Electrospun perovskite quantum dots-based Janus microribbons film with white light and multicolor luminescence for optical data storage and anti-counterfeiting.

In order to attain white light or multicolor luminescence of perovskite quantum dots (PQDs) materials, the prevalent method involves directly blending PQDs with different type and composition of halogen anions. However, this method allows uncontrolled halogen anion exchange between the different PQDs, thereby leading to alterations in the final fluorescence color of the material. To address this problem, we creatively design and fabricate a PQDs-based Janus microribbons film (Janus-MRF) with white light emission and multicolor fluorescence under multi-wavelength stimulation by a parallel electrospinning. [CsPbClBr/Eu(BA)phen/PS]//[CsPbBr/Eu(BA)phen/PS] (BA = benzoate radical, phen = 1,10-phenanthroline, PS = polystyrene) Janus microribbon (Janus-MR) serves as fundamental structural unit of Janus-MRF, CsPbClBr and CsPbBr PQDs respectively provide blue and green fluorescence, and Eu(BA)phen offers red fluorescence. The introduction of Janus structure in Janus-MR allows the interior of the Janus-MR to form two independent microscopic domains, confining CsPbClBr PQDs and CsPbBr PQDs to their respective domains and avoiding halogen anion exchange caused by direct contact between the two PQDs and obtaining superior and designed macroscopic fluorescence. Owing to the disparity in optimal excitation wavelengths between PQDs and Eu(BA)phen, white light and multicolor emissions of Janus-MRF can be achieved under multi-wavelength stimulation. Furthermore, the fluorescent color of Janus-MRF is sensitive to temperature changes. As an applicative demonstration of Janus-MRF, different sub-barcodes are obtained by using the identifiable fluorescence spectra emitted by Janus-MRF under multi-wavelength stimulation and the sensitivity of fluorescent color of Janus-MRF to temperature changes, and further these sub-barcodes are integrated into the large photonic barcodes encoding library for high-volume data storage and advanced anti-counterfeiting applications. This work provides a novel idea and strategy for advancing fabrication and application of materials based on PQDs.