Impact of p-type doping on charge transport in blade-coated small-molecule:polymer blend transistors

Abstract

Blade-coating is a roll-to-roll (R2R) compatible processing technique and has the potential to address the industry’s needs for scalable manufacturing of future organic electronics. Here we investigate the applicability of...

Structural insights into Lewis acid- and F4TCNQ-doped conjugated polymers by solid-state magnetic resonance spectroscopy

“…By analyzing 11 B (spin magnetic moment I = 3/2, and exhibits quadrupolar interaction) MAS NMR spectra of BCF and BCF:P4 bends, we provide further insight into the changes in the local chemical environments of BCF molecules upon addition to the P4 polymer. As seen in Figure 4a, 1D 11 B spectra of neat BCF show a broad quadrupolar lineshape between 45-60 ppm produced by the tricoordinated boron atoms in BCF, and a relatively narrow lineshape near 0 ppm attributed to tetracoordinated boron nuclei in BCF·H 2 O complex. As a result of the increased coordination number of boron, and reduced quadrupolar interactions, the tetracoordinated BCF·H 2 O complex exhibits a relatively narrower signal.…”

“…57,70 Although the neat BCF material was stored in the nitrogen atmosphere of a glovebox, trace amounts of water present (or exposure to ambient during sample preparation for ssNMR studies) were enough to result in the BCF·H 2 O complex, 40 and different types of BCF-water complexes. 42 Upon addition to P4, there is further narrowing of the 11 B peak appearing at 4 ppm, which could be attributable to the BCF molecules embedded into the polymer chains and the hyperfine interactions between BCF-water/BCF.OH  and the P4 polymer radicals. Nevertheless, when a higher concentration of BCF is incorporated into the P4 polymer (1:1 molar ratio), an additional 11 B signal is emerged at ~18 ppm, indicating the formation of additional BCFwater, BCFOH  like or bridged complexes involving two BCF molecules.…”

“…Addition of water molecules promotes the formation of BCFwater and bridged complexes, which influence the doping efficiency of P4:BCF blend. To test this, we carried out 11 B and 1 H MAS NMR experiments as a function of the amount of water added to P4:BCF blend, whereby the 11 B signal at 15-19 ppm is detected with much higher intensity (Figure 4a). Evidently, the 1 H NMR spectra also show the emergence of a water 1 H signal resonating at ~4.5 ppm (Figure 4b), and the 1 H signal integral values associated with aliphatic and aromatic protons (13.2 and 0.5) indicate further signal intensity loss upon addition of water to the P4:BCF blend (Table S1).…”

“…In P4:F4TCNQ, fully doped F4TCNQ molecules lead to strong hyperfine interactions with P4 backbones as revealed by 2D EPR analysis (e.g., charge transfer complexes that may disrupt  stacking), and the undoped/aggregated F4TCNQ molecules (i.e., Please do not adjust margins Please do not adjust margins diamagnetic regions) can be detected by 19 F ssNMR spectroscopy. In the P4:BCF blend, the local boron environments of BCF dopants are characterized by 11 B NMR and the hyperfine structure is characterized by 2D EPR techniques. Furthermore, the results discussed herein elucidate that the BCF doping mechanism does not rely on BCF association (or intercalation) with the conjugated backbone, as it does not require the formation of a charge-transfer complex.…”

The influence of alkyl group regiochemistry and backbone fluorination on the packing and transistor performance of N-cyanoimine functionalised indacenodithiophenes

“…39 In our case we found that the solubility of both dialkyl-diFIDT-di(N(CN)) OSCs was sufficient in chlorobenzene to fabricate transistor devices by blade-coating, a potentially scalable technique for solution based devices. 35,44 Devices were fabricated in a bottomcontact top-gate (BC -TG) configuration, with the active layer deposited onto the substrate at 100 1C, followed by spin coating of the gate dielectric (Cytop TM ) and thermal evaporation of the aluminium gate electrode. The key results are summarised in Table 2.…”