A study of the possibility of conducting selective laser processing of thin composite electrochromic Ni(OH)2-PVA films

The surfaces of thin composite electrochromic Ni(OH)2-polyvinyl alcohol films, deposited by the cathodic template method on FTO glass substrates, were proposed to be processed using laser radiation. The processing of these films was carried out in a colored state with a laser beam of a semiconductor emitter with a wavelength of 650 nm (red) with a pulse duration of 3,000 μs, the beam diameter was about 40 μm. The energy at a single point was 37.5 J/cm2. The result was a film with microholes of about 80 μm. The transparent areas of the surface did not exhibit electrochromic properties, which indicated the absence of the original electrochromic coating. The study of the properties of the laser-processed film following a certain pattern showed that the characteristics of composite Ni(OH)2-polyvinyl alcohol coatings had changed significantly. On the one hand, the coloration depth of the films decreased by several percent, on the other hand, the specific electrochemical characteristics increased significantly. The study also showed that laser processing did not lead to significant changes in the main properties of the transparent electrically conductive layer – color and resistance. Before and after laser processing, the surface resistance of FTO glasses was 12.1±0.9 and 14.4±1.2 Ohm/sq., respectively.  In addition, it was found that the processing of Ni(OH)2-polyvinyl alcohol films improved the adhesion of the latter to the surface of FTO glass. Based on the data obtained, a selective method was proposed for modifying thin colored films deposited on transparent conductive oxides (FTO, ITO, AZO) by visible laser radiation. This approach to changing the properties of films can be useful for areas related to the development of sensors, microelectronics, solar cells, small-sized current sources, electrodes with high efficiency, etc.