Photosensitive precursors
are developed for the printing of 2D and 3D conductive structures
via blue laser projection printing. With the assistance of a photosensitizer,
metal nanoparticles can be efficiently photosynthesized under laser
irradiation of low light intensity (45–290 mW cm–2). By projecting well-defined laser patterns on the precursor, corresponding
2D metal structures with the finest line of about 50 μm can
be formed on various substrates including flexible polymer thin films,
curved substrates, and ground glass. Moreover, complex 3D objects
with nanoparticles embedded in the polymeric matrix are constructed
via 3D printing combining photoreduction of the metal precursor and
photopolymerization of resin. The as-prepared structures exhibit promising
conductivities after sintering (in the order of magnitude of 106 S m–1). A possible mechanism of photochemical
synthesis of metal nanoparticles upon exposure to blue laser is proposed.
The high efficiency and low cost of the technique, the complexity
of the structures prepared, and the applicability to various substrates
and metals (including silver, gold, and palladium) promise practical
applications of this approach in the printed electronics industry.