The development of organic electrochemical transistors (OECTs) critically depends on the design and characterization of mixed-conducting, high-performance conjugated polymers (CPs) as channel materials, particularly for n-type OECTs. In this study, we present a novel strategy to enhance the OECT performance of a semiconducting polymer film via a postdeposition ester pyrolysis of thermally cleavable side chains, thus facilitating ion incorporation and transport within the bulk. Our approach relies on the synthesis of a high glass-transition, rigid-rod polymer, able to withstand the pyrolysis temperature without deformation and maintain the voids formed from the pyrolysis reaction which removes the thermally cleavable ester side chains. After side-chain cleavage, the resulting film exhibits increased porosity, hydrophilicity, and crystallinity. By creating bulk porosity in thin films via this approach, ion diffusion is enhanced, resulting in a superior μC* figure of merit up to 158.85 F cm–1 V–1 s–1, and a corresponding increase in normalized transconductance (31.67 S cm–1). In addition, the device switching speed and long-term stability are also observed to increase, further demonstrating the benefit of nanoscale porosity for mixed conductivity semiconductors. ... Read more

Bioelectronics is a rapidly evolving interdisciplinary field that integrates principles of electrical engineering, materials science, and biology to develop electronic interfaces capable of recording and stimulating biological activity of the human body. The conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has emerged as a key bioelectronic material due to its unique properties, processing versatility, and biocompatibility. This work provides an overview of PEDOT:PSS-based bioelectronic interfaces and their growing potential in clinical applications. The historical development of PEDOT:PSS is first traced, highlighting its rise as one of the most successful materials in organic bioelectronics. The fundamental properties that make PEDOT:PSS particularly well-suited for bioelectronic interfaces are then examined, with a focus on how these properties can be precisely tuned through advanced processing and fabrication techniques. Both well-established micropatterned interfaces and the latest advancements in multidimensional hydrogel-based structures are discussed. Finally, cutting-edge clinical applications of bioelectronic systems that incorporate PEDOT:PSS are discussed, underscoring their potential in next-generation medical technologies. Overall, this work presents a balanced and forward-looking perspective that connects the evolution of PEDOT:PSS to its emerging role in clinically translatable bioelectronic systems. ... Read more

Driving by the increased demand for hermetic packaging in the more than Moore (MtM) roadmap, a Cu nanoparticle sintering-enabled hermetic sealing solution was developed with a small-size sealing ring. The developed technology simplifies microfabrication and requires less surface roughness using a sinterable Cu nanoparticle paste. A 50μm size Cu paste sealing ring was achieved using a lithography patterned photoresist as a stencil mask. A groove-structured chip was used to amplify localized stress. The Cu nanoparticle paste was fully sintered at 300 °C under pressure ranging from 10 to 40 MPa resulting in a robust bonding with a maximum shear strength of 280 MPa and implementing hermetic packaging. The deflection of the Si diaphragms estimated a vacuum level of 7 kPa. Vacuum sealing was maintained for over six months, and the lowest leak rate was calculated as 8.4× 10 ^-13Pa·m ³/s. The developed technology that comprises small-size patterning and pressure-assisted sintering offers the potential for a simple, cost-effective, but robust solution for hermetic packaging. ... Read more