We investigated the properties of nematic liquid crystal device (NLC) doped with titanium (Ti) nanoparticle (~100nm). The electro-optic (EO) properties of LCs changed according to Ti nanoparticle doping concentration. Ti nanoparticles in the NLC cells focused the electric field flux and strengthened the electric field. Further, Ti nanoparticles in NLC molecules may trap charged ionic impurities and suppress the screen effect, leading to a stronger electric field and the van der Waals dispersion interactions between NLC molecules and the alignment layers. We also simulated the boundary conditions of the Ti nanoparticles in the electric field using Ansoft Maxwell software. Our experimental results agreed with the phenomenon predicted by software simulation based on general physical theory. Synthetically, at a 1.0 wt. % Ti nanoparticle doping concentration, the NLC cells showed the best EO properties, such as a low threshold voltage (1.25V), fast response time (13.2ms), and low pretilt angle (3.90°).

We demonstrate self-aligned and high-performance liquid crystal (LC) systems doped with 1-dimensional (1D) chain-like clusters of CuInS₂ (CIS)–ZnS core–shell quantum dots (QDs). By changing the cell fabrication method of the LC–QD composites, we can selectively control the orientation of the LC molecules between the homogeneous and homeotropic states without conventional LC alignment layers. The homeotropic alignment of LCs was achieved by random dropcasting and the homogeneous alignment was performed using a capillary injection of LC–QDs due to the random or linear diffusion of QD clusters into ITO defects. The electrically compensated bend (ECB)- and vertically aligned (VA) mode LC displays (LCDs) containing our LC–QD composite both showed superior electro-optic (EO) properties. A 37.1% reduction in the threshold voltage (V_th) and a 36.6% decrease in the response time were observed for ECB mode LCDs, and a 47.0% reduction in the V_th and a 38.3% decrease in the response time were observed for VA mode LCDs, meaning that the proposed LC–QD composites have a great potential for the production of advanced flexible LCDs.

In this paper, nanoimprint lithography was utilized to transfer a nano-pattern (NP) onto a homeotropic polyimide (PI) surface for use in liquid crystal displays (LCDs). The nano-patterned silicon mold was fabricated by laser interference lithography. A NP PI layer acted as the homeotropic alignment layer to easily and uniformly align the liquid crystal (LC) molecules. A NP LC cell with a NP PI layer was successfully operated as a vertical aligned LCD, and its performance was evaluated. The threshold voltage and response time of the NP LC cell were 2.472 V and 22.7 ms, respectively. In addition, the NP LC cell was characterized by a high thermal budget. Therefore, the competitive performance of the NP LC cell could allow new approaches to replace the conventional rubbing process in display technology.

We report the doping effect of graphene quantum dots (QDs) in a nematic liquid crystal (NLC) device. The use of graphene QDs leads to improved electro-optical (EO) properties, such as faster response times and a decreased threshold voltage. A 14.8% reduction in the threshold voltage (3.165 V), a 30% decrease in the falling time (4.9 ms) and a 63.6% decrease in the rising time (2.4 ms) were observed for twisted nematic (TN) LC devices (LCDs) that were doped with QDs. We confirm that the doping of the TN-LCD with graphene QDs reduces the field-screening effect, which is caused by impurity ions, whereas the other properties of conventional TN-LCDs are maintained.

We investigated the surface reformation of poly(dimethylsiloxane) (PDMS) elastomers by means of ion beam bombardment for fabricating wrinkle structures. Oxidation on the PDMS surface formed a silica-like outer layer that interacted with the inner PDMS layer, leading to the formation of wrinkle structures that minimized the combined bending energy of the outer layer and stretching energy of the inner layer. In addition, we controlled the amplitude and period of the wrinkle structures by adjusting the PDMS annealing temperature. As the PDMS annealing temperature was increased, the amplitude and period of the wrinkles formed by IB irradiation changed from 604.35 to 69.01 nm and from 3.07 to 0.80 μm, respectively.