UV-Filtering Cellulose Nanocrystal/Carbon Quantum Dot Composite Films for Light Conversion in Glass Windows

Abstract

The development of energy-saving materials in buildings based on biomass materials is a general consensus building construction of low-carbon cities. Herein, we reported an effective ultraviolet (UV)-filtered film, composed of carbon quantum dots (CDs) and cellulose nanocrystals (CNC). The results showed that CNC had nanoscale dimensions with a diameter of 20−50 nm and length of 250−450 nm, a high crystallinity index of 84.7%, and enrichment of hydrogen bonds on the surface. The photoluminescence spectra showed that ligninbased carbon quantum dots (CDs) exhibited a long-wavelength red emission (623 nm) and an uncommon narrow emission bandwidth (fwhm <30 nm). In addition, the prepared UV-filtered film had strong mechanical tensile properties, good UV light absorbing capability, and water resistance. The optical test showed that the film also had highly optical transparency (94%) and haze (70%). The excellent light management and conversion function of this film provides a new user experience for soft, uniform, healthy, and comfortable indoor sunlight lighting.

One-Step Hydrothermal Synthesis of Nitrogen-Doped Carbonized Polymer Dots with Full-Band Absorption for Skin Protection

“…Long-term and excessive ultraviolet (UV) radiation will slow down the growth of plants or even cause early apoptosis, paint fading, and fresco peeling phenomenon, significantly affecting people’s health. , High doses of UV radiation will accelerate skin aging, cause local skin redness, pain, itching, peeling, and other symptoms, resulting in pigmentation, which in turn gives rise to sunspots, freckles, and so forth, and may even trigger skin cancer, solar dermatitis, cataracts, and other diseases. − In the solar spectrum, UV radiation is classified into UVA (320–400 nm), UVB (280–320 nm), and UVC (200–280 nm) . The highest energy and most harmful UVC radiation gets blocked by the ozone layer in the atmosphere so that it fails to reach the Earth’s surface, and it is mainly UVB radiation and UVA radiation that cause the most significant damage to human health .…”

Red-Emissive Sulfur-Doped Carbon Dots for Selective and Sensitive Detection of Mercury (II) Ion and Glutathione

“…However, the extreme hydrophobicity and low fluorescence quantum yield of porphyrins greatly limited their applications in bioimaging and cancer therapy [ 25 , 26 ]. Considering the large π-π conjugated structure [ 27 ], high thermal stability [ 28 ], and red fluorescence of porphyrin molecules [ 29 ], the porphyrins with functional groups, such as hydroxyl, carboxyl, and amino groups, should be the potential precursors for the preparation of red-emissive RCDs.…”

Synthesis of Carbon Dots with Carbogenic π-Conjugated Domains for Full-Band UV Shielding

“…More importantly, CDs are regarded as the most promising alternative to commercial UV absorber for absorption of UV rays and chemically inert . In the last few years, the usage of CDs as UV absorbers has been increasingly reported; for example, organic molecules such as citric acid are used as a carbon source for the hydrothermal synthesis of CDs for UV shielding. − Biomass carbon dots (CDs) from renewable materials have also been successfully used for UV absorption. ,, However, the reported CDs have relatively low UV shielding rates and narrow-band UV shielding and usually produce absorption only in a single region of UVA or UVB, which may necessitate their use in combination with nano ZnO or organic chemical UV absorbers. , High-efficiency CD ultraviolet absorbers that can absorb over the entire ultraviolet range have rarely been reported thus far. Therefore, it is essential to explore more new UV blocking materials with high stability and outstanding all-waveband UV blocking behavior.…”

“…15−21 Biomass carbon dots (CDs) from renewable materials have also been successfully used for UV absorption. 7,22,23 However, the reported CDs have relatively low UV shielding rates and narrow-band UV shielding and usually produce absorption only in a single region of UVA or UVB, which may necessitate their use in combination with nano ZnO or organic chemical UV absorbers. 24,25 High-efficiency CD ultraviolet absorbers that can absorb over the entire ultraviolet range have rarely been reported thus far.…”