Spontaneous liquid crystal alignment on solution-derived nanocrystalline tin-oxide films

We investigated the use of solution-derived nanocrystalline SnO2 films to promote the self-alignment of liquid crystal (LC) molecules. Uniform and homogeneous LC alignment was spontaneously achieved by using these substrates. LC molecules with a preferred orientation were aligned along the filling direction, and the LC alignment was maintained via van der Waals force by nanocrystals of the solution-derived SnO2 films. This phenomenon did not occur in amorphous-phase SnO2 films. Nanocrystalline SnO2 films were grown at annealing temperatures greater than 400 °C. Although the average transmittances of the SnO2 films degraded slightly as the annealing temperature increased, the values were similar to those of conventional polyimide films. Electrically controlled birefringence mode cells fabricated using the solution-derived nanocrystalline SnO2 films exhibited superior electro-optical characteristics, indicating that this approach will allow the fabrication of advanced LC displays with high performance through a simple fabrication process.