Multi-responsive CPL switches of carbon dots confined in chiral metal–organic frameworks

Abstract

Solid-state stimuli-responsive circularly polarized luminescent (CPL) materials hold significant potential for applications in 3D displays, multi-level encryption, and chiroptical devices. However, research on CPL switching in solid-state carbon dots (CDs) remains unexplored. Herein, we construct photo-switchable solid-state CD based CPL-active assemblies by simultaneously encapsulating both CDs and spiropyran (SP) into chiral metal–organic frameworks (CMOFs) as the host. It is found that the SP units in the CMOF@CD/SP assemblies exhibit a colorless closed-ring state and a blue open-ring state under alternating ultraviolet (UV) and visible light irradiation, which regulates the inactivation and activation of the photochromic fluorescence resonance energy transfer (FRET) process, respectively, between the CDs and the SP units, thereby enabling reversible photoswitching of both photoluminescence (PL) and CPL properties. Leveraging these reversible CPL switching properties, the assemblies are successfully applied to high-security 3D barcodes, chiral logic gates, and 3D printing for the first time, providing innovative solutions for information security and logic computing.