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Abstract Conjugated polyelectrolytes (CPEs) exhibit a strong interplay between ionic and electronic properties, enabling tunable photophysical properties and charge transport dynamics. Polyelectrolyte complexation represents a versatile self‐assembly strategy to control the properties of CPEs by forming dense phases with varying optoelectronic and mechanical characteristics. This study focuses on ionically assembled complexes comprising oppositely charged self‐doped CPE (CPE‐K) and bottlebrush polyelectrolyte (BPE). It is demonstrated that subtle adjustments in the composition of CPE‐K:BPE blends enables tuning of photophysical and viscoelastic properties. It is observed that increasing the CPE‐K:BPE monomeric ratio from 1:1 to 1:3 in the initial solution for complexation induces a significant bathochromic shift in the maximum photoluminescence intensity of the dense phase, from 1.8 to 1.4 eV. Additionally, a higher BPE content enhances the softness and adhesion of the solid complex, while maintaining yield‐stress behavior and cyclability of the dense phase. The ability to electrochemically and statically dope the CPE‐K–BPE complex, effectively modulating its charge transport and optoelectronic properties is also demonstrated. This work underscores the potential of these complex‐fluid phases for developing soft, adhesive, and elastic mixed ionic‐electronic conductors with tunable properties for functional applications and 3D‐printing. 

Abstract Since doped polymers require a charge‐neutralizing counter‐ion to maintain charge neutrality, tailored and high degrees of doping in organic semiconductors requires an understanding of the coupling between ionic and electronic carrier motion. A method of counter‐ion exchange is utilized using the polymeric semiconductor poly[2,5‐bis(3‐tetradecylthiophen‐2‐yl)thieno[3,2‐b]thiophene] ‐C₁₄to deconvolute the effects of ionic/polaronic interactions with the electrical properties of doped semiconducting polymers. In particular, exchanging the counter‐ions of the dopant nitrosonium hexafluorophosphate enables investigation into the role of counter‐ion size from 5.2 to 8.2 Å in diameter. The orientational order of the polymeric crystallites is not affected with this exchange process while effectively modifying the counter‐ion distance to the charge carrier. Doped films have electrical conductivities of 320 S cm⁻¹and are not sensitive to an increased ion‐polaron distance. It is posited that other factors dominate the electrical properties at a device scale, such as the morphology and presence of domain boundaries. Interestingly, the temperature stability of the doped film can be drastically improved with the use of counter‐ions containing less labile bonds. This platform serves as a unique way to retain the morphology of polymeric thin films while studying charge interactions at the local scale. 

Abstract In organic mixed ionic–electronic conductors (OMIECs), it is critical to understand the motion of ions in the electrolyte and OMIEC. Generally, the focus is on the movement of net charge during gating, and the motion of neutral anion–cation pairs is seldom considered. Uptake of mobile ion pairs by the semiconductor before electrochemical gating (passive uptake) can be advantageous as this can improve device speed, and both ions can participate in charge compensation during gating. Here, such passive ion pair uptake in high‐speed solid‐state devices is demonstrated using an ion gel electrolyte. This is compared to a polymerized ionic liquid (PIL) electrolyte to understand how ion pair uptake affects device characteristics. Using X‐ray photoelectron spectroscopy, the passive uptake of ion pairs from the ion gel into the OMIEC is detected, whereas no uptake is observed with a PIL electrolyte. This is corroborated by X‐ray scattering, which reveals morphological changes to the OMIEC from the uptake of ion pairs. With in situ Raman, a reorganization of both anions and cations is then observed during gating. Finally, the speed and retention of OMIEC‐based neuromorphic devices are tuned by controlling the freedom of charge motion in the electrolyte.