Supporting Information. Molecular doping of a high mobility diketopyrrolopyrroledithienylthieno[3,2-b]thiophene

Transcription

1 Supporting Information Molecular doping of a high mobility diketopyrrolopyrroledithienylthieno[3,2-b]thiophene based donor-acceptor copolymer Yevhen Karpov 1,3, Tim Erdmann 1,2, Manfred Stamm 1, Uwe Lappan 1, Olga Guskova 1, Mikhail Malanin 1, Ivan Raguzin 1, Tetyana Beryozkina 4, Vasiliy Bakulev 4, Florian Günther 2,5, Sibylle Gemming 2,5,6, Gotthard Seifert 2,7, Mike Hambsch 3, Stefan Mannsfeld 2, Brigitte Voit 1,2, and Anton Kiriy 1,2 * Table S1. Conductivity of thick ~1µm blend films for PDPP(6-DO)TT and P3HT doped with F6TCNNQ at different s. Polymer doped with F6TCN NQ PDPP(6- DO)TT P3HT 0 1e-6 ±7e-8 5e-5 ±8e e-4 ±2e-5 4e-3 ±6e e-4 ±4e-5 9e-3 ±1e e-4 ±1.5e-4 2.3e-2 ±3.5e-3 Conductivity, S/cm e-3 ±6e-4 3.4e-1 ±5e e-3 ±1.9e-3 4.2e-1 ±1.6e ± ± ± ± ± ± ± ±0.31

2 Current, A 1.8m 1.5m 1.2m 900.0µ 600.0µ µ Voltage, V Figure S1. Representative I-V curves of ~50 nm-thick spin-coated films of PDPP(6- DO)TT:F6TCNNQ at different s. Linear dependencies demonstrate absence of contact effects at electric measurements.

3 Table S2. Data of resistance and conductivity of bottom-contact thin film devices for PDPP(6-DO)TT:F6TCNNQ. Bottom contact Ratio 1. 30:1 Resistance Ohm 120 min 320 min 4.85e8 3.97e9 6.02e8 2.81e9 5.80e8 3.71e min 1.40e9 1.60e9 1.72e9 200um Conductivity S/m 90 min 300 min 1.53e e e e e e min 5.34e e e-4 Resistance Ohm 120 min 320 min 8.30e8 7.30e8 2.31e8 6.27e e9 3.31e min 2.03e9 8.10e9 2.38e9 300um Conductivity S/m 90 min 320 min 4230 min 6.75e e e-3 8.9e e e e e e :1 5.40e3 5.75e3 5.45e3 1.56e4 1.55e4 1.52e4 1.38e5 1.32e5 1.25e e3 2.59e3 2.67e3 9.65e3 4.64e3 7.20e3 9.24e4 3.46e4 5.83e :1 4. 3:1 5. 1:1 1.05e4 6.33e3 7.39e3 9.58e3 6.15e3 5.65e3 2.55e4 1.98e4 1.73e4 3.10e4 1.85e4 2.21e4 3.36e4 2.90e4 1.87e4 5.33e4 3.95e4 3.43e4 3.45e5 1.73e5 2.16e5 3.79e5 3.08e5 1.48e5 1.02e5 8.10e4 6.31e e3 4.67e3 4.33e3 1.05e4 5.88e3 3.96e3 1.53e4 1.19e4 1.08e4 1.63e4 1.50e4 1.38e4 2.65e4 1.70e4 1.20e4 3.57e4 2.67e4 2.57e4 1.71e5 1.42e5 1.25e5 1.72e5 1.34e5 1.02e5 7.86e4 4.67e4 3.77e

4 Table S3. Calculated vibrational frequencies ω, scaled by a factor of for the predictions by B3LYP/6-31G(d) and the intensities for the stretching modes of the C N groups of isolated F6TCNNQ molecule, the isolated F6TCNNQ anion, the isolated F6TCNNQ 2 dianion and in two CT complexes, optimized at B3LYP/6-31G(d) level. F6-TCNNQ F6-TCNNQ:DPP-TT-DPP ω, cm -1 intensity, ω, cm km/mol intensity, km/mol F6-TCNNQ F6-TCNNQ:TT-DPP-TT F6-TCNNQ In C 2h we have three symmetry elements: σ h, C 2 and i. σ h is the symmetry plane, in which all atoms lay at all times. All vibrations are stretching modes and are restricted to the molecular plane. σ h is fulfilled for all four modes. C 2 is a two-fold rotation axis, which intersects the molecular plane in the center of the molecule. Only the two vibration modes on the left remain unchanged, if the molecule is rotated around C 2. The left two modes are of 'a'-type, the other ones of 'b'-type. i is the inversion symmetry. In C 2h the inversion center coincides with the point, in which C 2 axis and σ h plane intersects. I.e., the central C-C bond (along which two benzene rings are annulated) also indicates the inversion center. With respect to i the modes classify in the same way as with respect to C 2h. Thus we have twice a g for the two modes on the left and twice b u for the two modes on the right side (Figure 7a in the main text).

5 F6-TCNNQ F6-TCNNQ:DPP-TT-DPP F6-TCNNQ:TT-DPP-TT Wavenumber, cm -1 Figure S2. Simulated IR spectra of the C N stretching modes for the isolated F6TCNNQ molecule in the gas phase and the F6TCNNQ in two CT complexes, optimized at B3LYP/6-31G(d) level. Intensity of the neutral F6TCNNQ was multiplied by factor 10.

6 Figure S3. Changes of the bond lengths in Å; insert: the bond indices. Carbon, nitrogen and fluorine atoms are shown as grey, blue and light-blue beads, respectively. The most pronounced changes in the bond lengths occur in the elongation of the quinoid double bonds 5 and 23, connecting the side groups with the molecular core, in the shortening of the neighboring bonds 6 and 7, 21 and 22, in the shortening of four single bonds 3 and 4, 24 and 25. This results in a more aromatic structure with more equal bond lengths. The obtained results are in line with predictions by Zhu et al. and Mahns et al. for the F4TCNQ F4TCNQ transition 1. 1 a) Zhu, L.; Kim, E.-G.; Yi, Y.; Brédas, J.-L. Chem. Mater. 2011, 23, b) Mahns, Kataeva, O.; Islamov, D.; Hampel, S.; Steckel, F.; Hess, C.; Knupfer, M.; Büchner, B.; Himcinschi, C.; Hahn, T.; Renger, R.; Kortus J. Cryst. Growth Des. 2014, 14,

7 Figure S4. The surfaces of electrostatic potential of F6TCNNQ (a) and F6TCNNQ- (b). The colour bar shows the regions ranging from negative (red) to positive (blue) values of the electrostatic potential. The electrostatic potentials are plotted on an isoelectronic density surface of 0.02 e a.u.-1 Molecular electrostatic potential surface (MEPS) is a plot of electrostatic potential mapped onto the constant electron density surface. By definition, the MEP-scalar at a given point,, is an interaction energy between the electrical charge generated from the molecule electrons and a positive point charge as a probe located at, supposing that the molecule is not polarized by the test charge.2 d where is the charge of the nucleus A, that is considered to be a point charge located at, the second term is the electron density function and is a dummy integration variable. The numbers indicate the interaction energy in a.u. between positive probe on the molecule at that particular point. These values could be correlated to the electrostatic charges on the atoms with the negative number corresponding to negative charge and the positive number corresponding to positive charge. The MEPSs of the computed MEPs (Figure S6) are generated using GaussView 5 program.3 2 Leach, A.R. Molecular Modelling: Principles and Applications -2nd Ed. Pearson Education Ltd, GaussView, Version 5. R. Dennington, T. Keith and J. Millam, Semichem Inc. Shawnee Mission, KS, 2009.

8 ATR units (3to1) 0.2 (5to1) (8to1) 0.1 (10to1) (15to1) 0.02 (20to1) (30to1) Wavenumber, cm -1 Figure S5. FTIR spectrum of P3HT films doped with F6TCNNQ at different s. ATR units (30to1) (15to1) 0.1 (10to1) (8to1) 0.2 (5to1) 0.33 (3to1) 0.5 (2to1) 1 (1to1) Wavenumber, cm-1 Figure S6. FTIR spectrum of PDPP(6-DO)T2 films doped with F6TCNNQ at different s.

9 Figure S7. Picture of the bottom contact substrate with deposited gold contacts and spin coated polymer film on it (top view). 300 µm distance between contacts on the right side of the picture and 200 µm on the top-left.

10 Figure S8. Comparison of calculated charge transfer degrees and complex formation energies obtained from PBE/DZP single point calculations for the CT complex F6TCNNQ:DPP-TT- DPP obtained for two fixed distances in z-direction: 3 Å (dashed lines) and 3.5 Å (solid lines). The colored curves specify the CT obtained by the different population analyses (left scale) and the energies of the complex relative to the individual molecules is given in black (right scale). The energies of the stable configurations are represented by bars. Increase of the distances by 0.5 Å leads to decrease of the CT efficiency by electrons and decrease of the stabilization energies up to 50 kj/mol, however the general trends are preserved. Figure S9. Comparison of calculated charge transfer degrees and complex formation energies obtained from PBE/DZP single point calculations for three CT complexes F6TCNNQ:DPP- TT-DPP as a function of z-distances: In the first and second cases (dotted and dashed lines), the long axis of the dopant is aligned to the polymer direction while in the third case the dopant is rotated by 44 according to the most stable rotation depicted in Figure S8.