Printing continuous metal structures via polymer-assisted photochemical deposition

Abstract: Patterning complex metallic structures via additive manufacturing (AM) has broad applications in energy, medical and aerospace industries. Current AM methods are often limited by high processing temperature, discontinuous film deposition and/or low product conductivity and reflectivity. We present a versatile room-temperature metal printing technique based on polymer-assisted photochemical deposition (PPD). Two-dimensional (2D) and three-dimensional (3D) printing of silver, gold and platinum structures with feature sizes as small as 5?µm are demonstrated on various substrates, including silicon, glass, polymers and biocompatible hydrogels. The PPD-printed metal films are continuous and smooth (roughness <3?nm) even at ultra-low thicknesses (<10?nm), and highly conductive (∼3×10⁵?S?cm⁻¹) and reflective comparable to that of vacuum deposited counterparts. This breakthrough in advanced AM technique holds great promise for low-cost, fast and distributed manufacturing in optics, electronics and robotics.