Integrating chromophores into chiral photonic crystals to fabricate materials that exhibit circularly polarized luminescence (CPL) is promising as this method allows efficient manipulation of the spontaneous emission within photonic bandgaps (PBGs). However, tuning the wavelength of CPL and the dissymmetry factor (g lum) in a convenient and accurate manner remains a significant challenge. Here, right-handed, tunable upconverted CPL (UC-CPL) emission was achieved by integrating multiple emissive, upconverting nanoparticles into cellulose nanocrystal based chiral photonic films that had tunable PBGs. Glycerol was used to tune the PBGs of the chiral photonic films, which yielded tunable UC-CPL emission at 450 and 620 nm with a tailored g lum. Moreover, humidity responsive UC-CPL at blue wavelength was obtained from glycerol-composite photonic film, with a g lum that ranged from −0.156 to −0.033. It was possible because the PBG and chirality of photonic composite was responded to the relative humidity. This work gives valuable insight into tunable and stimuli-responsive CPL photonic systems.

Sustainable carbon dots (CDs) based on furfuraldehyde (F-CD) resulted in a photosensitive material after pursuing the Alder-Longo reaction. The porphyrin moiety formed connects the F-CDs in a covalent organic network. This heterogeneous material (P-CD) was characterized by XPS indicating incorporation of the respective C, N and O moieties. Time resolved fluorescence including global analysis showed contribution of three linked components to the overall dynamics of the excited state. Electrochemical and photonic properties of this heterogeneous material facilitated photopolymerization in a photo-ATRP setup where either CuBr 2 /TPMA, FeBr 3 /Br À or a metal free reaction setup activated controlled polymerization. Chain extension experiments worked in all three cases showing end group fidelity for activation of controlled block copolymerization using MMA and styrene as monomers. Traditional radical polymerization using a diaryl iodonium salt as co-initiator failed.

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.

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Near-infrared (NIR) light is an ideal source for initiating polymerization because of the lower energy of NIR photons and considering that NIR light usually has deeper penetration depth in materials than UV light. Recently, lanthanide-doped upconverting nanoparticles (UCNPs) were used for NIR photopolymerization. UCNPs convert NIR light to UV or visible light, which can subsequently be absorbed by photosensitizers or photo-initiators. Subsequently, the excited photosensitizers/photoinitiators trigger polymerization. This process is referred to UCNP-assisted photopolymerization. Herein, recent progress in UCNP-assisted photopolymerization is introduced, applications of materials prepared via this type of reaction are highlighted, and the associated challenges are discussed.[a] Prof.