Inorganic nanosheets-based electro-optic devices with single-pixel full-color and gray scale control

Developing single-pixel full-color liquid crystal displays (LCDs) that do not require orientation layers and color filters is highly desirable since this would allow to better optimize their image resolution and light utilization efficiency while considerably reducing fabrication cost. However, so far, organic polymers have shown only limited color modulation range and inorganic materials have mostly been limited to on-and-off switches. Here, we report single-pixel full-color modulation along with gray scale control in electrically responsive two-dimensional (2D) inorganic sheets using alpha-ZrP and Ca2Nb3O10 as our model materials. We demonstrate modulation of transmitted light spanning the entire visible spectrum at an ultralow driving electric field strength (below 10.4 V mm(-1)), which is one to two orders of magnitude lower than required for conventional organic liquid crystals. We attribute this unusually high performance to the surface charge, the ultra-small thickness, and the large electro-optic anisotropy of the 2D sheets used in this study. To the best of our knowledge, this is the first demonstration of an LCD that efficiently combines gray scale and full-color modulation without the need for color filters or orientation layers. Our work thus opens the door to new types of LCDs and the simplicity of our setup allows its potential integration in various other information and image display systems.