Enhanced Photorefractive and Third-Order Nonlinear Optical Properties of 5CB-Based Polymer-Dispersed Liquid Crystals by Graphene Doping

Abstract

The enhanced photorefractive and third-order nonlinear optical properties of graphene/graphene oxide (GO)-doped polymer-dispersed liquid crystals (PDLC) were studied by two-beam coupling and z-scan methods. A higher interior electric field will be produced according to the photorefractive performance because of the high electrical conductivity of graphene. The doping of graphene also improved the uniformity of alignments of 4-cyano-4′-pentylbiphenyl (5CB) in PDLC because the rod-shaped liquid crystals tended to align along the surface of sheet structures and the alternate positions of the hexagons on the graphene surface matched well with the alkyl chains of 5CB molecules. Higher third-order nonlinear refraction and absorption coefficient can be attributed to the geometric relationship between graphene and 5CB. The GO-doped samples exhibited higher photorefractive efficiency, third-order nonlinear refraction, and absorption coefficient than undoped PDLC samples, but lower values than the graphene-doped samples because of the nonconducting nature of GO and/or weaker surface matching.

Graphitic nanosheets via two-dimensional polymerization enhancing organic all-optically controlled photorefractive performance

“…It was well known that the charge diffusion depends on the electric conductance in organic photorefractive device [17,20], which might be strengthened by excellent electric conductors. In this case, the 2D carbonaceous materials are able to be applied as the electric conductor to strengthen the built-in electric field in organic photorefractive devices [21][22][23][24], similarly to inorganic nanowires [25][26][27][28][29][30][31]. At the same time, the size of 2D carbonaceous materials is an important factor to guarantee the strengthening of built-in electric field, instead of quenching.…”

2D Material Liquid Crystals for Optoelectronics and Photonics

“…In addition to graphene (exfoliated from graphite), materials that can be reduced to monolayer size have been shown to include: graphene oxide (from graphite oxide); transition metal dichalcogenides (TMDCs) 2 and MoTe 2 ; and hexagonal boron nitride (h-BN) amongst countless others. The possibilities for applications of these materials are almost limitless, owing to the diverse properties that they exhibit.…”

“…Firstly, 2D material particles can be dispersed in a conventional liquid crystal host. 2,3 Alternatively, 2D materials dispersed in specific solvents have been shown to display lyotropic liquid crystalline phases within certain ranges of 2D material concentration.…”

Incorporation of graphene oxide into C12E4/C12mimBr hybrid lyotropic liquid crystal and its thermo-sensitive properties

“…[10][11][12] Therefore, long-chain alkyl-imidazollium ionic liquids has become hotspots in research fields due to its rich phase behavior. [19][20][21] As a special carbon material, graphene is the one with the most potential due to its outstanding physical, chemical and electronic properties. 16 Moreover, Zhang et al also compared two ternary systems C 16 mimBr/H 2 O/C 10 H 21 OH and CTAB/H 2 O/C 10 H 21 OH, and investigated the effect of hydrophilic group on the structure of LLC and finally got the formation mechanism of complex crystal.…”