Flexible electronics printing has rapidly progressed thanks to innovations in material science and printing processes. In traditional methods, conductive inks or pastes are patterned via screen printing, inkjet, or other techniques. However, integrating these processes into a fully printed workflow—where active and passive electronic components are built layer by layer—remains a key challenge.
Recent studies highlight the compatibility of additive manufacturing (3D printing) with functional printing, enabling multi-layer structures that incorporate not just conductive traces but also insulating and semiconducting layers. For example, printing sensors directly onto curved or flexible substrates can eliminate the need for separate assembly processes, thereby reducing cost and complexity. One of the largest bottlenecks, however, is achieving robust adhesion and electrical performance across diverse substrate materials like polyimide, PET, or textile-based fabrics.
The paper reviews various printable materials, such as metal nanoparticle inks (silver, copper) and carbon-based conductors (graphene, CNT), examining their sintering requirements and the trade-off between conductivity, flexibility, and production speed. It also explores the use of UV-curable polymers for insulation and encapsulation, noting that the mechanical stability of these materials under repeated bending or stretching is an ongoing concern.
Industrial adoption depends not only on performance metrics but also on the scalability of these techniques. Conventional screen printing remains an industry standard for mass production, but its resolution is limited, making it less suited for fine-feature electronics. Digital methods like inkjet or aerosol jet printing offer higher precision but may have lower throughput. Thus, a hybrid approach—combining screen printing for bulk layers and digital printing for fine features—could accelerate commercialization.
The authors conclude that while the technology has reached a level of maturity sufficient for select niche applications (e.g., wearable sensors, RFID tags), further improvements in material ink formulations, curing processes, and printer hardware are necessary. Collaborative efforts between material scientists, mechanical engineers, and electronics manufacturers are vital to realize the potential of fully printed electronics for mainstream production.
