Spectral tuning of biotemplated ZnO photonic nanoarchitectures for photocatalytic applications

The photocatalytic activity of a flat surface can be increased by micro- and nanostructuring the interface to increase the area of the contact surface between the photocatalyst and the solute, moreover, optimize charge carrier transfer. Further enhancement can be achieved by using photonic nanostructures, which exhibit photonic band gap (PBG). Structurally colored butterfly wings offer a rich “library” of PBGs in the visible spectral range which can be used as naturally tuned sample sets for biotemplating. We used conformal atomic layer deposition (ALD) of ZnO on the wings of various butterfly species (Arhopala asopia, Hypochrysops polycletus, Morpho sulkowskyi, Polyommatus icarus) possessing structural color extending from the near UV to the blue wavelength range, to test the effects arising from the nanostructured surfaces and from the presence of different types of PBGs. Aqueous solutions of rhodamine B were used to test the enhancement of photocatalytic activity that was found for a...