Optically Addressable Photoaligned Semiconductor Nanorods in Thin Liquid Crystal Films for Display Applications

The local optical anisotropy of 1D semiconductor nanorods (NRs), which results in anisotropic absorption and polarized emission, is important for various applications. Thin films of photoaligned, oriented NRs offer not only polarized emission but also anisotropic absorption at the macroscopic scale. Based on this anisotropic absorption, two kinds of optically addressable photoemissive displays are presented, which employ polarized backlight in combination with a liquid crystal (LC) based polarization rotator to control the down conversion emission intensity of a photoaligned NR/liquid crystal polymer (LCP) composite film. The first alternative “fixed information display” utilizes pattern aligned NRs, with an orthogonal easy axis in two domains, resulting in optical contrast in neighboring domains. The second option “random information display” employs unidirectionally aligned NR films as a projection screen to display any information coded by a LC cell. It is also shown that the NR/LCP composite film can align LC in bulk, and therefore, can be integrated into a LC cell, fabricating a robust photoemissive NR display device.