Electrical Behavior of Liquid Crystal Device with Dielectric Nanoparticles

Nowadays, the development of new devices based on liquid crystal (LC) materials requires improved tuning characteristics according to the application. One approach for this improvement is the use of nanomaterials with the capability of modifying the effective properties of the doped LC mixture. In this work, we analyze the electrical behavior of a titanium dioxide (TiO2) nanoparticle-doped liquid crystal cell using an equivalent circuit. The circuit parameters have been obtained using the impedance spectroscopy technique and time response measurements. The particularity of the samples designed is that the nanoparticles are not dispersed in the LC. Instead of that, nanoparticles are randomly deposited on one of the electrodes. Measurements show that the presence of the nanoparticles increases the temperature sensitivity of the equivalent cell capacitance and the capacitance difference between switched and nonswitched states. These results could be quite useful in the design of novel liquid crystal electronic devices and sensors.V.M. wants to express his gratitude to the Ministerio de Economía y Competitividad for his doctoral grant (FPI research fellowship Ref. BES-2014-070410). M.C.-G. wants to express his gratitude to the Ministerio de Economía y Competitividad for his postdoctoral grant (FPI (POP) research fellowship Ref. BES-2014-070964). This research was funded by the Ministerio de Economía y Competitividad, grant numbers TEC2016-77242-C3-1-R and TEC2016-77242-C3-2-R Grant (AEI/FEDER, UE funds) and the Comunidad de Madrid and FEDER program through the SINFOTON2-CM (grant number S2018/NMT-4326) program