Selectively Manipulating Upconversion Emission Channels with Tunable Biological Photonic Crystals

Photonic crystals have been demonstrated as promising platforms for manipulating emission properties of quantum emitters. However, because of the limitation of fabrications, only few types of artificial photonic crystals have been fabricated. In contrast, the earth provides us rich biological photonic crystals with unique optical features, while most of them are still unexplored for such applications. Here, we employed the biological photonic crystal of a butterfly wing as a tunable platform to manipulate upconversion luminescence of lanthanide-doped nanoparticles (NaYF4:Yb3+,Er3+). Through tuning the bandgaps of the biological photonic crystals, we selectively controlled the red and green emission channels of NaYF4:Yb3+,Er3+ and achieved different luminescent colors. We also measured the time-resolved luminescence, investigated the near-field interactions between photonic crystals and the upconversion nanoparticles, and demonstrated that the enhanced radiative decay rates induced by the increased local density of photonic states and the perfect absorption effect of the pigments underpinned the different luminescent colors. Our tunable photonic upconversion hybrid nanostructures are beneficial for biophotonic devices.