Influence of aminated graphene nanosheets on electro–optical performance and nonlinear optical properties of nematic liquid crystal

• Published in: Journal of molecular liquids Vol. 375; p. 121337
• Main Authors: Ostovari, F., Dehghani, Z.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2023
• Subjects: Aminated graphene nanosheets; Dielectric anisotropy; Nematic liquid crystal; Nonlinear optics; Threshold voltage; Dielectric anisotropy; Threshold voltage; Nematic liquid crystal; Aminated graphene nanosheets; Nonlinear optics
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2023.121337

•Analysis of AGM nanosheets indicates the formation of graphene nano layers with amine functional groups.•Aminated graphene (AMG) nanosheets with different compositional percentages have been dispersed in E7.•The cells with two initial alignment layers including homogeneous (HA) and vertical (VA) alignment orientations were prepared.•The dielectric anisotropy, threshold voltage and the NLO properties of prepared cells were investigated.•The effect of different powers of laser on the NLO properties of 0.1 %wt AMG/NLC in VA configuration were studied. In this research, aminated graphene (AMG) nanosheets with different compositional percentages have been dispersed in nematic liquid crystal (NLC) E7 with special initial ordering including homogeneous (HA) and vertical (VA) alignment orientations. Doping of AMG nanosheets into E7 can improve their electro-optical properties considerably. First of all, some analyzes of AMG nanosheets such as TEM, SEM, XRD, Raman, FTIR and Zeta potential were investigated to guarantee their quality. Then the dielectric anisotropy (Δε) of the NLC and doped ones with AMG was studied in different temperatures in details. Further, it has been found that due to dispersion of AMG, the threshold voltage (Vth) of prepared cells is reduced by up to 17% when compared to E7 nematic cells due to the reduced splay elastic constant (K11), as well as increased Δε, in the mixtures of NLCs. Also, according to the findings, nonlinear optical (NLO) properties of NLC were strongly affected by doping with AMG nanosheets that were examined through the Z-scan method using the laser beam at 632.8 nm wavelength. Doping significantly increases the NLO responses of NLC, which reaches up to 96.79 ×10-7(cm2/W) and 58.5 ×10-2(cm/W) for 0.1 %wt doped one in VA for nonlinear refraction (n2) and absorption (β) coefficients, respectively.