Butterfly wings as natural photonic crystal scaffolds for controllable assembly of CdS nanoparticles

Abstract

A facile solution process is developed, through which butterfly wings are taken as natural photonic crystal (PhC) scaffolds to control the synthesis and assembly of CdS nanocrystallites, and thus to achieve novel optical nanocomposites with unobtainable PhC features. Practically, the original wings can be activated by an EDTA/DMF suspension to first serve as in-situ reactive substrates for CdS seeds, and then provide the PhC structures for the following heterogeneous deposition of CdS nanoparticles (nano-CdS). The obtained nano-CdS covering precisely preserves the efficient structure details of the natural PhCs from macro-scale down to ∼100 nm. In the resulting nano-CdS/butterfly wing composites, the assembly patterns of nano-CdS can be controlled at two levels: one is the PhC structures (>100 nm) decided by the wing scale hierarchy, the other is the nano-CdS small clusters (<100 nm) distributed on the PhC structures. Such a combination of nano-CdS and butterfly wings should create novel optoelectronic properties, and relevant ideas could inspire the investigation of PhC materials.