Electron Mobility of Diketopyrrolopyrrole Copolymers Is Robust against Homocoupling Defects

Author(s):Show less -

Wang, Qian ^[1] ; Lenjani, Shayan Vazirieh ^[1] ; Dolynchuk, Oleksandr ^[2] ; Scaccabarozzi, Alberto D. ^[3] ; Komber, Hartmut ^[4] ; Guo, Yuejie ^[5] ; Gunther, Florian ^[6] ; Gemming, Sibylle ^[5] ; Magerle, Robert ^[5] ; Caironi, Mario ^[3] ; Sommer, Michael ^[1]

Affiliation

^[1] Tech Univ Chemnitz, Inst Chem, D-09111 Chemnitz - Germany

^[2] Martin Luther Univ Halle Wittenberg, Expt Polymer Phys, D-06120 Halle - Germany

^[3] Ist Italiano Tecnol, Ctr Nano Sci & Technol PoliMi, I-20133 Milan - Italy

^[4] Leibniz Inst Polymerforsch Dresden EV, D-01069 Dresden - Germany

^[5] Tech Univ Chemnitz, Inst Phys, D-09126 Chemnitz - Germany

^[6] Univ Sao Paulo, Inst Fis Sao Carlos, BR-13660970 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: CHEMISTRY OF MATERIALS; v. 33, n. 2, p. 668-677, JAN 26 2021.
• Web of Science Citations: 0

Abstract

Structural defects in semiconducting conjugated polymers are usually suspected to deteriorate their properties and device performance and therefore complicate batch-to-batch reproducibility. This study investigates homocoupling (hc) defects in copolymers made from dithiazolyldiketopyrrolopyrrole (TzDPPTz) and tetrafluorobenzene (F4) by direct arylation polycondensation (DAP). Hc defects are quantified by H-1 NMR spectroscopy with good accuracy, and the effect of several reaction parameters on the TzDPPTz hc content in the resulting copolymers PTzDPPTzF4 is investigated in detail. A range of polymers with hc contents between 0.6 and 12.4% is used for a detailed structure-function relationship study. Experimentally, it is observed that TzDPPTz hc defects cause bathochromically shifted absorption spectra, decrease photoluminescence, and lower the lowest unoccupied molecular orbital (LUMO) energy level. Thin film morphology, nanostructure, and electron mobility probed by field-effect devices is marginally or not affected. The latter result is explained by theoretical calculations that suggest a localization of the highest occupied molecular orbital on the hc defect, but not that of the LUMO, the latter being relevant for electron transport. Thus, under these conditions, the hc content is not limiting device performance, which makes PTzDPPTzF4 a robust electron-transporting copolymer. These results are promising in the context of batch-to-batch reproducibility and further guide efforts toward a more detailed understanding of hc-function relationships. (AU)

• FAPESP's process: 18/15670-5 - Novel Semiconducting Materials based on PDMS and DPP for Flexible and Stretchable Electronics: Fabrication, Analysis and Applications in Organic Devices
• Grantee: Florian Steffen Günther
• Support Opportunities: Scholarships in Brazil - Post-Doctoral