Determinant Role of Solution‐State Supramolecular Assembly in Molecular Orientation of Conjugated Polymer Films

Abstract

The solid‐state molecular orientation of conjugated polymers is of vital importance for their charge transport properties, where the edge‐on orientation with π‐stacking direction parallel to the surface is generally preferable to achieving high‐mobility planar field‐effect transistors. However, so far, little is known about the origin of packing‐orientation formation in thin films. Here, it is shown that the solution‐state supramolecular structure of widely studied PffBT4T‐based polymers can be reversibly tuned between 1D worm‐like and 2D lamellar structures for the same polymer/solvent system through solution temperature. Such dimensionality in solution determines the solid‐state packing orientation of the polymer chains, where edge‐on and face‐on textures are generated from solutions with 1D and 2D structures, respectively. More importantly, the transition temperature of solution‐state supramolecular dimensionality is in excellent agreement with that of solid‐state packing orientation. These experimental observations unambiguously demonstrate the predominant roles of solution‐state supramolecular assembly in solid‐state molecular orientation, which is further verified using different molecular weight batches and other two representative polymers. The findings provide new insights into the growth mechanism of polymer semiconductors during transistor fabrication, and open prospective pathways for boosting device performance of solution‐processable plastic electronics.

Side-Chain-Assisted Transition of Conjugated Polymers from a Semiconductor to Conductor and Comparison of Their NO2 Sensing Characteristics

“…The distinct electrical properties of PTQ-TEG , compared to PTQ-T, could be due to the contribution of EG-based side chains because both CPs have the same conjugated framework. To ascertain the effect of the EG-based side chain on the electrical properties of PTQ-TEG , the film morphologies and chain assembly features of both CPs were characterized using AFM and 2D-GIXRD, respectively, because the electrical properties of CPs are known to be sensitively affected by the degree of chain aggregation and assembly [ 49 , 50 ]. As shown in Figure 3 a,b, both CPs exhibited featureless smooth surfaces with root-mean-square (RMS) roughness values of 0.478 nm and 0.355 nm for PTQ-T and PTQ-TEG , respectively.…”

Structural control of charge transport in polymer monolayer transistors by a thermodynamically assisted dip-coating strategy

“…1a). 25,27,33 Scheme 1 Schematic illustration of charge transport in organic semiconducting multilayer (left) and monolayer (right) FETs with threedimensional (3D) and 2D transport.…”

“…1a). 25,27,33 Fig. 1a shows the UV-vis-NIR absorption spectra of PffBT4T-2DT in a chloroform solution at different temperatures, and it is clear that the elevated temperature severely affects the aggregation behavior of PffBT4T-2DT in solution.…”

Non-Conjugated Copoly(Arylene Ether Ketone) for the Current-Collecting System of a Solar Cell with Indium Tin Oxide Electrode

“…This idea is the basis of the strategy of “control of the supramolecular structure in the solution state” to control the electrophysical and optical properties of thin films [ 28 , 29 ]. In this case, the strength of the polymer–solvent interaction can be controlled by changing the concentration of the polymer in the solution or the temperature of the solution [ 30 ]. Films were made by centrifugation from a polymer solution.…”