A Single Droplet‐Printed Double‐Side Universal Soft Electronic Platform for Highly Integrated Stretchable Hybrid Electronics

Abstract

Soft features in electronic devices have provided an opportunity of gleaning a wide spectrum of intimate biosignals. Lack of data processing tools in a soft form, however, proclaims the need of bulky wires or low‐performance near‐field communication externally linked to a “rigid” processor board, thus tarnishing the true meaning of “soft” electronics. Furthermore, although of rising interest in stretchable hybrid electronics, lack of consideration in multilayer, miniaturized design and system‐level data computing limits their practical use. The results presented here form the basis of fully printable, system‐level soft electronics for practical data processing and computing with advanced capabilities of universal circuit design and multilayer device integration into a single platform. Single droplet printing‐based integration of rigid islands and core–shell vertical interconnect access (via) into a common soft matrix with a symmetric arrangement leads to a double‐side universal soft electronic platform that features site‐selective, simultaneous double‐side strain isolation, and vertical interconnection, respectively. Systematic studies of island‐morphology engineering, surface‐strain mapping, and electrical analysis of the platform propose optimized designs. Commensurate with the universal layout, a complete example of double‐side integrated, stretchable 1 MHz binary decoders comprised of 36 logic gates interacting with 9 vias is demonstrated by printing‐based, double‐side electronic functionalization.

Materials and Structures toward Soft Electronics

“…First, the current active component density of soft electronics is low in comparison with state‐of‐the‐art rigid electronics driven by Moore's law. Enabling technologies for creating vertical interconnect access (VIA) for 3D integration and for assembling high‐density electronic components such as bare dies on soft substrates will need to be developed . Second, even though there have been a lot of approaches for minimizing the strain level in soft electronics, they are still premature for daily use due to the delicate and fragile nature of the components.…”

Multiscale Soft–Hard Interface Design for Flexible Hybrid Electronics

“…Enabling technologies for assembling high-density and multifunctional electronic components is required. [241,242] Third, even though there have been many approaches for enhancing soft-hard interface bonding, it is still challenging to use them in harsh environments. Few FHEs to date could last through machine washing processes or long-term repeated use.…”

Distortion‐Free Stretchable Light‐Emitting Diodes via Imperceptible Microwrinkles

“…One of the representative structural designs is connecting the LEDs placed at the stress‐free island areas to stretchable interconnects, so‐called island‐bridge structure. Metallic‐based electrodes using serpentine structure, [ 8 ] metallic nanoparticles embedded in a soft matrix, [ 9 ] or vertically wavy structure [ 10 ] were reported as candidates for stretchable interconnects. However, because the stretchable interconnect that occupies the area between the adjacent islands determines the stretchability of the system, insufficient space for the interconnects results in reduced stretchability due to the highly concentrated strain.…”