Functional Film with Electric-Field-Aided Aligned Assembly of Quantum Rods for Potential Application in Liquid Crystal Display

Harnessing the unique polarized light emission characteristic from semiconductor quantum rods (QRs) necessitates their large-area unidirectional alignment. Herein, the aligned assembly of CdSe/CdS QRs is demonstrated by fabricating a functional film on a micrometer-spaced interdigitated electrodes substrate over an area of ≈1.3 cm². The external electric field is used to control the position and orientation of QRs which is later frozen by the polymerization of reactive mesogen under the exposure of UV light. Under the fluorescence microscope, a judicious change in the QRs emission intensity with the polarizer axis positioned parallel and perpendicular to the alignment direction suggests the optical anisotropy. The degree of alignment of QRs is characterized by the polarization ratio which is measured 0.48 from the photoluminescence spectra. It is found that factors such as optimal QRs concentration and the presence of liquid crystal contributed for better QRs alignment. Such films may be advantageous for liquid crystal display devices to accomplish light polarization and wider color gamut.