Information security films that can ensure personal privacy by reducing the viewing angle of display screens were fabricated by microlouver patterning and a ZnO nano-ink filling process. Optical simulation results demonstrated that all the microlouver films showed good security performances. Security performances were evaluated as calculated relative luminance ratios compared between the side and front. Based on the simulation results, microlouver films were fabricated by UV imprint lithography and nano-ink bar coating. However, distortion of the microlouver pattern occurred with the use of high-viscosity nano-inks such as ZrO 2 and TiO 2 , and the CuO-filled microlouver film suffered from very low optical transmittance. Accordingly, the effects of ZnO filling height on security performance were intensively investigated through simulation and experimental measurements. The fabricated microlouver film with a 75-µm-high ZnO filling exhibited a good relative luminance ratio of 0.75 at a 60° side angle and a transmittance of 44% at a wavelength of 550 nm.

In the current study, we prepared a LixLa3Zr2O12 ((Al, Ta) LLZO) powder doped with 0.2 mol of Al and Ta using the sol-gel method and subsequently used it to fabricate solid electrolyte pellets. In pellets with lithium content of 6.2 and 6.82 mol, a cubic phase and a lithium-deficient pyrochlore mixed-phase were respectively observed. However, when the lithium content was 8.06 mol, a lithium-excess phase was also observed. Meanwhile, at 7.44 mol lithium, the (Al, Ta) LLZO ceramic pellets showed a pure cubic garnet phase with no secondary phase. When lithium was added excessively, a non-granular morphology was observed at the (Al, Ta) LLZO fracture surface in which the grains were tightly bonded by the liquid phase formed during sintering. Nyquist plots of the pellets showed that the effect of grain boundaries was eliminated and the pellets exhibited a high lithium ion conductivity of 4.26 × 10−4 S/cm. Using spin coating and multi-step heat treatment, we deposited LiCoO2 (LCO) thin films on (Al, Ta) LLZO pellets to form cathodes. There was no significant interdiffusion between the LCO cathode and (Al, Ta) LLZO solid electrolyte and morphological analysis indicted that a thin interfacial layer (~10 nm) was formed between the LCO and the electrolyte. Finally, we demonstrated an all-solid-state rechargeable battery in the form of a coin cell comprising of an LCO cathode, Li metal anode, and (Al, Ta) LLZO solid electrolyte, which could yield a discharge capacity of ~100 mAh/g.