Homogeneous liquid crystal alignment of spin-coated strontium oxide and its application for superior LCD performance

Abstract

Strontium oxide (SrO) films were fabricated via solution processing and used as a liquid crystal (LC) alignment layer. The effect of the molar concentration of Sr on the properties of these films was analyzed. Some treatment on the alignment surface is generally required to align LC molecules. However, LC molecules aligned spontaneously on SrO films that were fabricated using our solution process; this alignment occurred along the direction of LC injection. Uniform LC alignment was achieved on SrO films with Sr molar concentrations between 0.1 and 0.3 mol; however, randomly aligned LCs were observed at 0.4 mol Sr. In addition, LC cells with excellent electro-optical characteristics were obtained. The threshold voltages and response times of LC cells fabricated by SrO films decreased as the molar concentration of the Sr component increased. We were able to obtain values that are competitive with those demonstrated by conventional rubbed LC cells. It is important to investigate the alignment property and electro-optical property for realization of a suitable LC application. Graphical abstract exhibits the alignment property (upper POM image) and electro-optical property (applied voltage-transmittance graph) of LC cell fabricated by SrO films. LC cell with 0.1, 0.2 and 0.3 M shows uniform alignment state. Moreover, voltage-transmittance of LC cells based on SrO film was measured and compared to that of rubbed PI. The results show the possibility of advanced LC applications.