Circularly polarized light emission (CPLE) can be potentially applied to three-dimensional display, information storage and biometry. However, these applications are practically limited by low purity of circular polarization, i.e., small optical dissymmetry factor (which has the maximum value of 2).
Prof. Zhifeng HUANG led a collaborative team to produce inorganic nanohelices (NHs), using glancing angle deposition (GLAD), for generating CPLE with large values. Cadmium selenide (CdSe) NHs emit red CPLE with of 0.15 at a helical pitch (P) of ≈570 nm, having a 40-fold amplification of compared to that at a P of ≈160 nm. Ceria NHs emit ultraviolet–blue CPLE with of ≈0.06 at a P of ≈830 nm, with a 103-fold amplification compared to that at a P of ≈110 nm. Both the photoluminescence and scattering among the close-packed NHs complicatedly accounts for the large values, revealed by the numerical simulations. For comparison, organic chiral molecules generally have a value in a range of 10-5–10-3. Prof. HUANG’s team devised the GLAD-based NH-fabrication platform to generate CPLE with engineerable color and high purity of circular polarization ( of 10-2–10-1), shading light on the commercialization of CPLE devices. This work was published by ACS Nano, https://pubs.acs.org/doi/10.1021/acsnano.3c07663.