Unidirectionally aligned bright quantum rods films, using T-shape ligands, for LCD application

Unidirectionally aligned nanorods (NRs) are of great importance for different applications, including displays, lighting, and photodetectors. Recently, many alignment techniques were studied to align quantum rods (QRs). However, the brightness of these films, due to the limited concentration of aligned quantum rods in the film, is not enough for their implementation as brightness enhancement films (BEFs) in displays. This can be ascribed to the poor miscibility of quantum rods in polymer and strong concentration dependence of the polarized emission. The ligands of NR are very important for the alignment and brightness. In this article, we proposed a ligand combination comprising T-shape promesogenic phosphonic acid, which on being photoaligned provides mutually parallel alignment of the quantum rods. The T-shape ligands enable the fabrication of hybrid films with a QRs concentration as high as 10 wt.%`-20 wt.% retaining high brightness and luminescence polarization property. Later, we used these films in the in-plane switching (IPS) display backlight that shows the color gamut up to 121% of national television system committee (NTSC) (CIE1931), liquid-crystal display (LCD) efficiency up to 7.9%, power efficacy 103 +/- 2 nits/W, and the high brightness of similar to 550 +/- 10 nits. Thus, the proposed ligands can be used for the alignment of a variety of nanorods.

Automated summary

In this study, a new ligand combination is proposed to achieve mutually parallel alignment of nanorods, leading to the fabrication of high concentration and high brightness hybrid films. These films exhibit excellent performance in display backlight applications.