Four-dimensional printing with embedded photoluminescence is emerging as an exciting area in additive manufacturing.  Slim polymer films patterned with an array of cylindrical waveguides (waveguide-encoded lattices, WELs) can be fabricated by localizing light within a photo-polymerizable formulation. Luminescent WELs have potential applications as solar cell coatings and smart, planar optical components. 

Our findings in this study show that luminophores play a non-innocent role in the photopolymerization process. We highlight the necessity for both careful consideration of the photopolymer formulation and a real-time monitoring approach to enable the fabrication of high-quality micropatterned luminescent polymeric films. 

Our paper has been selected as an ACS Editor’s Choice due to the potential impact our findings have on diverse applications from additive manufacturing through to light-harvesting devices! 

Figure caption: In this study we observe an electron-transfer interaction between the photoinitiator for polymerisation and the luminophore, which changes the kinetics of the polymerisation process, both in non-patterned and micropatterned films.