High contrast ratio electrophoretic displays based on high structural stability and high transmittance microcup.

In the age of Internet of Things, electrophoretic electronic paper (E-paper) holds a unique position in the display area due to its energy-saving, environmental friendliness, excellent readability in strong ambient light, and eye protection. Compared with E-papers of microcapsules, microcups have several advantages including higher mechanical strength, lower production costs, and better feasibility to show multiple colors with high contrast, thereby making it a significant research interest. However, there is currently no systematic study on the structural mechanics and display performances of microcups. Herein, we simulate the structural stability of microcups with various shapes and sizes during nanoimprint process, and also calculated the aperture ratio of these microcups. We fabricated devices with different geometrical morphologies to verify the microcups for achieving a balance between high contrast, high transmittance and high structural stability. This study provides a new method for designing and manufacturing the E-papers of microcups in using nanoimprint roll-to-roll (R2R) production.

Fluorescent, multifunctional anti-counterfeiting, fast response electrophoretic display based on TiO2/CsPbBr3 composite particles.

Traditional optical anti-counterfeiting (AC) is achieved by static printed images, which makes them susceptible to lower levels of security and easier replication. Therefore, it is essential to develop AC device with dynamic modulation for higher security. Electrophoretic display (EPD) has the advantages of low power consumption, high ambient contrast ratio, and capability of showing dynamic images which is suitable for dynamic AC applications. Herein, we prepared a dynamical AC device based on a fluorescent EPD, and achieving the image switch between black, white, and green fluorescence states under the dual-mode driving (electronic field and UV light). We loaded perovskite quantum dots (CsPbBr3) onto the TiO2 particles and further prepared fluorescent electrophoretic particles TiO2/CsPbBr3-3-PLMA (TiO/CPB-3) by grafting and polymerizing method. In addition, we fabricated the AC devices based on the fluorescent EPD, which exhibits the multifunctional AC, where the fluorescent EPD has a fast response time of 350 ms, a high contrast ratio of 17, and bright green fluorescence. This prototype demonstrates a new way for future dynamic AC and identification.