不同衬底下激光后处理对结构色呈色性能影响研究

Abstract

Objective With the continuous development of science and technology, it is of scientific significance to construct a structural color with a special color effect and good stability based on the nanostructure. At present, various artificially prepared structural color tuning methods are put forward, such as traditional nanoimprint lithography, ultrafast laser direct writing, microfluidics, and inkjet printing. Although it is possible to produce nanostructures with good periodicity and various patterns, the cost and complexity of the process also restrict the development of technology. To this end, twodimensional ordered templates with planar hexagonal closepacked structures are prepared by the gasliquid interface assembly method on silicon wafers, and silicon wafers with a certain thickness of SiO 2 in our study, and metal thin films with different thicknesses are prepared by the magnetron sputtering method. Then the deformation degree of the periodic surface is changed by posttreatment of 532 nm pulse laser to realize the modulation of structural color samples. Color modulation is carried out by regulating the changes in microstructure morphology.Methods The fabrication process of the periodic polystyrene (PS) microsphere substrate is divided into two steps. First, a polymer sphere monolayer is assembled at the gasliquid interface and then transferred to the Si/SiO 2 substrate. Second, the Au films with different thicknesses are deposited on the abovementioned PS colloidal crystal template by a radio frequency (RF) magnetron sputtering technique. Then a 532 nm pulsed solidstate laser system (EP10 -1, Changchun New Industries Optoelectronics Technology Co. , Ltd. ,) is employed to posttreatment the ordered surface with metalcoated colloidal crystal by changing different scanning speeds. The laser system generates a train of 5 ns laser pulses at a repetition rate of 1 kHz. The laser beam is focused by a convex lens with a focal length of 160 mm, and the diameter of the focused laser beam is about 180 μm at the focal plane. By adopting such a method, vivid colors such as cyan, orange, and yellow are experimentally obtained, and the saturation is also improved by adding a SiO 2 layer.Results and Discussions With Si as the substrate and the coating time fixed at 20 s, 80s, and 120 s, the peak positions of the reflectance spectrum shift gradually from 609 nm, 602 nm, and 593 nm to 485 nm, 519 nm, and 524 nm in the longwave band, and from 420 nm, 416 nm, and 401 nm to 394 nm, 375 nm, and 368 nm in the shortwave band respectively, as the laser scanning speed decreases. At a fixed laser scanning speed of 50 mm/s, the peak positions of the reflectance spectrum of the sample first shift to short wavelength from 585 nm to 538 nm with the increasing coating time, and then turn to 559 nm in the long wavelength direction. When the laser scanning speed increases to 200 mm/s, with the rising coating time, the spectrum shows a slight blueshifted trend and Δλ =17 nm (Fig. 6). In addition, by adding the SiO 2 layer, under the scanni...