A conjugated‐polymer‐based n‐type yarn for thermoelectric textiles is presented. Thermoelectric textile devices are intriguing power sources for wearable electronic devices. The use of yarns comprising conjugated polymers is desirable because of their potentially superior mechanical properties compared to other thermoelectric materials. While several examples of p‐type conducting yarns exist, there is a lack of polymer‐based n‐type yarns. Here, a regenerated cellulose yarn is spray‐coated with an n‐type conducting‐polymer‐based ink composed of poly(benzimidazobenzophenanthroline) (BBL) and poly(ethyleneimine) (PEI). The n‐type yarns display a bulk electrical conductivity of 8 × 10−3 S cm−1 and Seebeck coefficient of −79 µV K−1. A promising level of air‐stability for at least 13 days can be achieved by applying an additional thermoplastic elastomer coating. A prototype in‐plane thermoelectric textile, produced with the developed n‐type yarns and p‐type yarns, composed of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)‐coated regenerated cellulose, displays a stable device performance in air for at least 4 days with an open‐circuit voltage per temperature difference of 1 mV °C−1. Evidently, polymer‐based n‐type yarns are a viable component for the construction of thermoelectric textile devices.

Organic electrochemical transistors (OECTs) are a rapidly advancing technology that plays a crucial role in developing next-generation bioelectronic devices. Recent advances in p-type/n-type organic mixed ionic-electronic conductors (OMIECs) have enabled...

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Water-based conductive inks are vital for sustainable manufacturing and widespread adoption of organic electronic devices. Traditional methods to produce waterborne conductive polymers involve modifying their backbone with hydrophilic side chains or using surfactants to form and stabilize aqueous nanoparticle dispersions. However, these chemical approaches are not always feasible and can lead to poor material/device performance. Here, we demonstrate that ground-state electron transfer (GSET) between donor and acceptor polymers allows the processing of water-insoluble polymers from aqueous solutions. This mutual electrical doping enables solid films with 10,000× higher electrical conductivities than pristine polymers, low work function, and excellent thermal/solvent stability. These waterborne conductive films have technological implications for realizing high-performance organic solar cells, with efficiency and stability superior to conventional metal oxide electron transport layers, and organic electrochemical neurons with biorealistic firing frequency. Our findings demonstrate that GSET offers a new avenue to develop water-based conductive inks for a wide range of potential applications in organic electronics.