Hybrid 3D printing is a new method for producing soft electronics that combines direct ink writing of conductive and dielectric elastomeric materials with automated pick-and-place of surface mount electronic components within an integrated additive manufacturing platform. Using this approach, insulating matrix and conductive electrode inks are directly printed in specific layouts. Passive and active electrical components are then integrated to produce the desired electronic circuitry by using an empty nozzle (in vacuum-on mode) to pick up individual components, place them onto the substrate, and then deposit them (in vacuum-off mode) in the desired location. The components are then interconnected via printed conductive traces to yield soft electronic devices that may find potential application in wearable electronics, soft robotics, and biomedical devices.

This study establishes an approach to 3D print Li‐ion battery electrolytes with controlled porosity using a dry phase inversion method. This ink formulation utilizes poly(vinyldene fluoride) in a mixture of N‐methyl‐2‐pyrrolidone (good solvent) and glycerol (weak nonsolvent) to generate porosity during a simple drying step. When a nanosized Al2O3 filler is included in the ink, uniform sub‐micrometer pore formation is attained. In other words, no additional processing steps such as coagulation baths, stretching, or etching are required for full functionality of the electrolyte, which makes it a viable candidate to enable completely additively manufactured Li‐ion batteries. Compared to commercial polyolefin separators, these electrolytes demonstrate comparable high rate electrochemical performance (e.g., 5 C), but possess better wetting characteristics and enhanced thermal stability. Additionally, this dry phase inversion method can be extended to printable composite electrodes, yielding enhanced flexibility and electrochemical performance over electrodes prepared with only good solvent. Finally, sequentially printing this electrolyte ink over a composite electrode via a direct write extrusion technique has been demonstrated while maintaining expected functionality in both layers. These ink formulations are an enabling step toward completely printed batteries and can allow direct integration of a flexible power source in restricted device areas or on nonplanar surfaces.

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We report on a systematic study of solvent and polymer matrix effects on the phase segregation behavior of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) blends incorporated into two different amorphous polymer matrices, poly (a-methyl styrene) and poly (triarylamine), and using two solvents, chlorobenzene and tetralin. Optical microscopy, X-ray diffraction analyses, and optical absorption measurements are used to evaluate the film morphology, crystallinity, and optical density, respectively. These analyses are correlated with the extent of vertical segregation of TIPS-pentacene, as observed for the blended films by depth-profile XPS analyses. The microstructure and vertical phase segregation of TIPS-pentacene in blend films are found to be strongly influenced by the choice of solvent. Tetralin, a solvent with a high boiling temperature, was found to be more desirable for achieving distinct phase segregation/crystallization of TIPS-pentacene in blend films and best performance in OFETs with a dual-gate geometry. The electrical properties of top and bottom channels were consistent with the morphological characterization and OFETs processed from tetralin showed higher mobility values than those from chlorobenzene. Further modification of the annealing conditions in the TIPS-pentacene/PTAA/tetralin ternary system led to top-gate OFETs with mobility values up to 2.82 cm 2 /Vs.

A universal approach to develop 3D printable, free-standing, and current collector-embedded electrode inks has been established.