Three-dimensional Tunable Orientation of Silver Nanowires in Nematic Liquid Crystals via Photo-alignment

The self-assembly of silver nanowires (AgNWs) is desirable for practical applications in liquid crystal displays (LCD); however, it remains challenging for the tunable orientation and reorienta-tion of AgNWs in three dimensions. In this work, the properties of AgNWs were studied and their orientation and reorientation were realized by the combination of the photo-alignment technology and electric field. The orientation of AgNWs dispersed in nematic LCs in the plane of the sub-strates was seen under a polarizing optical microscope (POM) without the analyzer. The AgNWs were aligned perpendicular to the LC director n. Then the AgNWs were reoriented by 90 degrees under the blue polarized light which were also perpendicular to the LC director n. And the multi-micro-domain orientation of AgNWs could be assembled through photo-masks. The order parameter of AgNWs was above 0.9. The vertical orientation and reorientation of AgNWs in LCs could be tuned by the applied electric field across the cell. The angle between the main axis of AgNWs and the substrates could be increased as the applying voltage increased. Through the combination of photo-alignment and electric field, AgNWs can be dynamically oriented in the multi- micro- and macro-domains in three dimensions. The threshold voltage (Vth) and response time of the nematic LCs doped with and without AgNWs were measured for LCD application.