Structural materials with afterglow room temperature phosphorescence activated by lignin oxidation

Abstract

Sustainable afterglow room temperature phosphorescence (RTP) materials, especially afterglow RTP structural materials, are crucial but remain difficult to achieve. Here, an oxidation strategy is developed to convert lignin to afterglow materials with a lifetime of ~ 408 ms. Specifically, lignin is oxidized to give aromatic chromophores and fatty acids using H2O2. The aromatic chromophores are locked by a fatty acid-based matrix by hydrogen bonds, triggering enhanced spin orbit coupling and long afterglow emission. More interestingly, motivated by this discovery, an auto fabrication line is built to convert wood (natural structural materials) to wood with afterglow RTP emission (RTP wood) via in situ oxidation of naturally-occurring lignin located in the wood cell walls to oxidized lignin (OL). The as-prepared RTP wood exhibits great potential for the construction of sustainable afterglow furniture. With this research we provide a new strategy to promote the sustainability of afterglow RTP materials and structural materials.

Room temperature phosphorescence from natural wood activated by external chloride anion treatment

“…The first approach relies on converting biomass materials (such as, gelatin, cellulose and rice husks) to carbon dots endowed with efficient SOC; these dots are then confined in an organic matrix to stabilize the triplet excitons 19 – 21 . Another strategy involves using directly untreated natural materials, such as lignin, gelatin and cellulose, as chromophores incorporated within a rigid matrix 22 – 25 . However, the fabrication of these sustainable RTP systems generally involves the use of toxic reagents, energy-consuming processes, or complex procedures that are difficult to carry out on large scale.…”

“…However, the fabrication of these sustainable RTP systems generally involves the use of toxic reagents, energy-consuming processes, or complex procedures that are difficult to carry out on large scale. For example, from our previous research we converted wood to structural RTP materials using lignin oxidation assisted by NaOH and concentrated H 2 O 2 25 . However, drying the concentrated H 2 O 2 -incoporated wood in the oven at high temperatures is very dangerous (potentially explosive).…”

“…To address the above challenge, we were drawn to wood. Wood is a largely renewable resource that exhibits short phosphorescence (~17–30 ms), a result attributed to the confinement of lignin within the associated cellulose and hemicellulose matrix 25 , 30 , 31 . Previous reports have indicated that the lifetime of phosphorescent chromophores can be enhanced by treating with heavy atom salts 32 – 34 , certain small molecules 35 – 39 or polymers 40 – 42 .…”

Fabrication of Carboxylic Acid and Imidazolium Ionic Liquid Functionalized Porous Cellulosic Materials for the Efficient Conversion of Carbon Dioxide into Cyclic Carbonates

“…Conversion of biomass into high value-added chemicals and sustainable materials has become a hot topic, − among which the design and preparation of cellulose-PILs have received great attention. The preparation of cellulose-PILs is mainly achieved by reaction of cellulose’s hydroxyl groups.…”

Solvent effect on the production of spherical lignin nanoparticles

“…[8][9][10][11] Another way is directly using the macromolecular lignin as a precursor to construct materials. [12][13][14] This approach maximumly utilizes the inherent structural features of lignin with reducing the energy input for cleavage of chemical bonds and elimination of the exhausted product separation procedures. For example, owing to the benzene rings and oxygencontaining functional groups in lignin, they can self-assemble into spherical lignin nanoparticles (LNPs) with hydrophobic cores and hydrophilic shells through π-π stacking of the benzene rings.…”