Influence of cation substitution on dielectric properties and electric conductivity of 6CB liquid crystal with Me₇GeS₅I (me = Ag, Cu) superionic nanoparticles

Fréedericksz Transitions in 6CB Based Ferronematics—Effect of Magnetic Nanoparticles Size and Concentration

“…The increase in capacitance can be caused by an increase in conductivity due to the high volume concentration of nanoparticles. A similar effect was observed for 6CB doped with Me 7 GeS 5 I (Me = Ag, Cu) nanoparticles [24]. Moreover, for these two samples, threshold voltage and magnetic field, i.e., values of voltage and magnetic field, at which the transition begins, are significantly shifted to lower values, which can be seen from the position of the arrows, indicating the beginning of Fréedericksz transition.…”

Influence of X7GeS5I (X = Ag, Cu) Superionic Nanoparticles on Structural Changes in Nematic Liquid Crystal

“…The reason for the different sensitivity in SAW and optical investigations could be due to the different initial orientation of LC molecules and probably also due to some imperfections on evaporated golden electrodes on the both delay line and optical glass. Previous results obtained investigating the dielectric properties of 6CB doped with superionic nanoparticles Cu 6 PS 5 I showed that these nanoparticles do not significantly affect the dielectric permittivity of 6CB NLC [30,38] that partly corresponds with presented results. In addition, the similar behavior we have registered in both acoustic and light transmission investigation in the case of superionic nanoparticles Cu 6 PS 5 Br as dopant dispersed in the same NLC host (6CB) but with different stability and development of switching process [39].…”

“…Developments in the case of other samples are characteristic of several unanticipated humps, like in the case of pure 6CB. This behavior confirms the fact that the properties of LC doped with superionic nanoparticles can essentially depend on the properties of the host LC [30]. The threshold voltage in both NLC compounds increased markedly comparing with the pure one, already at the lowest concentration.…”

“…The significantly larger change of SAW attenuation comparing with that of pure NLC and by that the larger effect of doping was evidently detected only for highest concentration (0.10 wt%) of Ag 7 GeS 5 I-XXL nanoparticles. A similar difference in the behavior of these two kinds of dopants was also registered in the case of conductivity investigation [30] and is attributed to the generation of ions due to the interaction of Ag 7 GeS 5 I-XXL nanoparticles with neutral impurities that occur during their synthesis. The memory effect observed under decreasing field in SAW measurements represents about ~10-20% of initial value, however, it depends on the concentration.…”

“…The shift of transition temperature T NI is actually more distinctive in the case of Cu 7 GeS 5 I-XXL nanoparticles. Another reason for the decrease of T NI can be related to the increasing volume of impurities occurring in the NLC during its synthesis, the increase of nanoparticle concentration is also responsible for the conductivity behavior [30,32]. The temperature dependences of SAW attenuation measured for the NLC consisting of both Ag7GeS5I-XXL and Cu7GeS5I-XXL nanoparticles and all concentrations (0.01, 0.05, and 0.10 wt%) are illustrated in Figure 7.…”