Circularly Polarized Room-Temperature Phosphorescence with an Ultrahigh Dissymmetry Factor from Carbonized Polymer Dots by Stacked Chiral Photonic Films

Abstract

Developing circularly polarized room-temperature phosphorescent (CPRTP) materials with a high dissymmetry factor (g lum) and long afterglow is very attractive but highly challenging. Here, a CPRTP emission featuring ultrahigh g lum value and desired visualization characteristic in a bilayer composite photonic film is achieved for the first time. In the constructed system, N and P co-doped carbonized polymer dots (NP-CPDs) are dispersed into polyvinyl alcohol (PVA) as the phosphorescent emitting layer, and helically structured cholesteric polymer films are used as selective reflective layers to convert the unpolarized emission of NP-CPDs into circularly polarized emission. On the basis of the modulation of the helical structure period of the cholesteric polymer, the bilayer composite film enables NP-CPDs to obtain a high g lum value. Notably, the optimized photonic film emits CPRTP with g lum as high as 1.09 and a green afterglow lasting above 8.0 s. Moreover, the composite photonic array films featuring information encryption characteristics are developed by modulating the liquid crystal phase of the cholesteric polymer film and the dot coating position of the NP-CPDs/PVA layer, thus expanding the application of CPRTP materials in cryptography and anti-counterfeiting.

Symmetry‐Triggered Tunable Phosphorescence Lifetime of Graphene Quantum Dots in a Solid State

“…d) Comparison of the phosphorescence lifetime and phosphorescent emission wavelength of carbon nanostructures from the recently reported literature. [ 17,23–67 ] e) Photographs of SN‐GQDs and BN‐GQD powders at different times after radiation by the UV light (365 nm) for 0.5 min. f) Phosphorescence decay curve of SN‐GQDs.…”

Circularly polarized luminescence in quantum dot-based materials

“…Guo and co-workers constructed a bilayer photonic architecture with CPRTP emission featuring an ultrahigh g lum value and long afterglow. 183 In this bilayer structure, carbon QDs/ PVA were used as a phosphorescent emitting layer and a cholesterol-based polymer film was used as a selective reflective layer. The g lum value of the bilayer composite film could reach 1.09 by adjusting the helical structure period of the cholesteric polymer.…”

Colloidal Chiral Carbon Dots: An Emerging System for Chiroptical Applications

“…Imaging [ 87] CDots Chiral solvent limonene -Imaging [ 88] CDots cholesteric liquid crystal g RTP = 1.09 circularly polarized room-temperature phosphorescent imaging [ 89] Tyrosine: Pro: Proline; Phe: phenylalanine; Cys: Cysteine; Gln: Glutamine; His: Histidine; Arg: Arginine; Glu: glutamic acid; lum: Luminescence; RTP: room-temperature phosphorescence; Asp: L-aspartic acid; Trp: tryptotophan; Thr: Threonine; GSH: Glutathione which is ac-CDots. The helical pitch of chiral hybrid films was varied from 420 to 740 nm regulated by the CNCs/PVA ratio.…”