Significant Enhancement of Circular Polarization in Light Emission through Controlling Helical Pitches of Semiconductor Nanohelices.

Ni, Ziyue; Qin, Ping; Liu, Hongshuai; Chen, Jiafei; Cai, Siyuan; Tang, Wenying; Xiao, Hui; Wang, Chen et al. · ACS Nano · 2023

basic_science · Level V

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Abstract

Circularly polarized light emission (CPLE) can be potentially applied to three-dimensional displays, information storage, and biometry. However, these applications are practically limited by a low purity of circular polarization, i.e., the small optical dissymmetry factor <i>g</i><sub>CPLE</sub>. Herein, glancing angle deposition (GLAD) is performed to produce inorganic nanohelices (NHs) to generate CPLE with large <i>g</i><sub>CPLE</sub> values. CdSe NHs emit red CPLE with <i>g</i><sub>CPLE</sub> = 0.15 at a helical pitch (<i>P</i>) ≈ 570 nm, having a 40-fold amplification of <i>g</i><sub>CPLE</sub> compared to that at <i>P</i> ≈ 160 nm. Ceria NHs emit ultraviolet-blue CPLE with <i>g</i><sub>CPLE</sub> ≈ 0.06 at <i>P</i> ≈ 830 nm, with a 10<sup>3</sup>-fold amplification compared to that at <i>P</i> ≈ 110 nm. Both the photoluminescence and scattering among the close-packed NHs complicatedly account for the large <i>g</i><sub>CPLE</sub> values, as revealed by the numerical simulations. The GLAD-based NH-fabrication platform is devised to generate CPLE with engineerable color and large <i>g</i><sub>CPLE</sub> = 10<sup>-2</sup>-10<sup>-1</sup>, shedding light on the commercialization of CPLE devices.