TY - JOUR
T1 - Block Junction-Functionalized All-Conjugated Donor-Acceptor Block Copolymers
AU - Nübling, Fritz
AU - Hopper, Thomas R.
AU - Kuei, Brooke
AU - Komber, Hartmut
AU - Untilova, Viktoriia
AU - Schmidt, Simon B.
AU - Brinkmann, Martin
AU - Gomez, Enrique D.
AU - Bakulin, Artem A.
AU - Sommer, Michael
N1 - Funding Information:
*E-mail: michael.sommer@chemie.tu-chemnitz.de. ORCID Thomas R. Hopper: 0000-0001-5084-1914 Hartmut Komber: 0000-0001-6176-6737 Martin Brinkmann: 0000-0002-2680-1506 Artem A. Bakulin: 0000-0002-3998-2000 Michael Sommer: 0000-0002-2377-5998 Author Contributions The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. Funding The Baden-Württemberg Stiftung gGmbH (research program Clean Tech 2, project CT 2) and the Research Innovation Fund of the University of Freiburg are gratefully acknowledged for funding. B.K. and E.D.G. acknowledge the National Science Foundation for funding under Award DMR-1609417. Notes The authors declare no competing financial interest.
Funding Information:
A.A.B. is a Royal Society University Research Fellow. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Funding Information:
The authors are grateful to M. Hagios, Dr R. Hanselmann, C. Warth, and A. Warmbold (University of Freiburg) for SEC, MALDI-ToF MS, and DSC measurements. Further, Dr P. Shakya Tuladhar (Imperial College London) is greatly acknowledged for OPV device manufacturing. A.A.B. is a Royal Society University Research Fellow. The Advanced Light Source is supported by the Director, Office of Science, Office of Basic Energy Science, of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2019/1/9
Y1 - 2019/1/9
N2 - Junction-functionalized donor-acceptor (D-A) block copolymers (BCPs) enable spatial and electronic control over interfacial charge dynamics in excitonic devices such as solar cells. Here, we present the design, synthesis, morphology, and electronic characterization of block junction-functionalized, all-conjugated, all-crystalline D-A BCPs. Poly(3-hexylthiophene) (P3HT), a single thienylated diketopyrrolopyrrole (Th x DPPTh x , x = 1 or 2) unit, and poly{[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (PNDIT2) are used as donor, interfacial unit, and acceptor, respectively. Almost all C-C coupling steps are accomplished by virtue of C-H activation. Synthesis of the macroreagent H-P3HT-Th x DPPTh x , with x determining its C-H reactivity, is key to the synthesis of various BCPs of type H-P3HT-Th x DPPTh x -block-PNDIT2. Morphology is determined from a combination of calorimetry, transmission electron microscopy (TEM), and thin-film scattering. Block copolymer crystallinity of P3HT and PNDIT2 is reduced, indicating frustrated crystallization. A long period l p is invisible from TEM, but shows up in resonant soft X-ray scattering experiments at a length scale of l p ∼ 60 nm. Photoluminescence of H-P3HT-Th x DPPTh x indicates efficient transfer of the excitation energy to the DPP chain end, but is quenched in BCP films. Transient absorption and pump-push photocurrent spectroscopies reveal geminate recombination (GR) as the main loss channel in as-prepared BCP films independent of junction functionalization. Melt annealing increases GR as a result of the low degree of crystallinity and poorly defined interfaces and additionally changes backbone orientation of PNDIT2 from face-on to edge-on. These morphological effects dominate solar cell performance and cause an insensitivity to the presence of the block junction.
AB - Junction-functionalized donor-acceptor (D-A) block copolymers (BCPs) enable spatial and electronic control over interfacial charge dynamics in excitonic devices such as solar cells. Here, we present the design, synthesis, morphology, and electronic characterization of block junction-functionalized, all-conjugated, all-crystalline D-A BCPs. Poly(3-hexylthiophene) (P3HT), a single thienylated diketopyrrolopyrrole (Th x DPPTh x , x = 1 or 2) unit, and poly{[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (PNDIT2) are used as donor, interfacial unit, and acceptor, respectively. Almost all C-C coupling steps are accomplished by virtue of C-H activation. Synthesis of the macroreagent H-P3HT-Th x DPPTh x , with x determining its C-H reactivity, is key to the synthesis of various BCPs of type H-P3HT-Th x DPPTh x -block-PNDIT2. Morphology is determined from a combination of calorimetry, transmission electron microscopy (TEM), and thin-film scattering. Block copolymer crystallinity of P3HT and PNDIT2 is reduced, indicating frustrated crystallization. A long period l p is invisible from TEM, but shows up in resonant soft X-ray scattering experiments at a length scale of l p ∼ 60 nm. Photoluminescence of H-P3HT-Th x DPPTh x indicates efficient transfer of the excitation energy to the DPP chain end, but is quenched in BCP films. Transient absorption and pump-push photocurrent spectroscopies reveal geminate recombination (GR) as the main loss channel in as-prepared BCP films independent of junction functionalization. Melt annealing increases GR as a result of the low degree of crystallinity and poorly defined interfaces and additionally changes backbone orientation of PNDIT2 from face-on to edge-on. These morphological effects dominate solar cell performance and cause an insensitivity to the presence of the block junction.
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U2 - 10.1021/acsami.8b18608
DO - 10.1021/acsami.8b18608
M3 - Article
C2 - 30523687
AN - SCOPUS:85059394315
VL - 11
SP - 1143
EP - 1155
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
SN - 1944-8244
IS - 1
ER -