Fast-Coating Process Based on Elongated Rodlike Preaggregate for Highly Oriented Thin Film of Donor–Acceptor π-Conjugated Polymer

Abstract

A fast meniscus-guided coating for ultrahighly oriented thin films of a typical donor–acceptor π-conjugated polymer, poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno[3,2-b]thiophene)](PDPP-DTT) was realized. A coating speed higher than 100 mm/s, which was regarded as a Landau–Levich regime, was applicable. The 2D order parameter (S 2) of the thin films changed by selecting the solvent and adjusting the initial concentration of the solution, and the large elongated rodlike preaggregates formed particularly in chlorobenzene contributed to the high orientation in the solid film state, resulting in the highest value of S 2 = 0.87. Focused on the PDPP-DTT preaggregate formation in the solution, the SAXS analysis was carried out to investigate the shape and size of the preaggregates. The mechanism of the molecular orientation was discussed by taking the preaggregates and the solution flow under the coating process into account.

Tailoring the Morphology of a Diketopyrrolopyrrole‐based Polymer as Films or Wires for High‐Performance OFETs using Solution Shearing

“…As the absorbance values recorded from these measurements were very low, the data obtained for both film and wire samples have been normalized with respect to the maximum absorption peak of the respective measurements. It is commonly observed that DPP‐DTT exhibits a dual‐band absorption [ 18,27,31 ] and we clearly see an increased red shift in the absorption for the wires which can be attributed to the strong intermolecular coupling. [ 28,29,32 ] The two absorption peaks between 725 and 900 nm correspond to the π‐π* transitions of 0–1 and 0‐0, respectively.…”

“…[ 28,29,32 ] The two absorption peaks between 725 and 900 nm correspond to the π‐π* transitions of 0–1 and 0‐0, respectively. [ 13,31 ] A clear redshift of these peaks to a greater extent of 50 nm is evident as shown more clearly in Figure S9, Supporting Information.…”

Non-covalent planarizing interactions yield highly ordered and thermotropic liquid crystalline conjugated polymers

“…In contrast, the annealed film demonstrates a high birefringence, indicating a notable increase in the number and/or size of crystallites. 67–69 Furthermore, the CPOM images of the annealed film (Fig. 6b and Fig.…”

The role of solvents in the microstructure and charge transport of semiconducting polymer films prepared at the air–liquid interface

“…Aggregation is quite often reported in donor-acceptor SCPs. [49][50][51][52] Fig. 6(a) shows the DR of the P(NDI2OD-T2) films processed with CF and the CF:CB blend.…”