Session: Government Agency Student Posters

Paper Number: 173186

Conformal Additive Stamp Printing for Manufacturing Three-Dimensional Curvy Electronics 

Introduction: The realization of curvilinear, conformable, and stretchable electronics is essential for next-generation bio-integrated and wearable devices, yet remains constrained by the limitations of planar microfabrication technologies. This work presents a universal manufacturing strategy termed conformal additive stamp (CAS) printing, a technique that enables the direct, high-fidelity transfer of prefabricated electronic devices onto arbitrary 3D curvy surfaces. CAS printing employs a pneumatically inflated elastomeric balloon stamp to pick up devices with high surface conformity and print them onto complex geometries without inducing mechanical damage or significant strain in active components. This method allows for the seamless integration of silicon-based optoelectronic devices, sensors, and energy systems onto non-developable surfaces, surpassing the geometric constraints of conventional wafer-based processes.

 

Contribution: The CAS printing method offers a robust, scalable, and material-agnostic route for producing high-performance curvy electronics. It bridges the gap between high-resolution planar lithography and curvilinear device applications. By enabling direct transfer of microfabricated components onto 3D surfaces, CAS printing facilitates the creation of novel electronic architectures that were previously unachievable. This innovation empowers a range of applications in imaging, energy harvesting, biomedical sensing, and wearable technology.

 

Methodology: During CAS printing, the elastomeric balloon stamp, coated with a conformal adhesive layer, is pneumatically actuated to pick up the device arrays and press them onto target substrates, such as hemispherical shells, convex domes, or soft elastomers. Throughout the transfer process, strain distribution is analyzed using finite element analysis (FEA) to minimize distortion. The printed devices undergo electrical and optical testing before and after transfer to confirm performance retention. This methodology is compatible with a wide range of device materials and geometries, enabling seamless integration of silicon electronics, photodetectors, and solar cells onto non-developable surfaces.

 

Results and Conclusions: Using CAS printing, we demonstrated several functional devices: (1) a hemispherical photodetector array printed onto a dome-shaped shell showed stable photocurrent output over a wide angular range, confirming conformal contact and uniform light response. (2) A printed solar cell array preserved >95% of its power conversion efficiency after transfer, even under bending and mechanical cycling. (3) A 32×32-pixel shape-adaptive silicon imager was successfully transferred onto concave and convex surfaces, showing excellent mechanical integrity and optical performance. Integrated with a tunable lens, the imager achieved dynamic focal adjustment, replicating key features of human vision. (4) CAS printing was applied to fabricate a hemispherical retina-inspired photodetector array integrated with a neuromorphic processing unit. The system demonstrated a high-performance neuromorphic imaging on a curved elastomeric surface exhibiting contrast enhancement, temporal response, and signal amplification. These results collectively validate CAS printing as a robust, scalable, and versatile manufacturing technique that enables the fabrication of curvilinear and deformable electronics with high spatial resolution and mechanical adaptability. This method establishes a foundational toolset for the next generation of wearable, biointegrated, and optoelectronic systems.

Presenting Author: Zhoulyu Rao University of Illinois Urbana-Champaign

Presenting Author Biography: I am now a postdoctoral researcher at the University of Illinois Urbana-Champaign (UIUC). He received his Ph.D. in Materials Science and Engineering from the University of Houston in 2021, an M.S. in Chemistry from the University of Science and Technology of China in 2015, and a B.S. in Applied Chemistry from Xidian University in 2012. My research interest focuses on pioneering new electronic materials and devices to bridge the gap between engineering devices and biological systems, to overcome some great challenges in or related to imaging, healthcare, medicine, robotics, etc. To achieve this goal, my research spans from the creation of electronic materials/devices with high area coverage, ultrathin thickness, or softness/stretchability-outperforming counterparts achieved by traditional technologies, to validating the devices in small animal models.

Authors:

Zhoulyu Rao University of Illinois Urbana-Champaign
C. Yu University of Illinois, Urbana-Champaign