Highly Polarized Fluorescent Film Based on Aligned Quantum Rods by Contact Ink-Jet Printing Method

Fluorescent quantum rods (QRs) have received much attention recently because of their properties of polarized light emission with narrow full width at half-maximum. Therefore, QRs can be used in liquid crystal display (LCD) backlight, as an active polarizer. In order to emit light with a high degree of polarization (DOP), QRs need to be controlled and aligned along one direction on large-scaled devices. However, most of the proposed effective alignment approaches cannot be applied to a large area. In this paper, we report for the first time the contact ink-jet printing (CIJP) method to align CdSe/CdS core/shell QRs. With the ink being printed, the QRs can align along the fluid ink flow direction resulting in aligned QRs along printing direction and forming a film with a high DOP of 42%. Furthermore, CIJP can realize arbitrarily large area fabrication without reducing DOP value. It is expected that this method can be utilized to print on large-scaled substrates directly to fabricate polarized optoelectronic devices, and further applied to LCD backlights and any other applications where polarized light is needed.