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 SnO ₂ 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.