Photoaligned Nanorod Enhancement Films with Polarized Emission for Liquid‐Crystal‐Display Applications

Abstract

Semiconductor nanorods (NR) emit polarized light, which is expected to bring manifold benefits, in terms of brightness and color enhancement, for modern liquid-crystal displays (LCD). In this regard, photoaligned nanorod enhancement films (NREF) for color and polarization conversion for LCD backlights are introduced here. The photoinduced anchoring forces, by the photoalignment layer, stimulate well-ordered self-assembly of NR in the thin polymer films. Green and red emitting NR with a quantum yield of ≈80% are aligned unidirectionally and in-plane, showing a polarization ratio of >7:1 and a degree of polarization of >0.81. The photoalignment technique facilitates the fabrication of mixed and multiple stacked NREF for LCDs, which improves the color gamut and polarization efficiency, and is thus expected to increase the optical efficiency of conventional LCDs by ≈60%.

Synthesis of Anisotropic ZnSe Nanorods with Zinc Blende Crystal Structure

“…One‐dimensional (1D) semiconductor NCs, termed nanorods (NRs), are an important class of colloidal nanomaterials that experience strong carrier confinement in two directions, but less or even almost no confinement axially. Semiconductor NRs show linearly polarized emission, and were reported to be of advantage for efficient charge transport and separation, which make them attractive for applications in displays and other types of optoelectronic devices . Cd‐based II–VI NRs have been extensively studied with the highest degree of control in terms of size, shape, and crystal structure .…”

Circularly Polarized Luminescent Carbon Dot Nanomaterials of Helical Superstructures for Circularly Polarized Light Detection

“…Circularly polarized luminescence (CPL) has drawn increasing attention [1][2][3][4][5][6] for their promising potentials in wide-ranging applications including stereopsis, [7] optical storage devices, [8] biological sensors, [9][10][11] asymmetrical catalysis and synthesis [12][13][14][15] and security systems. [16] In order to realize circularly polarized luminescence, asymmetrical environment and phosphors are essential elements.…”

Multi‐Dimensional Quantum Nanostructures with Polarization Properties for Display Applications

“…One of the most representative examples is their use in enhanced polarized display. As one of the main LCD components, the polarizers are responsible for almost half of the light loss in display device . The next generation LCD technology, using linearly polarized light as the backlight, could vastly enhance the efficiency of LCD device by reducing light loss when polarized backlighting emission is filtered by the first polarizer .…”

“…Thus, it is expected that the aligned and uniform nanorods films would emit polarized light with high degree of polarization, therefore enhance the efficiency of the LCD technology . In this regard, several strategies have been developed in the last decade . With the assistance of an external electric field, nanorods could self‐assemble along the direction of the field lines and got the polarization ratios of 0.48 .…”

“…Ever since the first CdSe QDs based electroluminescence device was reported in 1994, the pursuit of lower energy consumption devices has never stopped. Replacing spherical QDs with fluorescent material that emits bright linearly polarized light with high color purity as the polarized backlight, could enhance the efficiency of LCD devices, by lowering the back light emission loss when passing through the first polarizer . Elongated anisotropic quasi‐one‐dimensional (q‐1D) nanorods, 1D nanowires (NWs), and two‐dimensional (2D) quantum wells (Figure ), provide such a source of polarized emission .…”