A new class of high‐performance n‐type organic thermoelectric materials, self‐doping perylene diimide derivatives with modified side chains, is reported. These materials achieve the highest n‐type thermoelectric performance of solution‐processed organic materials reported to date, with power factors as high as 1.4 μW/mK^2. These results demonstrate that molecular design is a promising strategy for enhancing organic thermoelectric performance

Brunetti, Fulvio G.

Chabinyc, Michael L.

Chang, William B.

Hawker, Craig J.

Ho, Victor

Miller, P. Levi

Patel, Shrayesh N.

Perry, Erin E.

Robb, Maxwell J.

Russ, Boris

Segalman, Rachel A.

Urban, Jeffrey J.

Caltech Authors - Main

Copyright WILEY‐VCH Verlag GmbH & Co. KGaA, 69469 Weinheim, Germany, 2014. 
 
 
 
 
 
 
 
 
 
Supporting Information 
 
 
for Adv. Mater., DOI: 10.1002/adma.201306116 
 
Power Factor Enhancement in Solution-Processed Organic 
n-Type Thermoelectrics Through Molecular Design 
 
Boris Russ, Maxwell J. Robb, Fulvio G. Brunetti, P. Levi 
Miller, Erin E. Perry, Shrayesh N. Patel, Victor Ho, William 
B. Chang, Jeffrey J. Urban, Michael L. Chabinyc,* Craig J. 
Hawker,* and Rachel A. Segalman* 
 Submitted to  
1 
 
Copyright WILEY-VCH Verlag GmbH & Co. KGaA, 69469 Weinheim, Germany, 2014. 
Supporting Information for Adv. Mater., DOI: 10.1002/adma.201306116 
 
 
Power factor enhancement in solution-processed organic n-type thermoelectric molecules 
through side chain design 
 
Author(s), and Corresponding Author(s)* Boris Russⱡ, Maxwell J. Robbⱡ, Fulvio G. Brunetti, 
Levi Miller, Erin E. Perry, Shrayesh Patel, Victor Ho, William B. Chang, Jeffrey J. Urban, 
Michael L. Chabinyc*, Craig J. Hawker*, and Rachel A. Segalman*  
 
 
 
 Materials 
All reagents from commercial sources were used without further purification.  Perylene-
3,4,9,10-tetracarboxylic dianhydride, imidazole, iodomethane, and 2-
(dimethylamino)ethylamine were purchased from Aldrich.  4-(dimethylamino)butylamine 
and 6-(dimethylamino)hexylamine were purchased from Matrix Scientific.  Deuterated 
solvents were obtained from Cambridge Isotope Laboratories, Inc. 
Instrumentation 
1H and 13C NMR spectra were recorded using a Varian 500 or 600 MHz spectrometer with 
the solvent signal as internal reference.  Mass spectrometry was performed on a Micromass 
QTOF2 quadrupole/time-of-flight tandem mass spectrometer (ESI) or a Waters GCT Premier 
time-of-flight mass spectrometer (FD). 
 
General procedure for the synthesis of dimethylamino perylene diimides.  Perylene-
3,4,9,10-tetracarboxylic dianhydride and the alkyl amine (4 eq.) were combined with 
imidazole in a round bottom flask equipped with a stir bar and sealed with a septum.  The 
reaction vessel was purged with argon and subsequently heated with stirring at 130 °C for the 
indicated amount of time.  At the conclusion of the reaction, the vessel was allowed to cool 
to room temperature, the contents were suspended in methanol, and the solid was collected 
 Submitted to  
2 
 
by filtration using a 0.8 μm nylon membrane.  The solid was washed with methanol and 
dried under vacuum to afford the pure product. 
General procedure for the quaternization of dimethylamino perylene diimides.  The 
dimethylamino substituted perylene diimide and iodomethane (4 eq.) were dissolved in 
chloroform in a round bottom flask equipped with a stir bar and condenser and refluxed for 
the indicated amount of time.  At the conclusion of the reaction, the mixture was cooled to 
room temperature and filtered through a 0.8 μm nylon membrane.  The solid was washed 
consecutively with chloroform, diethyl ether, hexane, and ethanol and dried under vacuum to 
afford the pure product. 
 
 
Bis(2-(dimethylamino)ethyl)perylene diimide.  The general procedure was employed using 
perylene-3,4,9,10-tetracarboxylic dianhydride (1.082 g, 2.757 mmol), 2-
(dimethylamino)ethylamine (0.9869 g, 11.20 mmol), and imidazole (14.1 g, 207 mmol) in a 
50 mL round bottom flask.  After 2 h at 130 °C and workup, 1.46 g (99%) of the desired 
product was obtained.  1H NMR (600 MHz, CDCl3): δ 2.37 (s, 12H), 2.70 (t, J = 7.0 Hz, 4H), 
4.37 (t, J = 7.0 Hz, 4H), 8.62 (d, J = 8.0 Hz, 4H), 8.69 (d, J = 7.9 Hz, 4H).  13C NMR (125 
MHz, CDCl3): δ 38.31, 45.69, 56.97, 123.28, 123.46, 126.63, 129.61, 131.66, 134.83, and 
163.64.  MS (FD): m/z [M]+ calcd for [C32H28N4O4]
+, 532.2; found, 532.2. 
 
 
Bis(2-(trimethylammonium)ethyl)perylene diimide diiodide.  The general procedure was 
 Submitted to  
3 
 
employed using bis(2-dimethylamino)ethyl-perylene diimide (0.9048 g, 1.699mmol), 
iodomethane (0.42 mL, 6.8 mmol), and chloroform (50 mL).  After refluxing for 3 h and 
workup, 1.36 g (98%) of the desired product was obtained.  1H NMR (600 MHz, DMSO-d6): 
δ 3.25 (s, 18H), 3.67 (t, J = 7.4 Hz, 4H), 4.51 (t, J = 7.0 Hz, 4H), 8.61 (d, J = 8.1 Hz, 4H), 
8.96 (d, J = 8.1 Hz, 4H).  13C NMR (150 MHz, DMSO-d6): δ 33.70, 52.48, 61.78, 122.41, 
124.79, 125.33, 128.35, 131.00, 133.92, and 162.68.  MS (ESI): m/z [M + Na]+ calculated 
for [C34H34I2N4O4 + Na]
+, 839.0567; found, 839.0552. 
 
 
Bis(4-(dimethylamino)butyl)perylene diimide.  The general procedure was employed 
using perylene-3,4,9,10-tetracarboxylic dianhydride (1.008 g, 2.569 mmol), 4-
(dimethylamino)butylamine (1.203 g, 10.35 mmol), and imidazole (14.4 g, 211 mmol) in a 
50 mL round bottom flask.  After 1.25 h at 130 °C and workup, 1.44 g (95%) of the desired 
product was obtained.  1H NMR (600 MHz, CDCl3): δ 1.59 – 1.68 (m, 4H), 1.75 – 1.84 (m, 
4H), 2.24 (s, 12H), 2.35 (t, J = 7.6 Hz, 4H), 4.23 (t, J = 7.7 Hz, 4H), 8.49 (d, J = 8.0 Hz, 4H), 
8.59 (d, J = 7.9 Hz, 4H).  13C NMR (125 MHz, CDCl3): δ 25.28, 26.19, 40.57, 45.53, 59.49, 
123.17, 123.36, 126.43, 129.38, 131.45, 134.62, and 163.42.  MS (FD): m/z [M]+ calcd for 
[C36H36N4O4]
+, 588.3; found, 588.3. 
 
 
Bis(4-(trimethylammonium)butyl)perylene diimide diiodide.  The general procedure was 
 Submitted to  
4 
 
employed using bis(4-dimethylamino)butyl-perylene diimide (0.7813 g, 1.327 mmol), 
iodomethane (0.35 mL, 5.6 mmol), and chloroform (40 mL).  After refluxing for 2 h and 
workup, 1.14 g (98%) of the desired product was obtained.  1H NMR (600 MHz, DMSO-d6): 
δ 1.71 (p, J = 7.3 Hz, 4H), 1.79 – 1.88 (m, 4H), 3.08 (s, 18H), 3.36 – 3.42 (m, 4H), 4.12 (t, J 
= 7.4 Hz, 4H), 8.43 (d, J = 8.0 Hz, 4H), 8.74 (d, J = 7.9 Hz, 4H).  13C NMR (150 MHz, 
DMSO-d6): δ 19.87, 24.44, 52.35, 64.98, 122.73, 124.21, 125.42, 128.30, 130.95, 133.76, 
and 162.77.  MS (ESI): m/z [M + Na]+ calcd for [C38H42I2N4O4 + Na]
+, 895.1193; found, 
895.1182. 
 
 
Bis(6-(dimethylamino)hexyl)perylene diimide.  The general procedure was employed 
using perylene-3,4,9,10-tetracarboxylic dianhydride (1.042 g, 2.656 mmol), 6-
(dimethylamino)hexylamine (1.522 g, 10.55 mmol), and imidazole (17.1 g, 251 mmol) in a 
50 mL round bottom flask.  After 1.5 h at 130 °C and workup, 1.64 g (96%) of the desired 
product was obtained.  1H NMR (600 MHz, CDCl3): δ 1.37 – 1.55 (m, 12H), 1.77 (p, J = 7.8 
Hz, 4H), 2.21 (s, 12H), 2.26 (t, J = 7.5 Hz, 4H), 4.18 (t, J = 7.4 Hz, 4H), 8.41 (d, J = 8.0 Hz, 
4H), 8.54 (d, J = 7.9 Hz, 4H).  13C NMR (125 MHz, CDCl3): δ 27.30, 27.40, 27.83, 28.12, 
40.71, 45.62, 59.97, 122.48, 122.96, 125.40, 128.64, 130.64, 133.52, and 162.76.  MS (FD): 
m/z [M]+ calcd for [C40H44N4O4]
+, 644.3; found, 644.3. 
 
 Submitted to  
5 
 
 
Bis(6-(trimethylammonium)hexyl)perylene diimide diiodide.  The general procedure was 
employed using bis(6-dimethylamino)hexyl-perylene diimide (0.9086 g, 1.409 mmol), 
iodomethane (0.35 mL, 5.6 mmol), and chloroform (50 mL).  After refluxing for 2 h and 
workup, 1.28 g (98%) of the desired product was obtained.  1H NMR (600 MHz, DMSO-d6): 
δ 1.36 (p, J = 7.2 Hz, 4H), 1.45 (p, J = 7.2 Hz, 4H), 1.67-1.75 (m, 8H), 3.04 (s, 18H), 3.26-
3.31 (m, 4H), 4.08 (t, J = 7.5 Hz, 4H), 8.50 (d, J = 7.9 Hz, 4H), 8.83 (d, J = 7.9 Hz, 4H).  13C 
NMR (125 MHz, DMSO-d6): δ 22.08, 25.68, 26.18, 27.32, 52.14, 65.28, 121.75, 123.62, 
124.46, 127.54, 130.19, 133.04, and 162.23.  MS (ESI): m/z [M - I]+ calcd for 
[C42H50IN4O4]
+, 801.2871; found, 801.2861. 
 
 
Electron paramagnetic resonance (EPR) analysis 
EPR samples of ethyl, butyl, and hexyl PDI were prepared by dropcasting solutions of each 
onto 2 cm by 2 cm quartz microscope cover slides. Each solution was approximately 1 
mg/mL solution of PDI/deionized water. These samples were dried at 75 oC for 45 minutes. 
Upon drying, they were transferred into a dry glovebox with a nitrogen atmosphere. Inside the 
glovebox, the samples were cleaved into approximately 3 mm-wide pieces; the most uniform 
and rectangular pieces were saved as the final samples. Before measurement, samples were 
baked for 20 minutes at 120 oC inside the glovebox and then inserted into 4 mm-diameter 
quartz EPR tubes. These tubes were sealed with plastic caps and Teflon tape inside the 
glovebox. They were then transferred outside of the glovebox and their EPR spectra were 
measured within two hours. 
 Submitted to  
6 
 
Spin concentrations were determined by comparing the integrated signal intensity of a sample 
with the integrated signal intensity of a standard of known concentration. In this experiment, 
the spin concentration calculations were complicated by the variation in film thickness that 
resulted from the dropcasting. The thickness of each sample was measured using profilometry. 
The film was scraped off in three locations down to the substrate and the average difference in 
thickness across these sites was quoted as the average thickness of the dropcasted film.  To 
calculate the spin concentrations, we measured the samples after a 20 minute, 120 C bake and 
compared the normalized, integrated intensity of the samples to the normalized, integrated 
intensity of a standard material. 2,2-diphenyl-1-picrylhydrazyl (DPPH) was used as the 
standard sample and a calibrator for determining the g-factor of each material. Error in 
comparing the spin concentration stemmed from uncertainty with regards to the concentration 
of the standard and the error in measuring the length, width, and thickness of each sample. 
Raw EPR signatures are shown in Figure S1.  
 
 Submitted to  
7 
 
 
Figure S1: EPR signatures for PDI-1, PDI-2, and PDI-3 in comparison to a reference sample 
of DPPH. 
 
 
 Submitted to  
8 
 
 
Figure S2: AFM images of thin films of PDI-1. Both the amplitude and the phase images are 
shown. Domains in these thin films appear to be hundreds of nanometers to microns in size.  
 


Power Factor Enhancement in Solution‐Processed Organic n‐Type Thermoelectrics Through Molecular Design

https://authors.library.caltech.edu/86799/2/adma201306116-sup-0001-s1.pdf

Power Factor Enhancement in Solution‐Processed Organic n‐Type Thermoelectrics Through Molecular Design

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