Composites of Silver Nanoclusters and Cellulose Nanocrystals with Tunable Emission as Multicolor Inks

Abstract

Here, we report fluorescent films of silver nanoclusters (AgNCs), polyvinylpyrrolidone (PVP), and photonic cellulose nanocrystals (CNCs) with a tunable fluorescence emission color by an evaporation-induced self-coassembly route. The AgNC x -CNC films with a low AgNC loading display a red structural color, in which the chiral nematic structures of the CNCs are preserved. The typical film of AgNC 6 -CNCs exhibits a negative circularly polarized luminescence signal because of the photonic band gap effect, and the glum value at 650 nm reaches −0.12. The AgNC-CNC films show promising anticounterfeiting potential for their humidity responsiveness. Additionally, the AgNCs show changes in emission color in response to the pH of the medium, which is attributed to the pH influencing the electron transfer from the ligands to the metal core through Ag−S bonds and the size of AgNCs. Furthermore, the suspension of AgNC-CNCs at different pH values is stable enough, which can be used as a multicolor fluorescent ink to write on paper to obtain photoluminescent patterns with different colors.

Polymer‐Based Circularly Polarized Luminescent Materials

“…[172] In another work, Yang et al fabricated fluorescent films by evaporation-induced co-assembly of CNCs, silver nanoclusters, and polyvinylpyrrolidone. [173] The films could exhibit a negative CPL signal due to the PBG effect, and g lum value could reach −0.12.…”

“…[176] This strategy could achieve the generation of CPLactive polyfluorene aggregate by completely removing dialkylpolysilane. The authors found that the resulting heteroaggregates might be composed of one polyfluorene chain and two Fluorescent organic dyes Solid film -0.68 [16] Fluorescent organic dyes Solid film -0.28 [157] Polyacetylene Solid film -0.65 [155] Quinine sulfate Solid film 38% 0.58 [149] Quinine sulfate dihydrate Solid film -0.51 [154] PEI Solid film -0.025 [156] CdSe/CdS quantum rods Solid film -0.45 [148] ZnS/CdSe quantum dots Solid film -0.48 [158] ZnS/CdSe quantum dots Solid film -0.84 [159] Silicon quantum dots Solid film -0.25 [160] Carbon dots Solid film 30.22% 0.74 [161] Carbon dots Aqueous dispersions -0.2 [162] Carbon dots Solid film 5.2% 0.27 [163] Carbon dots Solid film 2.8% 0.66 [164] Carbon dots Solid film -1.47 [165] Upconverting nanoparticles Solid film -0.156 [166] Lanthanide complexes Solid film 66.7% 0.36 [167] Perovskite nanocrystals Solid film 43.1% 0.057 [168] Gold nanoclusters Solid film -0.287 [172] Silver nanoclusters Solid film 15.96% 0.12 [173] NaGdF4Yb 3+ , Er 3+ @ Carbon dots Solid film -0.84 [152] polysilanes chains. Wei et al described the preparation of polyether-based cholesteric liquid crystalline copolymers containing chiral cholesteryl, cross-linkable allyl, as well as, cyano-biphenyl mesogenic groups moieties by anionic ring-opening polymerization.…”

Responsive Chiral Photonic Cellulose Nanocrystal Materials

“…assembled CNCs, silver nanocluster (AgNCs), and PVP, yielding tunable luminescence in response to humidity and solvents. [ 183 ] The luminescence quenched progressively upon exposure to 90% RH, exhibiting progressively decreased luminescent intensity as a function of exposure time. In addition, the luminescent intensity of the composite film gradually enhanced as the ethanol content in water increased from 0% to 100%.…”

Porphyrin Photosensitizers Grafted in Cellulose Supports: A Review

“…From this disintegration, either cellulose nanofibers (CNF) or nanocrystalline cellulose (NCC) can be obtained, the latter also known as cellulose nanocrystals (CNCs). These CNCs possess unique properties, such as high surface area, high mechanical strength, and a liquid crystalline nature [ 14 , 15 , 16 , 17 ] with applications in several fields, such as biomedicine [ 18 , 19 ], wastewater treatment [ 20 , 21 ], biobased adsorbents of metals [ 22 , 23 , 24 ], energy [ 25 , 26 ], and photonic platforms [ 27 , 28 ].…”