Multicolor chiral perovskite nanowire films with strong and tailorable circularly polarized luminescence

Abstract

Perovskites showcased potential promise for innovative circularly polarized luminescence (CPL)-active multichannel information encryption, owing to the exceptional luminescence brightness. It was still a formidable challenge to fabricate CPL-active perovskites with significant luminescent asymmetry factor (g_lum) and full-colour-tailorable CPL properties. Indeed, compared to isotropic perovskites, anisotropic perovskite nanowires (NWs) were conducive to carrier separation and transport for polarization enhancement. Herein, three types of CsPb(Br/I)₃ NWs with green, orange, red fluorescence (FL) were respectively synthesized and assembled into chiral NW films. The right-handed/left-handed chiral NW films constructed by 4+4 layers and 45° inter-angles exhibits highly symmetric and mirror-like chiral signals. The strongest chiral intensity is more than 3000 medg. CPL signals with wide colour gamut produce ranging from 480 ​nm to 800 ​nm, and tailorable CPL wavelengths are manipulated by the emission wavelength of perovskite NWs. A giant CPL signal with a maximum g_lum of up to 10⁻¹ is achieved. The polarization imaging of chiral NW films produces brilliant differential circularly polarized structural colours, making it more widely used in multilevel anti-counterfeiting systems. A significant breakthrough lies in the development of advanced chiral perovskite materials with remarkable g_lum and tailorable CPL properties, which sheds new light on optical anti-counterfeiting and intelligent information encryption.