Chiral electroluminescence from thin-film devices based on momentum-space engineering

Abstract

Chiral light sources are important for various applications including 3D displays, optical recording, optical communication, bioimaging, and biomedical diagnosis. Among others, CP light sources based on perovskite materials are attracting considerable attention to fully exploit their exceptional optoelectronic properties. Recently, there has been extensive research for achieving CP photoluminescence from perovskite materials. However, there was no demonstration of CP electroluminescence (EL) yet with a substantial degree of circular polarization (DCP), although it represents a critical step toward practical device applications. In this talk, I present a recent experimental work from our group. We experimentally achieved chiral EL with a substantial DCP (~0.38) using momentum-space engineering. Although various three-dimensional and two-dimensional chiral nanostructures have been studied and engineered in real space, strong chiral optical responses can also be obtained in momentum space. In our design, a periodic lattice of inversion-symmetry-broken polycrystalline silicon (poly-Si) patterns is integrated with an inorganic perovskite (CsPbBr3) EL device. The bottom poly-Si layer and top metal layer forms a photonic cavity. In our device, a pair of left circularly polarized (LCP) and right circularly polarized (RCP) EL is split into two opposite directions with equal power. Because many chiral applications require both LCP and RCP light sources, our design may be desirable for various applications requiring the compact chiral light sources.