Molecular Inks for the Development of Complex 3D In‐Mold Electronics

In‐mold electronics (IME) is an emerging area of interest for printed electronics manufacturers that enables the development of lightweight, 3D human‐machine interfaces (HMIs) which can be embedded into injection molded plastic parts. The challenge in developing 3D IME parts is the harsh mechanical demands that thermoforming puts on the printed functional inks, often leading to cracking and loss of conductivity. Here, we demonstrate that screen‐printable molecular inks (MINKs) containing metal carboxylate salts can overcome this limitation. During thermoforming MINKs melt into a stretchable viscous liquid, allowing printed tracks to elongate up to 100% without cracking. Following thermoforming, the metal carboxylate salts can be converted to conductive metal tracks using intense‐pulsed light (IPL) sintering or thermal energy, producing highly conductive 3D circuits. Subsequent electroless copper plating can further enhance conductivity, reducing the sheet resistance by a factor of 60. The combination of tunable processing behavior, high elongation, and excellent electrical performance enables the development of 3D structures that are not attainable with commercially available inks, advancing the design and complexity of next‐generation IME devices.