Helical Stacking Assembly of Orderly Silicon Nanowire Multilayers for Ultrastrong Dissymmetrical Amplification of Circularly Polarized Light

Abstract

AbstractCircularly polarized organic light‐emitting diodes (CP‐OLEDs) are ideal candidates to explore novel applications such as 3D displays, optical storage, and quantum computing. However, the low dissymmetry (g) factor of most chiral organic materials remains as a major challenge for practical applications. In this work, a helical stacking assembly of orderly silicon nanowires (hs‐SiNWs) into a flexible multilayer 3D superstructure is demonstrated to accomplish a strong chiroptical activity. These orderly SiNWs are batch‐fabricated via a low temperature in‐plane solid–liquid–solid growth mechanism, with precisely‐controlled spatial arrangement and mean diameter and length of Dnw = 126 ± 24 nm and Lnw > 100 µm, respectively. To construct such helically‐stacked superstructure, the SiNW arrays are transferred and stacked upon transparent glass or flexible polymer substrates, with incremental rotational angle for each layer, which can strongly augment the circularly polarized electroluminescence (CPEL) from conventional CP‐OLEDs. Strikingly, the dissymmetry factor increases with more stacking layer up to g = ±0.17, which is more than 40 times of magnitude higher than that of the original CPEL, among the highest ones reported for CP‐OLEDs. These results indicate a promising helical‐stacking avenue to boost the chiroptical performance of various CP‐OLEDs for scalable and flexible chiroptical applications.