley & Sons: Chicester, 2009.
