Defect free naphthalene diimide bithiophene copolymers with controlled molar mass and high performance via direct arylation polycondensation

Transcription

1 upporting information for Defect free naphthalene diimide bithiophene copolymers with controlled molar mass and high performance via direct arylation polycondensation ukiya Matsidik 1,2, Hartmut Komber *, Alessandro Luzio 4, Mario Caironi 4, Michael ommer 1,2 * 1 Universität Freiburg, Makromolekulare Chemie, tefan Meier tr. 1, 9104 Freiburg, Germany 2 Freiburger Materialforschungszentrum, tefan Meier tr. 21, Universität Freiburg, 9104 Freiburg, Germany Leibniz Institut für Polymerforschung Dresden e.v., Hohe traße 6, Dresden, Germany 4 Center for anoscience and Instituto Italiano di Tecnologia, Via Pascoli 0/, 201 Milano, Italy Content 1. ynthesis and Instrumentation (pages 2 ) 2. ynthesis and 1 H and 1 C M data of DI derivatives (pages 4 9). Assignment of end group signals and signals of structural defects (DI DI and T2 T2 homocoupling) in the 1 H M spectra of PDIT2 synthesized by DAP (pages 10 19) 4. ummary of chemical shifts of end groups and homocoupled species (page 20) 5. 1 H M spectra of selected PDIT2 samples from Table 1 (pages 21 2) 6. Thermal characterization (pages 24 25). Additional electrical characterization (page 26) 8. Additional UV vis spectra (page 2) 1

2 1. ynthesis and Instrumentation 1.1. ynthesis. Materials. All chemicals were obtained from igma Aldrich and used without further treatment unless otherwise stated. Pd 2 dba was obtained from igma Aldrich in 9 % purity and was used as received, and stored under ambient conditions. p. a. grade toluene was distilled over sodium and stored over molecular sieve (A4). Monomer DIBr 2 was made according to previously reported method. 1 2,2 bithiophene (T 2 ) was purchased from Alfa Aesar (98%) and further purified by eluting through a silica plug with isohexane. DIBr was made according to a protocol of Jones et al. 2 PDIT4 was made according to Gann et al. General preparation of PDIT2 via DAP (data for entry 18). T 2 (49.9 mg, 0. mmol), DIBr 2 (295.5 mg, 0. mmol), K 2 C (124.9 mg, 0.9 mmol), and pivalic acid (0.64 mg, 0. mmol) were carefully weighed into a dry vial containing a stirr bar. 0.6 ml degassed dry toluene was added under a 2 atmosphere and the whole was stirred for 5 min at T in order to fully dissolve the monomers. Then Pd 2 dba (2.5 mg, 0.00 mmol) was added under nitrogen. The vial was sealed and placed into a preheated oil bath and stirred for 14 h at 100 C. After cooling to T, the material was dissolved in 20 ml CHCl, precipitated into 200ml methanol, filtered and purified via oxhlet extraction with acetone, ethyl acetate, and hexanes (until colorlessness of the extracted solution). The material was finally collected with CHCl and filtered through a silica gel plug to give 296 mg PDIT2 in 100 % yield. EC (298 K, CHCl ): M n = 5 kda, M w = 124 kda, Đ=.54. tille polycondensation of PDIT2 was performed according to Watson et al. 4 Different molar masses were obtained by using different monomer purities Instrumentation GPC measurements were carried out on four DV gel 5 μm columns, with pore sizes ranging from 10 to 10 6 Å (P), connected in series with a Knauer K 201 I detector, and calibrated with polystyrene standards. CHCl was used as eluent at room temperature at a flow rate of 1.0 ml/min. UV Vis measurements were carried out on a Perkin Elmer λ1050 spectrophotometer, using a tungsten lamp as the excitation source. M spectroscopy. 1 H (500.1 MHz) and 1 C (125. MHz) M spectra were recorded on a Bruker Avance III spectrometer using a 5 mm gradient probe. CDCl was used as solvent for the 1 H and 1 C M characterization of model compounds. These measurements were carried out at 0 C. 1 H M spectra of polymers and model compounds were obtained from C 2 D 2 Cl 4 solutions at 120 C. The solvents were used as chemical shift reference (CDCl : δ( 1 H) =.26 ppm, δ( 1 C) =.0 ppm; C 2 D 2 Cl 4 : δ( 1 H) = 5.98 ppm).the 1 H and 1 C M signal assignments of model compounds were supported by the evaluation of 2D M spectra (TCY, EY, HQC, HMQC). DC measurements were acquired on a ETZCH DC 204 F1 Phoenix under a nitrogen atmosphere at a heating and cooling rate of 10 C.min 1. 2

3 1.. FETs fabrication and characterization chemes of the off center spin coating process (a) and the final FET structure (b). Thoroughly cleaned 1F glass or i2 were used as substrates for all the films realized in this work. FETs were fabricated according to a top gate, bottom contact architecture. Bottom Au contacts were defined by a liftoff photolithographic process with a 0. nm thick Cr adhesion layer. The thickness of the Au contacts was 0 nm. Patterned substrates were cleaned in an ultrasonic bath in isopropyl alcohol for 2 min before deposition of the semiconductor or the dielectric. olutions of PDIT2 were prepared in toluene (5 g/l), filtered and deposited by off center spin coating at 1000 rpm for 0 s in air, keeping a distance of the ource () and Drain (D) pattern from the spin coating center of.5 cm. The device was then annealed for 14 h at 120 C on a hot plate in a nitrogen atmosphere. PMMA (igma Aldrich) with M w = 120 kda was spun from n butyl acetate (with a concentration of 80 g/l). A dielectric layer thickness of nm was obtained. After the deposition of the dielectric, the devices were annealed under nitrogen at 80 C for 1 h. 50 nm thick Al electrodes were thermally evaporated as gate contacts. The final FET structure is shown above. The electrical characteristics of transistors were measured in a nitrogen glovebox on a Wentworth Laboratories probe station with an Agilent B1500A semiconductor device analyzer. aturation charge carrier mobility values were extracted by the transfer characteristic curves according to the expression I D = µ sat C die W/2L (V G V th ) 2, where I D is the drain current, µ sat is the saturation mobility, C die is the specific dielectric capacitance, W (2 mm) and L (20 µm) are the width and the length of the channel, respectively, V G is the gate voltage, V D is the drain voltage and V t is the threshold voltage. Accordingly, the V G dependent values of µ sat were obtained from the slope of I D 0.5 versus V G, calculated every three points around each V g value. As a reference, FETs fabricated with standard spin coating process using the DAP synthesized batch with M n = 1 kda display mobility values ranging from 0.1 cm 2 /Vs to 0.6 cm 2 /Vs.

4 2. ynthesis and M characterization of DI derivatives The alkyl substituent is 2 octyldodecyl for all model compounds. nly the 1 H and 1 C chemical shifts of the CH 2 group vary with the DI substitution pattern and were reported for each compound. All other 1 C chemical shifts vary only within ± 0.5 ppm and are reported here for all compounds. c' d' e' f' g' h' a b CH 2 CH 2 (CH 2 ) CH 2 CH 2 CH ' = CH 2 CH CH 2 CH 2 (CH 2 ) 5 CH 2 CH 2 CH c d e f g h 1 H M (CDCl ): (a), (m, b), (c g,c g ), ppm (h,h ). 1 C M (CDCl ): (a), 6.5 (b), 1.9 and 1. (f,f ), 1. (c,c ), (e,e ), 26.4 (d,d ), 22. (g,g ), 14.1 ppm (h,h ) DI pivaloate Under an 2 atmosphere, a mixture of DIBr (59.18 mg, mmol) and PivK (2.6 mg, mmol) was dissolved in 1 ml of degassed dry DMAc in a high pressure vial. The vial was placed in a preheated oil bath to 80 C and stirred for 0 h. After the mixture was cooled to room temperature, it was purified by flash chromatography (dichloromethane/ isohexane = 1:1) to afford 1% (10 mg) of DI pivaloate (2.1.) and 60 % ( mg) of H DI (2.2.) as orange yellow solids. (CH ) C C H M (CDCl ): 8.9 (d,.6 Hz; ), 8.2 (d,.6 Hz; 6), 8. (s; ), 4.14 and 4.09 (CH 2 ), 1.51 ppm (25). 1 C M (CDCl ): (2), 16.0 (1), (12), (14), (11), (2), 11.6 (), (6), (), (9), (4), (8), (5), (10), (1), and (CH 2 ), 9.46 (24), 2.20 ppm (25). 4

5 2.2. H DI (synthesis see 2.1.) H H M (CDCl ): (s; H), 8. (d,. Hz; ), 8.56 (d,. Hz; 6), 8.1 (s; ), 4.14 and 4.12 ppm (CH 2 ). 1 C M (CDCl ): 168. (11), (2), (1), (12), (14), (), (4), (9), (6), (5), (), (8), (10), (1), and ppm (CH 2 ). 2.. Tol DI (mixture of isomers) Under an 2 atmosphere, a mixture of DIBr (0 mg, 0.0 mmol), K 2 C (1.68 mg, 0.91 mmol) and PivH (. mg, 0.0 mmol) was dissolved in 0.66 ml of degassed dry toluene in a high pressure vial, followed by the addition of Pd 2 dba (0. mg, 1 mol%). The vial was placed in a preheated oil bath to 100 C and stirred for 2 h. After cooling to room temperature, the solvent was removed by evaporation. The residue was taken up in CHCl, filtered through a silica plug, concentrated and dried, and the mixture was subjected to M analysis without further purification H C CH CH 6 H C ortho meta para 14 1 nly a mixture of isomers containing further DI based impurities could be studied. For this reason, a 1 C M signal assignment and a detailed assignment of the signals of protons 6 and could not be achieved. 1 H M (CDCl ): ~ 8.81 (d; o,m,p ), ~ 8.6 (d; 6 o,m,p ), 8.60 (s; p ), (s; m ), 8.51 ( o ),.8 (t; 26 o ),. (t, 2 m ),.4 (d; 25 o ),.1 (t; 2 o ),.0 (AB spin system, 24 p /28 p and 25 p /2 p ),.295 (d, 26 m ),.21 (s, 24 m ),.18 (28 m ),.10 (d; 28 o ), 2.4 (29 p ), 2.45 (29 m ), 2.0 ppm (29 o ). 5

6 2.4. T2 DI Under an 2 atmosphere, a mixture of DIBr (5 mg, 0.06 mmol), T 2 (5.24 mg, 0.02 mmol), K 2 C (26.12 mg, mmol) and PivH (6.4 mg, 0.06mmol) was dissolved in 1.26 ml of degassed dry toluene in a high pressure vial, followed by addition of Pd 2 dba (0.598 mg, 1 mol %). The vial was placed in a preheated oil bath to 80 C and stirred for 2 h. After cooling to room temperature, the solvent was removed by evaporation and the residue was purified by flash chromatography (dichloromethane/ isohexane = 1:1) to afford 29% (1.2 mg) of T2 DI (2.4.) and 11 % (12 mg) of DI T2 DI (2.5.) as bluish purple solids H M (CDCl ): 8.80 (d,. Hz; ), 8.6 (s; ), 8. (d,. Hz; 6),.28 (dd, 5.2 and 1.1 Hz; 22),.2 (d,.8 Hz; 16),.26 (dd,. and 1.1 Hz; 20),.25 (d,.8 Hz; 1),.06 (dd, 5.2 and. Hz; 21), 4.15 and 4.11 ppm (CH 2 ). 1 C M (CDCl ): 16.1 (1), (14), (12), (11), (18), (2), (15), (19), (), (), 10.5 (6), (16), (9), 12.9 (21), (8), (5), (10), (4), (22), (20), (1), (1), and 44.5 ppm (CH 2 ) DI T2 DI (synthesis see 2.4.) H M (CDCl ): 8.82 (d,.6 Hz; ), 8.8 (s; ), 8.5 (d,.6 Hz; 6),. (d,. Hz; 1),.29 (d,. Hz; 16), 4.16 and 4.1 ppm (CH 2 ). 6

7 1 C M (CDCl ): (1), (14), (12), (11), 140. (15), (2 and 18), (), (), (6), (16), (9), (8), (5), (10), (4), (1), (1), 45.0 ppm (CH 2 ) T2 DI T2 Under an 2 atmosphere, a mixture of DIBr 2 (150 mg, mmol), T 2 (6.18mg, 0.8 mmol), K 2 C (6 mg, mmol) and PivH (15.5 mg, mmol) was dissolved in ml of degassed dry toluene in a high pressure vial, followed by addition of Pd 2 dba (1.9 mg, 1 mol%). The vial was placed in a preheated oil bath to 0 C and stirred for h. After cooling to room temperature, the solvent was removed by evaporation and the residue was purified by flash chromatography (dichloromethane/ isohexane = 1:1) to afford 40% (0.4 mg) of T2 DI T2 (2.6.) and 25 % (40. mg) of T2 DI Br (2..) as bluish solids H M (CDCl ): 8.80 (s; ),.29 (d,. Hz; 16),.28 (dd, 5.1 and 1.2 Hz; 22),.26 (dd,. and 1.1 Hz; 20),.25 (d,. Hz; 1),.06 (dd, 5.1 and. Hz; 21), 4.10 ppm (CH 2 ). 1 C M (CDCl ): (11 14), 140. (18), (15), (2/6), (19), (/), (16), (21), (9/10), (4/8), (22), (1), (1/5), ppm (CH 2 ).

8 2.. T2 DI Br (synthesis see 2.6.) Br 1 H M (CDCl ): 8.98 (s; ), 8.81 (s; ),.29 (dd, 4.9 and 1.1 Hz; 22),.28 (d,.8 Hz; 16),.25 (1 and 20),.06 (dd, 5.2 and. Hz; 21), 4.16 and 4.09 ppm (CH 2 ). 1 C M (CDCl ): (11), (14), (12), (1), (18), 19.9 (2), (15), (), 16. (19), (16), (10), (6), 12.9 (21), 12.2 (9), (8), (22), (4), (20), (1), 12.8 (5), (1), 45. and ppm (CH 2 ) T2 DI pivaloate Under an 2 atmosphere, a mixture of DIBr 2 (90 mg, mmol), PivK (8.44 mg, 0.24 mmol) and T 2 (152 mg, mg) was dissolved in 2 ml of degassed dry DMAc in a high pressure vial, followed by addition of Pd(Ac) 2 (1.01 mg, 5 mol%). The vial then was placed into a preheated oil bath to 80 C and stirred for 0 h. After cooling to room temperature, the mixture was purified by flash chromatography (dichloromethane/ isohexane = 1:1) to afford 16% (15.5 mg) of T2 DI pivaloate as bluish purple solid and 12 % (1 mg) of T2 DI T2 (2.5.) as bluish solid C C(CH ) H M (CDCl ): 8.9 (s; ), 8. (s; ),.28 (dd, 5.0 and 1.2 Hz; 22),.26 (1 and 20),.24 (d,.9 Hz; 16),.05 (dd, 5.0 and. Hz; 21), 4.11 and 4.08 (CH 2 ), 1.52 ppm (25). 1 C M (CDCl ): (2), and (11 and 14), (1), (12), (6), (18), and (2 and 15), (19), 16. (), 129. (16), (), (8), (21), 12.8 (10), (9), (4), (22), (20), (1), (1), (5), and (CH 2 ), 9.51 (24), 2.25 ppm (25). 8

9 2.9. T2 DI DI T2 A chlenk flask was equipped with i(cd) 2 (2.41 mg, mmol), 2,2 bipyridine (8.68 mg, mmol) and 1,5 cyclooctadiene(9.0 mg, mmol) in a glovebox, a dry and degassed mixture of toluene/dmf (5:1, 0.5 ml) was added. The mixture was stirred for 60 min at T. Then T2 DI Br (40 mg, 0.0 mmol) in toluene(0.4 ml) was added and the mixture was stirred overnight at 80 C. Upon cooling to T, 0 ml of aqueous EDTA solution was added to the reaction mixture and stirred for 1 hour. Then it was extracted by CHCl. After removing the solvent, the residue was purified by flash chromotography (dichloromethane/ isohexane = 1:1) to afford the desired product in 5% (1 mg) yield as bluish solid H M (CDCl ): 8.86 (s; ), 8.49 (s; ),. (d,.8 Hz; 16),.0 (dd, 5.0 and 1.1 Hz; 22),.28 (1 and 20),.0 (dd, 5.0 and. Hz; 21), 4.10 and.92 ppm (CH 2 ). 1 C M (CDCl ): 16.0 (1), (14), and (11 and 12), (6), (18), (2), 19.4 (15), (), 16. (19), 11.2 (), (16), (21), (8 or 9), (10), (8 or 9), (4), (22), (20), (1), (1), (5), 45.0 and 44.9 ppm (CH 2 ). 9

10 . Assignment of end group signals and signals of structural defects (DI DI and T2 T2 homocoupling) in the 1 H M spectra of PDIT2 synthesized by DAP (all spectra were measured at 120 C in C 2 D 2 Cl 4 ) Figure I 1 depicts regions from the 1 H M spectrum of a relative low molecularweight PDIT2 showing all signals from end groups observed in the course of this study. These regions allow to identify all these structures by characteristic signals. The following spectra show the same regions from 1 H M spectra of model compounds. Because the chemical shift differences in the DI protons region are small, model compounds based on the structure of DI T2 DI A with different residues 1 in 2 position would be preferred. However, the synthesized model compounds are based on the DI T2 structure B and the DI structure C, respectively. To account for the different substitution in 6 position, the substituent chemical shifts (C) of T2 DI and T2 on protons H 2, H and H were determined from DI T2 DI (Figure I 2) and DI T2 (Figure I ), respectively. A B C With (H 2/4/6/ ) of DI =.9 ppm the following values were determined: replace H 6 by T2 DI: (H 2 ) = 0.01 ppm (H ) = ppm (H ) = ppm replace H 6 by T2: (H 2 ) = 0.02 ppm (H ) = ppm (H ) = ppm replace T2 by T2 DI: (H 2 ) = ppm (H ) = ppm (H ) = ppm. These C value were used for the calculation of end group chemical shifts of DI protons from structure B and structure C based model compounds. Figures I 4 I depict 1 H M spectra of model compounds and give a comparison of experimental or calculated end group chemical shifts with signals observed for PDIT2 synthesized by DAP. Figures I 8 and I 9 depict 1 H M spectra of model compounds for DI DI and T2 T2 homocoupling. 10

11 1 2 Figure I 1. egions from the 1 H M spectrum of PDIT2 recorded in C 2 D 2 Cl 4 at 120 C. ymbol marks 1 C satellite signals and rotation side band ( 20 Hz). ymbol # marks residual DIBr2. Assigned end groups (cf. Figures I 2 to I )) 1 = H (, Fig. I 2) 1 = a b c d e (, Fig. I ) 1 = Br (, Fig. I 4) 1 = C()C(CH ) (, Fig. I 5) 1 = H (, Fig I 6) 1 = H C (, Fig. I ) o characteristic signals of homocouplings (hc) of DI DI (cf. Figure I 8) and T2 T2 (cf. Figure I 9) could be observed. 11

12 12 Figure I 2. 1 H M spectrum of DI T2 DI (regions) recorded in C 2 D 2 Cl 4 at 120 C. ample contains traces of dibenzylideneacetone (#). Hydrogenated DI end group H 2 (model compound) 8.8 ppm H 2 (polymer) 8.8 ppm H (model compound) 8.85 ppm H (polymer) 8.85 ppm H (model compound) 8.8 ppm H (polymer) 8.84 ppm 2 2

13 2 c b a e d Figure I. 1 H M spectrum of DI T2 (regions) recorded in C 2 D 2 Cl 4 at 120 C. ample contains traces of DI and of Tol DI (*). Bithiophene DI end group Calculated from DI T2 DI chemical shifts H 8.85 ppm ppm = 8.89 ppm H (polymer) 8.89 ppm H 8.8 ppm ppm = 8.85 ppm H (polymer) 8.85 ppm Calculated from DI T2 chemical shifts H 8.81 ppm ppm = 8.8 ppm H (polymer) 8.89 ppm H 8.8 ppm ppm = 8.8 ppm H (polymer) 8.85 ppm Bithiophene signals H a H e correspond with those of the polymer. 1

14 14 Figure I 4. 1 H M spectrum of Br DI T2 (regions) recorded in C 2 D 2 Cl 4 at 120 C. Bromine DI end group Calculated replacing T2 by T2 DI H 9.01 ppm ppm = 9.0 ppm H (polymer) 9.0 ppm H 8.86 ppm ppm = 8.88 ppm H (polymer) 8.90 ppm Br Br

15 (CH ) CC Figure I 5. 1 H M spectrum of Piv DI T2 (regions) recorded in C 2 D 2 Cl 4 at 120 C. Pivaloate DI end group (CH ) CC Calculated replacing T2 by T2 DI H 8.42 ppm ppm = 8.44 ppm H (polymer) 8.44 ppm H 8.84 ppm ppm = 8.86 ppm H (polymer) not identified (overlapped) (CH ) C (model compound) 1.59 ppm (CH ) C (polymer) 1.59 ppm 15

16 H 6 Figure I 6. 1 H M spectrum of H DI T2 (regions) recorded in C 2 D 2 Cl 4 at 120 C. H DI end group H Calculated replacing H 6 by T2 DI H 8.6 ppm ppm = 8.42 ppm H (polymer) 8.42 ppm H 8. ppm ppm = 8.81ppm H (polymer) 8.82 ppm H (model compound) ppm H (polymer) ppm 16

17 CH 6 Figure I. 1 H M spectrum of Tol DI (ortho, meta and para isomer) (regions) recorded in C 2 D 2 Cl 4 at 120 C. # marks an impurity. Tolyl DI end group CH Calculated replacing H 6 by T2 DI H (m,p) 8.6 ppm ppm = 8.69 ppm H (m,p) (polymer) 8.69 ppm H (o) 8.5 ppm ppm = 8.59 ppm H (o) (polymer) 8.59 ppm H ~ 8.85 ppm ppm = 8.89ppm H (polymer) not identified (overlapped) CH (p) (model compound) 2.54 ppm CH (p) (polymer) 2.54 ppm CH (m) (model compound) 2.51 ppm CH (m) (polymer) 2.51 ppm CH (o) (model compound) 2.14 ppm CH (o) (polymer) 2.16 ppm 1

18 Figure I C. 1 H M spectrum of T2 DI DI T2 (regions) recorded in C 2 D 2 Cl 4 at DI DI homo coupling Calculated replacing T2 by T2 DI H 8.92 ppm ppm = 8.94 ppm H (polymer) not identified (overlapped) H 8.56 ppm ppm = 8.58 ppm H (polymer) 8.54 ppm CH ppm CH 2 (polymer) not identified (overlapped) 4.01 ppm not observed 18

19 c' b' e' d' n Figure I 9. 1 H M spectrum of PDIT4 (regions) recorded in C 2 D 2 Cl 4 at 120 C. T2 T2 homo coupling c' b' e' d' H (PDIT4) 8.90 ppm H (polymer) not identified (overlapped) H b (PDIT4).26 ppm H (polymer) not observed H c (PDIT4).0 ppm H (polymer) not identified (overlapped) H d (PDIT4).6 ppm H (polymer) not identified (overlapped) H e (PDIT4).4 ppm H (polymer) not identified (overlapped) 19

20 4. ummary of chemical shifts of end groups and homocoupled units of PDIT2 Table I 1. Chemical structures of end groups and homocouplings with chemical shifts in the proton spectra measured in C 2 D 2 Cl 4 at 120 C. ov.: overlapped. 20

21 5. 1 H M spectra of selected PDIT2 samples from Table 1 Figure I 10. Full 1 H M spectrum of entry 19 (0.5 M in toluene at 100 C) in C 2 D 2 Cl 4 at 9 K. Figure I 11. Full 1 H M spectrum of entry 24 (0.5 M in chlorobenzene at 100 C) in C 2 D 2 Cl 4 at 9 K. 21

22 Figure I 12. Full 1 H M spectrum of entry 6 (0.05 M in THF) in C 2 D 2 Cl 4 at 9 K. Figure I 1. Full 1 H M spectrum of entry 28 (0.5 M in toluene in the presence of a phosphine) in C 2 D 2 Cl 4 at 9 K. 22

23 Figure I 14. Full 1 H M spectrum of entry 9 (0.05 M in toluene) in C 2 D 2 Cl 4 at 9 K. 2

24 6. Thermal characterization Endo up -->.KDa M KDa M-16. 1KDa Entry 2 24KDa Entry 21 1KDa Entry 18 5KDa Entry 19 41KDa Entry 24 41KDa Entry 24 5KDa Entry 19 1KDa Entry 18 24KDa Entry 21 1KDa Entry 2 1KDa M-16..KDa M T/ C Figure I 15. DC curves of selected PDIT2 samples measured by DAP. Curves were taken at 10 K/min under nitrogen. tille-1 Endo up --> tille-2 tille- tille- tille-2 tille T/ C Figure I 16. DC curves of PDIT2 samples made by tille coupling. Curves were taken at 10 K/min under nitrogen. 24

25 Table I 2. Collection of thermal data from DC measurements of PDIT2. entry M n /M w / kda T m / C ΔH m / J/g DAP 2 1/ / / / / / tille controls tille-1 16/ tille-2 22/ tille- 2/ T m (DAP) T m (tille) T m ( C) H (DAP) m H (tille) m H m (J.g-1 ) M n,ec / KDa 0 Figure I 1. Melting temperatures T m and enthalpies ΔH m as a function of the number average molar mass. 25

26 . Additional electrical characterization I [ A ] I D I G V G [ V ] Figure I 18. Typical transfer curve of a DAP sample with M n = 1 kda fabricated by standard spin coating. I D ( ma ) V G 0 V V G 10 V V G 20 V V G 0 V V G 40 V V G 50 V V D ( V ) Figure I 19. utput curve of DAP synthesized PDIT2 (entry 18) based FET with M n = 1 kda (off center spin coating). 26

27 8. Additional UV vis spectra norm. absorption 1,6 1,4 1,2 1,0 tille-1 M n / M w 16 / 26 kda DAP M n / M w 15 / 26 kda DAP M n / M w 1 / 90 kda DAP M n / M w 41 / 162 kda tille- M n / M w 2 / 14 kda 0,8 0,6 0,4 0,2 0, wavelength/ nm Figure I 20. UV vis spectroscopy of PDIT2 made by DAP and control batches made by tille as a function of MW in toluene. All the spectra feature similar patterns. Each polymer shows two bands attributed to the π π * transition, the high energy band ( nm) is assigned to excited states more localized on the thiophene units whereas the low energy broad band ( nm) is assigned to excited states with a prevalent HM LUM contribution and classified as charge transfer (CT) states. The main transition at 00 nm and the shoulder at 800 nm have been recently assigned to an aggregate effect 5, while the contribution of the band at 600 nm is negligible or just slightly visible, generally associated to not aggregated molecules. Figure I 15 shows that polymers with M n > 16 kda display totally superimposed spectra, with a neat prevalence of aggregates absorption and in total agreement with the tille reference sample. Differently, in the spectra of polymers with M n 15 kda, a clear contribution of not aggregated polymers is still visible, also reflected by the higher relative intensity of the high energy bands; moreover, comparing the absorption at 600 nm, it clearly appears that the tille sample with M n = 16 kda (black curve) contains an inferior amount of aggregates than the DAP sample with M n = 15 kda (red curve). 2

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