Quantum dot particles for linearly polarized LCD backlights

Semiconductor quantum dots can provide narrow-band photoluminescence with dominant wavelength determined by the size of the quantum dots. Core-shell particles with an elongated shell that are aligned with each other, can yield linearly polarized red or green light by down-conversion of blue. The shell typically has a larger band gap that effectively absorbs the photons emitted by a blue LED. The electron-hole pair is transferred to the quantum dot core, which has a smaller band gap than the shell. The semiconductor particle with the embedded quantum dot can be aligned by an electric field when it is dispersed in a non-polar solvent or in liquid crystal. After polymerization a thin film is observed with provides linearly polarized light. By aligning this layer with the direction of transmission of the polarizer of an LCD panel, the losses in the polarizer can be reduced considerably. Based on this approach an LCD with highly saturated red and blue colors and low losses in the polarizers should become a possibility.

Publication year:2018

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