Wrap-like transfer printing for three-dimensional curvy electronics

Abstract

Three-dimensional (3D) curvy electronics has wide-ranging application in biomedical health care, soft machine, and high-density curved imager. Limited by material properties, complex procedures, and coverage ability of existing fabrication techniques, the development of high-performance 3D curvy electronics remains challenging. Here, we propose an automated wrap-like transfer printing prototype for fabricating 3D curvy electronics. Assisted by a gentle and uniform pressure field, the prefabricated planar circuits on the petal-like stamp are integrated onto the target surface intactly with full coverage. The driving pressure for the wrapping is provided by the strain recovery of a prestrained elastic film triggered by the air pressure control. The wrapping configuration and strain distribution of the stamp are simulated by finite element analysis, and the pattern and thickness of the stamps are optimized. Demonstration of this strategy including spherical meander antenna, spherical light-emitting diode array, and spherical solar cell array illustrates its feasibility in the development of complex 3D curvy electronics.

Electrohydrodynamic Jet Morphology Modulation for Highly Spatially Controllable Piezoelectric Nanowire Deposition

“…These printed PZT nanowires can be used not only as a piezoelectric functional material but also as a mask for etching metals to fabricate metal nanoelectrodes (Figure S7), enabling the fabrication of highly integrated microcircuits as well as wire interconnection of 3D stacked electronic devices. Until now, some conformal manufacturing methods on the curved surface, like transfer printing, laser direct writing, conformal inkjet printing, kirigami/origami assembling, and holographic lithography, have been proposed to prepare deformable sensors or 3D functional circuits to facilitate compatibility with complex curved surfaces like soft, 3D biological tissue or soft robotics. − As part of the powerful conformal printing, the electrohydrodynamic jet modulation techniques proposed in this article can cost-effectively print complex patterns directly onto curvilinear surfaces with higher resolution than inkjet printing and hold great potential as an attractive alternative for manufacturing conformal devices with higher performance and integration. Moreover, these high-controllability PZT patterns can be transferred onto a stretchable substrate using a sacrificial layer-assisted method as shown in Figure S8, showing high application potential in flexible electronics and deformable piezoelectric devices…”

Mechanically-Guided 3D Assembly for Architected Flexible Electronics

“…Flexible 3D antennas with various structural configurations were developed through mechanically-guided methods. ,,,,, For example, a 3D spiral inductor for near-field communication (NFC) was fabricated, exhibiting significantly enhanced Q factors and almost doubled voltages over a wide range of working angles (i.e., from 0° to 50°) when compared to devices in planar forms (Figure a) . Flexible hemispherical ESAs were also manufactured to offer ideal communication performances (Figure b) .…”

Switchable Adhesive Based on Shape Memory Polymer with Micropillars of Different Heights for Laser-Driven Noncontact Transfer Printing

“…Transfer printing, as an advanced heterogeneous material integration technique, − has greatly attracted the interest of academia and industry due to its great potential in deterministic assembly with applications in developing unconventional electronic systems, such as curved electronics, − micro light-emitting diode display, − and flexible electronics. − The typical process of transfer printing is to utilize a switchable adhesive (i.e., stamp) to pick up electronic components (i.e., inks) of different shapes or materials from their fabricated substrate (i.e., donor) and print them onto the target substrate (i.e., receiver). The ability of adhesion switch in a rapid and repeatable manner enabled by the switchable adhesive from a strong state for pick-up to a weak state for printing is essential to the success of transfer printing.…”