Fabrication of Meso-Lens Arrays Using Non-Close-Packed Colloidal Monolayers

Abstract

A microlens array is the optical element which has many lenses with a diameter of several to hundreds micrometers on the substrate surface. In the present study, we have tried to prepare the meso-lens array with a diameter of hundreds nanometers from the non-close-packed (NCP) colloidal monolayers, which are prepared by the convective self-assembly (CSA) using a quartz glass substrate and the silica particles grafted with cationic polyelectrolyte, poly(vinylbenzyl trimethylammonium chloride) (PVBTA). The PVBTA-grafted silica particles and the glass substrate were applied to the CSA process to prepare the NCP monolayers, and then the obtained monolayers were annealed in a muffle furnace for several hours. The annealed particle monolayers were observed by a scanning electron microscope (SEM) and an atomic force microscope (AFM). As a result, we found that the height of the silica particles decreases with an increase in annealing time, and the partially fused silica particles integrate with the quartz glass substrate to form a meso-lens array.

Graphical Abstract

SEM images of PVBTA-grafted silica particle layers annealed at 1423 K for different time periods: (upper row) top views of SEM images; (bottom row) SEM images tilted 45 degrees.