UV Light Filters Research Articles

Innovative Photoprotection Strategy: Development of 2-(Benzoxazol-2-Yl)[(2-Hydroxynaphthyl)Diazenyl] Phenol Derivatives for Comprehensive Absorption of UVB, UVA, and Blue Light.

Overexposure to blue light due to the excessive use of electronic devices has been implicated in premature skin aging and eye damage, among other injuries to health. This study aimed to synthesize two azo derivatives of the 2-(amino-2'-hydroxyphenyl) benzoxazole and explore their potential as UV and blue light filters, proposing a new spectral profile. The synthesis of the heterocyclic compounds involved condensation reactions and diazotation. The derivatives 2-(benzoxazol-2-yl)-5-[(2-hydroxynaphthyl)diazenyl]phenol and 2-(benzoxazol-2-yl)-4-[(2-hydroxynaphthyl)diazenyl]phenol were synthesized with a yield greater than 70%. Solubility was evaluated in seven different solvents. The maximum absorption wavelengths (λmax) were determined using UV-Vis scanning spectrophotometry in the range of 200-600 nm. Photostability was assessed using a solar simulator and the Sun protection factor (SPF) was determined using invitro methodology. Cytotoxicity was evaluated using the MTT assay in V79 cells. These compounds were able to absorb UVA, UVB, and blue light, with λmax ranging from 300 to 500 nm and demonstrated photostability after 3 h of exposure to solar simulator with an SPF higher than 45. The compounds exhibited solubility in all lipophilic solvents tested. Regarding cytotoxicity, IC50 values were comparable to other filters. These findings indicate that both compounds hold promise as potential organic filters.

Cyanopyridone doped PMMA films as UV and blue light filters: Preparation and characterization

Cyanopyridone-based conjugated small molecule (CP) doped poly(methyl 2-methylpropenoate) polymeric films were obtained using solvent-casting approach with various concentrations of CP loading ranging from 1 to 6 wt%. Further, structure and linear absorption properties of the prepared polymeric films were investigated in detail. Structural characterizations of polymeric films were carried out using XRD technique, where an amorphous hump was noticed which indicates the non-crystalline nature of examined polymeric composites. Spectral assessment of the films like absorbance and transmittance were made by using spectrophotometer in the wavelength (λ) region ranging from 200 to 1100 nm and followed by the determinations of absorption index (k), as well as optical energy band gap (Eg). Results revealed that the optical constants vary with the amount of CP loading and also, these polymeric composite films effectively blocks nearly 94 % of UV and blue light transmission and hence these films can be used in the UV and blue region filters.

Design and optimization of nanostructured UV-filters for efficient and stable perovskite solar cells

The design and optimization of nanostructured UV-light filters, for perovskite solar cells (PSCs), using the COMSOL Multiphysics commercial package is performed. This design is crucial for severe instability issues found in the degradation of perovskite materials under UV-light illumination. The suggested structure is a thin film of TiO2 in conjunction with nanoparticles layers of TiO2, WO3, and ZnO. It is noted that the most efficient structure is a 10 nm TiO2 thin film under a 50 nm bi-composite layer of TiO2 and WO3 nanoparticles. The proposed structure significantly improves the stability of PSCs in the UV-light region, where the UV-blocking properties are enhanced by about 75% compared with a solar cell without using the suggested filter design.

Forensic Photography: A Visual and Legal Record of Crime Scene

Based on priority forensic photography is a source of documenting crime scenes. Currently it enables to signify a crime scene with every significant pieces of location and evidences. Adding to forensic investigation, crime scene photography provides a true and precise record of original scene and evidences relevant to surroundings. Crime scene photograph can illustrate a crime scene easily than verbal description by an investigator as it freezes time and records the evidences. It records all type of crime scenes such as fingerprints, impressions, injuries or bruises on skin in assault cases, human identification, bloodied body and knife in murder case etc. Scientific photography skills and techniques such as UV, IR and Fluorescence light filters are practiced to discover and preserve the hidden information during investigation. It is an integral part of criminal investigation by providing proper documented focused photographs to present actual story of the scene in the courtroom.

Reprecipitation induced isolation of ligand-free Cs4PbBr6 nanodisks as a green emissive UV light filter

A strong green emissive UV shielding polymer film has been prepared by incorporating different weight fraction of ligand-free Cs4PbBr6 nanodisks into a polymer matrix. A routine reprecipitation method is introduced to isolate ligand-free Cs4PbBr6 nanodisks for better dispersion in a polymer matrix. As-prepared polymer film shows an excellent UV shielding with increasing content of ligand-free Cs4PbBr6 nanodisks. About 30% of UV shielding was observed with 7.5 mg of ligand-free Cs4PbBr6 nanodisks, while the maximum UV shielding of 80 and 83% was witnessed in a polymer film containing 25 mg of ligand-free Cs4PbBr6 nanodisks under a UV lamp and direct daylight sources, respectively. The UV-shielding capability of polymer film was further verified by testing of UV light induced rhodamine B degradation and compared to pure polymer film. Furthermore, due to a down-conversion of ligand-free Cs4PbBr6 nanodisks, a strong green emission was observed of converting high energy UV radiation into green emission, upon illumination of UV light. Thus, the development of green emissive UV shielding polymer film can be recommended to use as a packaging film, emulsion, paints and protective coating etc.

Growth and characterization of ammonium nickel-copper sulfate hexahydrate: A new crystal of Tutton's salt family for the application in solar-blind technology

We have obtained the mixed crystals ammonium nickel-copper sulfate hexahydrate compounds which exhibits 98% transmittance in the ultraviolet region, a promising material for UV light filters and UV sensors for solar-blind technology. These crystals belong to the family of Tutton's salt having empirical formula (NH4)2NixCu(1-x) (SO4)2.6H2O and they were synthesized by employing growth from the slow evaporation of aqueous solution technique. The crystallographic parameters, three-dimensional Hirshfeld surface analysis and the calculation of two-dimensional fingerprint plots of the sample crystal (NH4)2Cu(SO4)2.6H2O were determined with the help of single crystal X-Ray diffraction. The X-ray powder diffraction of the pulverized samples were carried out at ambient temperature, 200 °C and 350 °C with the purpose to observe the change in the crystalline structure when subjected to higher temperatures. The thermal analysis of the samples was conducted in the temperature range 30–900 °C with the help of thermogravimetric analysis (TGA), which provides the information about the thermal stability and decomposition process during the heat treatment. Some of our sample crystals demonstrated high dehydration temperature up to 108 °C and they can be considered as an excellent candidate for UV light filters for high temperature applications. The direct and indirect band gaps of the samples were determined from UV–Vis spectra with the help of Tauc's equation. The overtones and combinations of fundamental vibrations of the functional groups our sample crystals were investigated by utilizing near-infrared spectroscopy in the wavelength range 830–2500 nm.

Growth and characterization of ammonium nickel-cobalt sulfate Tutton’s salt for UV light applications

We have obtained a set of sample crystals of the family of Tutton’s salt comprise in the isomorphic series with general chemical formula (NH4)2NixCo(1−x) (SO4)2·6H2O, by employing growth from solutions by slow evaporation technique. The samples crystals were characterized by ICP-AES, X-ray powder diffraction analysis, thermogravimetric analysis, UV–Vis-NIR, Raman and FTIR spectroscopy. This type of material has been studied because of its physical and chemical properties not yet understood and they have potential technological applications. Chemical analysis of the samples by ICP-AES method allowed us to investigate the efficiency of the method of growth used. Thermogravimetric analysis provides the information about the thermal stability of the obtained crystals for high temperature applications, and powder X-ray diffraction analysis at ambient and high temperature reveals the structural quality and structural change of the samples respectively. We have used Raman spectroscopy in the range 100–4000 cm−1 and FTIR spectroscopy in the range 400–4000 cm−1 to understand the internal vibrational mode of the octahedral complexes [Ni(H2O)6]2+ and [Co(H2O)6]2+, SO42− and NH4+ tetrahedra. The transmittance of our mixed ammonium nickel cobalt sulfate hexahydrate (ACNSH) crystals is 75% in the UV region, which indicates that they are ideal to use in UV light filters and UV sensors.

Growth and characterization of potassium cobalt nickel sulfate hexahydrate crystals: A new UV light filter

Abstract Samples of the empirical formula K 2 + N i x 2 + C o 1 − x 2 + S O 4 2 ⋅ 6 H 2 O were grown with a partial occupation of the cations Co and Ni. Mixed crystals with good optical quality were obtained by the slow evaporation growth method. In the decomposition process, these crystals suffer a mass loss of approximately 24%, equivalent to water molecules forming octahedral coordination ions of Ni and Co. The optical characteristics of the grown crystals were measured where transmittance reached more than 80% in the wavelength range of 190–390 nm. By Raman spectroscopy, the vibrational modes of SO 4 2 − , H2O and of the octahedral Ni(H2O)6 and Co(H2O)6 were identified.

Structures, Photophysical Properties, and Growth Patterns of Methylurea Coordinated Ni(II) and Mn(II) Complexes

Four coordinated complexes MnxNi(1−x)(C2H6N2O)6SO4 (x=0, 0.33, 0.75, 0.90) were synthesized and characterized. Single-crystal X-ray analysis revealed that the complexes belong to the trigonal crystal family, R-3c space group. Spiral and terraced nucleus growth modes were observed by atomic force microscopy (AFM) in the crystals. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) measurements showed their excellent thermostability until 200 °C. UV–vis spectra revealed that the transmission peaks of these crystals have a slight bathochromic shift compared to nickel sulfate hexahydrate (NSH), and the transmittance in the UV range increased as the proportion of Mn2+ increased. With their photophysical properties remaining similar, the much higher heat endurance is rendering these crystals better suitable for UV light filter (ULF) applications.

Surfactant-free synthesis of leaf-like hierarchical CuO nanosheets as a UV light filter

The present investigation reports a simple solution process for synthesizing the leaf-like hierarchical CuO nanosheets without using a surfactant/template at low temperature. The crystalline structure, morphology and the UV light absorption capability of leaf-like hierarchical CuO nanosheets were examined. The UV light absorption capability was estimated by dispersing few percentage of leaf-like CuO nanosheets in a polymer film. An excellent UV light absorption capability was witnessed in a polymer film containing 0.2% of leaf-like CuO nanosheets with the maximum of 68% and 66% under a UV lamp and the direct daylight sources, respectively.

Design and analysis of processing parameters of hololenses for wavelength selective light filters

In this communication the spectral characteristics based on diffraction efficiencies of hololenses in reconstructions at Bragg's angles for a wide range of wavelengths is presented. By properly optimizing design parameters of hololenses, their spectral characteristics can be controlled in the desired wavelength range. Creation of UV, visible and IR light filters have been presented in this manuscript through simulation and to validate the theoretical predictions, an experimental curve has been plotted with available wavelength sources and is found to be in good agreement.

Effects of blue light–filtering intraocular lenses on the macula, contrast sensitivity, and color vision after a long-term follow-up

To evaluate the possible side effects and potential protection 5 years after implantation of an intraocular lens (IOL) with a blue-light filter (yellow tinted). Ophthalmology Department, University of São Paulo, São Paulo, Brazil. Prospective randomized clinical study. Patients with bilateral visually significant cataract randomly received an ultraviolet (UV) and blue light-filtering IOL (Acrysof Natural SN60AT) in 1 eye and an acrylic UV light-filtering only IOL (Acrysof SA60AT) in the fellow eye. The primary outcome measures were contrast sensitivity, color vision, and macular findings 5 years after surgery. The study enrolled 60 eyes of 30 patients. There were no significant clinical or optical coherence tomography findings in terms of age-related macular degeneration in any eye. There were no statistically significant differences in central macular thickness between the 2 IOL groups (P=.712). There were also no significant between-group differences under photopic or scotopic conditions at any spatial frequency studied. No statistically significant differences in the color discrimination test were found between the 2 IOL groups (P=.674). After 5 years, there were no significant differences in color perception, scotopic contrast sensitivity, or photopic contrast sensitivity between the blue light-filtering (yellow-tinted) IOL and the IOL with a UV-light filter only (untinted). The potential advantage of the tinted IOL in providing protection to macular cells remains unclear.

Synthesis of Plasmonic Nanocomposites for Diverse Applications

We report the synthesis of gold and silver nanostructures embedded in different dielectric matrices by atom beam co-sputtering, a novel technique. We have synthesized gold-silicon core shell nanostructures and Au-ZnO nanocomposite with tunable surface plasmon resonance (SPR) by atom beam co-sputtering and subsequent annealing. The Au-ZnO nanocomposite shows significant enhancement in intensity of Raman modes of fullerene molecules and therefore can help in surface enhanced Raman spectroscopy investigation of organic molecules. The synthesized Ag-polymer nanocomposite thin films show excellent features of broad SPR absorption extending upto IR region and a narrow transmission of light in UV region approximately 320 nm which could be of technological interest in solar absorbers and UV light filters respectively. The Ag-silica nanocomposite thin films show their utility in glucose sensing. The gold-silica nanocomposite thin films exhibit their possible use in detection of human ovarian cancer cells in a preliminary study. The shift in SPR peak of Au nanoparticles (NPs) present at the surface of silica synthesized by thermal evaporation and annealing, after attachment of biological molecules like proteins has been studied.

Moisture-resistant protective films for UV-light filter based on diisocyanate-bridged polysilsesquioxanes

Three bridged silsesquioxanes were synthesized via the reactions between 3-aminopropyltriethoxysilane and three different diisocyanates, i.e., m-xylylene diisocyanate, 1, 6-diisocyanatohexane, and isophorone diiocyanate. The subsequent bridged polysilsesquioxane sols were prepared by the room-temperatured polycondensation of these bridged silsesquioxane using basic catalysis. Transparent films with a thickness of around 330 nm were obtained by dip-coating the bridged polysilsesquioxane sols on the nickel sulfate hexahydrate (NiSO 4·6H 2O, NSH) crystal wafers that are commercially used as ultraviolet light filter working at a wavelength of 300 nm. The N 2 adsorption/desorption experimental results showed that the films were all nonporous with pore volume less than 2 × 10 − 3 cm 3 g − 1 . The obtained three polysilsesquioxanes all exhibited very high condensation degree of siloxane (above 99%). These films showed high optical transmittance at desired wavelengths (280–320 nm) and excellent moisture-resistant protection to the NSH filters.

A novel moisture-resistant film for NiSO 4·6H 2O filter based on isophorone diisocyanate-bridged polysilsesquioxane

A new bridged silsesquioxane (BSQ) was synthesized with isophorone diisocyanate (IPDI) and 3-aminopropyltriethoxysilane (APTES). Highly cross-linked bridged polysilsesquioxane (BPSQ) sol was prepared by the sol–gel polycondensation of the as-synthesized BSQ under basic catalysis. Transparent film was obtained by dip-coating the BPSQ sol on the nickel sulfate hexhydrate (NSH, NiSO 4·6H 2O) crystal wafer, an important kind of UV light filter used at wavelength 300 nm. The obtained BPSQ film was nonporous (pore volume is 2 × 10 −3 cm 3 g −1) and exhibited very high condensation degree of siloxane (99.0%). This film showed high optical transmittance and excellent moisture-resistant protection to the NSH filter. Moreover, the thermal stability of the NSH filter was also greatly improved by the as-prepared BPSQ film.

Growth and Characterization of Potassium Cobalt Nickel Sulfate Hexahydrate for UV Light Filters.

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Growth and characterisation of potassium cobalt nickel sulfate hexahydrate for UV light filters

AbstractA new single crystal for ultraviolet light filter, KCNSH (Potassium Cobalt Nickel Sulfate Hexahydrate) was designed and its crystal structure was studied using X‐ray diffraction in this paper. The empirical of the title compound is K2Co0.1Ni0.9(SO4)2.6H2O with formula weight 437.15. KCNSH crystal belongs to the monoclinic space group P2(1)/c, a=6.1390(3)Å, b=12.1839(6)Å, c=9.0095(4)Å, α=γ=90°, β=105.060(2)°, V=650.74(5)Å3, Z=2, Dc=2.231g/cm3. Using the cooling solution method, we have grown a deep green KCNSH crystal with dimension of 12×12×40mm3. The transmission spectrum of KCNSH in the range from UV to near IR wavelengths, its thermal properties, and the relationship between the structure and optical transmission properties are also studied and further discussed in this paper. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Protection against UVB irradiation by natural filters extracted from lichens

Natural substances extracted from lichens and boldo tree were tested in vivo and in vitro as possible UV-light filters. The protection factors were compared with that found for the references: Nivea sun Spray LSF 5, octylmethoxycinnamate (OMC) and 4- tert.-butyl-4′-methoxy dibenzoylmethane (BM-DBM). The stability of the single compounds was studied through UV–Vis spectroscopy. Usnic acid resulted to be the best UVB filter, with an in vivo protection factor similar to Nivea sun Spray LSF 5. Most of the single compounds studied in vitro resulted to have higher or similar filtering power than octylmethoxycinnamate. The protection factors as well as the good UV-light absorption of their photo-products suggest that these natural substances may be useful as new filters in sun-screen preparations.

UV-Assisted Graft Polymerization of N-Vinyl-2-pyrrolidinone onto Poly(ether sulfone) Ultrafiltration Membranes Using Selective UV Wavelengths

Low protein fouling 50 kDa poly(ether sulfone) ultrafiltration membranes were produced by UV-assisted graft polymerization of the monomer 1-vinyl-2-pyrrolidinone by using a dip modification technique without loss of protein rejection. UV lamps with an emission wavelength maximum of 300 nm and two specially selected UV light filters, benzene and an aromatic polyester film, were used to filter out 254 nm wavelength light which was found to be responsible for severe loss of protein rejection. The modified membranes that performed the best were prepared by using 300 nm lamps and the benzene filter. With increasing degree of grafting, these membranes exhibited up to 20% higher surface wettability (cos ϑ = 0.83−0.89) than the base membrane (cos ϑ = 0.74), which translated into lower irreversible flux loss (−0.05 to 0.03 compared with 0.42). While the protein rejection remained unchanged after modification, the permeability of the membranes decreased from 6.5 to 0.3 l m-2 h-1 (kPa)-1 with increasing degree of gr...

In situ fluorescence measurements-clarifying or blurring the picture?

Abstract