Green Light Research Articles

Complementing photothermal to photochemical actuation of assembled liquid crystal networks for wavelength-selective multimodal locomotion

The incorporation of molecular photoswitches into liquid crystal networks (LCNs) endows spatiotemporal control of their macroscale deformation and mechanical actuation in a noninvasive manner using light. Extending the photoactuation modes of LCNs to a higher level of life-like complexity and intelligence relies significantly on the rational collective utilization of multiple photoswitchable compounds. Here, we report the development of heterogeneously assembled LCN photoactuators that display well-defined stepwise actuation by assembly of new arylazopyrazole (azp)-based and conventional azobenzene (azb)-based LCN segments. Due to their activation wavelength selectivity, where azp is photochemically driven by UV light while azb is photothermally driven by green light, the assembled actuators show a high degree of photocontrollability of the overall actuation behaviors. A series of assembled actuators composed of azp and azb segments ranging from linear to branched structures are constructed to perform programmable wavelength-selective shape transformation. Bioinspired multimodal locomotion including rotating, crawling and rolling as well as optical switching between motion modes, is developed through selective irradiation to generate the robotic function for cargo transportation and release. Our work provides a useful molecular design strategy for the construction of light-driven actuators with precise photocontrollability and expanded actuation modes to better mimic the intelligent behaviors observed in nature.

Manganese doping in zinc based hybrid metal halides to realize highly stable efficient green emission and flexible radiation detection

Extensive studies have been conducted on hybrid metal halides due to their application in radiation detection, solid-state lighting, and solar cells. Here, we present an environmentally friendly zero-dimensional halide, (C9H15N3)ZnBr4, which crystallizes in the P21/c space group. This compound is highly thermally stable, and doping Mn2+ results in a bright green light emission, with an impressive internal quantum efficiency of 52.9 % and an external quantum efficiency of 45.9 % for (C9H15N3)Mn0.3Zn0.7Br4. Combining spectroscopic analysis with first-principles density functional theory (DFT), it is concluded that the high external quantum efficiency arises from efficient energy transfer from the organic component to the [MnBr4]2-. Notably, the (C9H15N3)Mn0.3Zn0.7Br4 luminescence intensity maintains 50 % of its room temperature level even at 400 K. Moreover, these doped powders display exceptional scintillation performance, higher than Bi4Ge3O12. Finally, the radioluminescence intensity of (C9H15N3)Mn0.3Zn0.7Br4@polydimethylsiloxane flexible films is about three times that of Bi4Ge3O12. These features position Mn:(C9H15N3)ZnBr4 as an ideal material for X-ray detection and an efficient green photoluminescent material.

A double-masked, sham-controlled trial of rose bengal photodynamic therapy for the treatment of fungal and acanthamoeba keratitis: Rose Bengal Electromagnetic Activation with Green Light for Infection Reduction (REAGIR) study

BackgroundInfectious keratitis secondary to fungus or acanthamoeba often has a poor outcome despite receiving the best available medical therapy. In vitro rose bengal photodynamic therapy (RB-PDT) appears to be effective against fungal and acanthamoeba isolates (Atalay HT et al., Curr Eye Res 43:1322–5, 2018, Arboleda A et al. Am J Ophthalmol 158:64-70, 2014). In one published series, RB-PDT reduced the need for therapeutic penetrating keratoplasty in severe bacterial, fungal, and acanthamoeba keratitis not responsive to medical therapy.MethodsThis international, randomized, sham and placebo controlled 2-arm clinical trial randomizes patients with smear positive fungal and acanthamoeba and smear negative corneal ulcers in a 1:1 fashion to one of two treatment arms: 1) topical antimicrobial plus sham RB-PDT or 2) topical antimicrobial plus RB-PDT.DiscussionWe anticipate that RB-PDT will improve best spectacle-corrected visual acuity and also reduce complications such as corneal perforation and the need for therapeutic penetrating keratoplasty. This study will comply with the NIH Data Sharing Policy and Policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule. Our results will be disseminated via ClinicalTrials.gov website, meetings, and journal publications. Our data will also be available upon reasonable request.Trial registrationNCT, NCT05110001, Registered on November 5, 2021.

Solid-state reaction synthesis of LuPO4:Yb3+, Tb3+ phosphors and the ultraviolet/near-infrared responsive spectra performances

Yb3+/Tb3+ co-doped LuPO4 phosphors were prepared by solid-state reaction method. The effects of Yb3+/Tb3+ doping concentrations on the downshifting and upconversion spectral performances of the synthesized phosphors were investigated. Upon the ultraviolet light excitation, the phosphors show obvious visible light emission, which can be assigned to the 5D4→7FJ (J=6, 5, 4, and 3) transitions of Tb3+ ions respectively, the green light emission at 543 nm is dominant. Upon 980 nm excitation, the phosphors display intense green and blue light emission, and weak yellow and red light emission, which originates from the cooperative energy transfer process between Yb3+ and Tb3+ ions. The synthesized LuPO4:Yb3+, Tb3+ phosphors show good ultraviolet/near-infrared responsive spectra, color-tunable and thermal-stability performances and may have potential applications in the related fields.

Evaluation of growth and nutritional profile of microgreens of different crops under various LEDs light spectrums.

Carefully selecting the appropriate lighting is vital for indoor farming systems to ensure sustainable agriculture and the production of microgreens rich in health-beneficial phytochemicals. This study aimed to investigate the impact of various light spectrums on the growth and nutritional composition of microgreens. The experiment focused on a single factor: five different concentrations of LED lights, specifically White light (L1) at 100%, Red light (L2) at 100%, Blue light (L3) at 100%, Red and Blue light (L4) at a 70:30 ratio, and Red, Green, and Blue light (L5) at a 70:10:20 ratio. Four microgreen crops were used: Mustard (C1), Lettuce (C2), Radish (C3), and Broccoli (C4). The results showed that the hypocotyl lengths of C1, C2, C3, and C4 were higher under the L4 light treatment (70:30 Red and Blue), measuring 10.53 cm, 8.47 cm, 15.23 cm, and 11.43 cm, respectively. The shorter hypocotyl lengths of 7.67, 5.53, 11.2 and 7.73 cm were observed under the L1 (White light) condition. The greater fresh weights for C1, C2, C3, and C4 (0.1 kg each) and yields (0.115 kg, 0.110 kg, 0.135 kg, and 0.125 kg, respectively) were also obtained under the L4 light condition. The higher SPAD values for C1 (38.2 nm), C2 (16.9 nm), C3 (55.3 nm), and C4 (49.9 nm) were recorded with the L4 light treatment. Additional findings included potassium content for C1 (0.19%), C2 (0.19%), C3 (0.22%), and C4 (0.16%), and antioxidant capacity for C1 (0.22%), C2 (0.23%), C3 (0.19%), and C4 (0.18%). The higher gross income was achieved with the L4C1, L4C2, L4C3, and L4C4 treatments, while the lower was with the L1C1, L1C2, L1C3, and L1C4 treatments. The benefit-cost ratios were higher (4.1, 3.9, 4.9, and 4.5) for the L4C1, L4C2, L4C3, and L4C4 treatments, respectively. Therefore, a 70:30 Red and Blue light combination (L4) can be used profitably in indoor farming to maximize growth, yield, and nutritional content of microgreens.

A novel Na2Ca2Si3O9: Tb3+ glass ceramic with high luminescence efficiency and robust thermal stability for white LED lighting application

Given the increasing demand for white light emitting diode (WLED) lighting devices marked by high color rendering indices (CRI) and exceptional thermal stability, there is a burgeoning interest in developing emitters with enhanced performance. Rare earth (RE) ion-activated glass ceramics (GCs) have garnered significant attention due to their outstanding physicochemical and thermal stability, alongside their high luminescence efficiency. In this study, the GCs doped with Tb3+ ions in the Na2O-CaO-SiO2 system matrix were synthesized, incorporating Na2Ca2Si3O9 nanocrystals averaging less than 100 nm in size. Notably, these GC materials demonstrated superior luminescence efficiency in the green light emission under the irradiation of 376 nm light compared to the parent glass. A comprehensive analysis of fluorescence spectra revealed an impressive internal quantum efficiency of 87.34 % for this Tb3+-doped GC. Furthermore, the GC retained 90 % and 84 % of the initial luminescence intensity at 150 °C and 200 °C in comparison to the luminescence level at room temperature, showcasing exceptional resistance to fluorescence thermal quenching. Verification experiments utilized UV LED chip, (Sr, Ca)AlSiN3: Eu2+ red phosphor, BaMgAl10O17: Eu2+ blue phosphor, and Tb3+-doped GC to encapsulate the WLED device, achieving a remarkable CRI of 92, CIE chromaticity coordinates (0.3547, 0.3361), and a correlated color temperature (CCT) of 4550K. In conclusion, the experimental outcomes unequivocally underscore the significant application potential of these Tb3+-doped GCs in the territory of warm WLED lighting.

Strategy to optimize the broadband near-infrared emission based on Eu2+-doped sulfureted garnet phosphors toward emerging spectroscopy applications

Eu2+-doped near-infrared (NIR) emitting phosphors, known for their high efficiency, broadband emission and spectral tunability, have gained much attention. However, achieving efficient NIR emission based on Eu2+ remains a challenge due to the co-existence of Eu3+, especially in materials (i.e. garnets and apatites) containing trivalent lanthanide cations. In this study, a Eu2+ doped sulfureted NIR-emitting garnet phosphor Ca3(Sc, Eu)2Si3(O, S)12: Eu2+ is successfully designed and synthesized. Notably, a strategy for regulating the initial valence state of dopants is proposed by using prepared EuS instead of the conventional Eu2O3 as raw material, enhancing the NIR emission by 135 %. Moreover, a sulfuration strategy is further introduced to enhance the NIR-emitting intensity and internal quantum efficiency by 192 % and 167.8 %, and to improve thermal stability by 154 % at 120 °C. The luminescence origin of the unusual broadband NIR emission is re-examined through chemical unit co-substitution strategy by introducing [Al3+Hf4+] to replace [Sc3+Si4+] ion pairs. Meanwhile, the spectral regulation and the performance optimization mechanism are systematically discussed. Finally, a green light pumped NIR LED device with a photoelectric efficiency of 9.43 %@100 mA and output power of 22.74 mW@100 mA is fabricated, showing remarkable potential in nondestructive testing and biomedical imaging applications.

Effects of intermittent lighting program and light colour on ocular health variables as welfare indicators in broiler chickens

ABSTRACT 1. The objective of the present study was to examine the effect of lighting programs and light colour on ocular health variables as welfare indicators in Ross 308 broilers. 2. A total of 384, male, one-d-old broiler chickens (Ross 308) were placed in a completely randomised design with a 2 × 2 factorial arrangement of lighting program (continuous or intermittent) and light colour (white and green LED light). Ross 308 broilers under restricted lighting had 18 h of light (18 L:6D), while those under intermittent lighting had cycles of 17 L:3D:1 L:3D throughout the experimental period, which lasted 42 d. 3. At the end of the experiment, all eyes of birds (n = 96 birds) underwent a complete ophthalmic examination, which included the Schirmer tear test I, intraocular pressure and eye dimensions. In addition, 32 broilers (eight birds per trial groups) aged 42 d underwent ophthalmic examination to include assessment of ocular ultrasound biometry. 4. Light colour had a significant influence on the mean intraocular pressure (p < 0.001). The Ross 308 broilers kept with intermittent lighting had lower eye weights (2.29 g; p < 0.05), palpebral fissure length (14.39 mm; p < 0.01), eye dorsoventral diameter (17.46 mm; p < 0.05), anteroposterior size (13.70 mm; p < 0.01) and corneal dorsoventral diameter (7.81 mm; p < 0.05) compared to those reared under restricted lighting. 5. In conclusion, these values for Ross 308 broilers may be applied in poultry ophthalmology to detect early eye disease symptoms and to help the diagnosis of tear disorders that could cause economic losses and welfare issues. Intermittent lighting and green LED light may help reduce eye health problems thus contributing to improved welfare in broilers.

Chip-scale optical phased array for broadband two-dimensional beam steering at visible wavelengths

An optical phased array (OPA) on a chip, as a novel non-mechanical beam steering technique, has attracted much attention in various applications. However, due to the challenges in fabrication and the limited transparency window of the material for visible wavelengths, current OPAs are mainly focuses on the infrared wavelengths. Despite the progress, the visible light OPAs remain the challenges to not only simultaneously work in blue, green and red light, but also implement beam steering in two dimensions for the single-wavelength. In this paper, an 8-channel broadband OPA is demonstrated, which enables two-dimensional beam steering in visible light. Along the longitudinal direction, the beam steering angle of 0.7° at 585 nm is achieved by tuning phase shifts. Along the transverse direction, the demonstrated OPA implements beam steering angle of 4.49° at 585 nm by tuning polarization degrees and 25.97° at 488–610 nm by tuning wavelengths. Therefore, the demonstrated OPA holds significant promise for commercial applications such as visual projection and free-space optical communications.

Photobiomodulation Dose-Response on Adipose-Derived Stem Cell Osteogenesis in 3D Cultures.

Osteoporosis and other degenerative bone diseases pose significant challenges to global healthcare systems due to their prevalence and impact on quality of life. Current treatments often alleviate symptoms without fully restoring damaged bone tissue, highlighting the need for innovative approaches like stem cell therapy. Adipose-derived mesenchymal stem cells (ADMSCs) are particularly promising due to their accessibility, abundant supply, and strong differentiation potential. However, ADMSCs tend to favor adipogenic pathways, necessitating the use of differentiation inducers (DIs), three-dimensional (3D) hydrogel environments, and photobiomodulation (PBM) to achieve targeted osteogenic differentiation. This study investigated the combined effects of osteogenic DIs, a fast-dextran hydrogel matrix, and PBM at specific wavelengths and fluences on the proliferation and differentiation of immortalized ADMSCs into osteoblasts. Near-infrared (NIR) and green (G) light, as well as their combination, were used with fluences of 3 J/cm2, 5 J/cm2, and 7 J/cm2. The results showed statistically significant increases in alkaline phosphatase levels, a marker of osteogenic differentiation, with G light at 7 J/cm2 demonstrating the most substantial impact on ADMSC differentiation. Calcium deposits, visualized by Alizarin red S staining, appeared as early as 24 h post-treatment in PBM groups, suggesting accelerated osteogenic differentiation. ATP luminescence assays indicated increased proliferation in all experimental groups, particularly with NIR and NIR-G light at 3 J/cm2 and 5 J/cm2. MTT viability and LDH membrane permeability assays confirmed enhanced cell viability and stable cell health, respectively. In conclusion, PBM significantly influences the differentiation and proliferation of hydrogel-embedded immortalized ADMSCs into osteoblast-like cells, with G light at 7 J/cm2 being particularly effective. These findings support the combined use of 3D hydrogel matrices and PBM as a promising approach in regenerative medicine, potentially leading to innovative treatments for degenerative bone diseases.

The impact of early-life conditions on visual discrimination abilities in free-ranging laying hens

Conditions during incubation and rearing can greatly affect the developmental trajectory of chickens, in a positive and negative way. In this study, the effect of early-life conditions on the visual discrimination abilities of adult, free-ranging laying hens was examined. These early-life treatments entailed incubation in a 12/12h green light/dark cycle and rearing with Black soldier fly larvae (BSFL) as foraging enrichment. Through a modified pebble-floor test, 171 hens of 41 to 42 wk old, housed in mobile stables with outdoor access, were tested for their ability to discriminate between food and nonfood items (mealworms and decoy mealworms). Each hen was allowed 60 pecks during the trial, from which the overall success rate, as well as within-trial learning was investigated. The latter was accomplished by dividing the 60 pecks into 3 blocks of 20 pecks and comparing the success rate between these blocks. Due to another ongoing experiment on range use, roughly half the hens received range enrichment (mealworms) at the time of testing, so this was included as a covariate in the analysis. Incubation with green light did not have an effect on the visual discrimination abilities of adult laying hens. Rearing with BSFL did have a limited beneficial effect on the visual discrimination abilities, as evidenced by a higher success rate during the first block of the visual discrimination trial. These enhanced visual discrimination abilities might be useful in a more complex free-range setting, where the animals have more foraging opportunities. Hens that received range enrichment at the time of testing, also had a higher success rate during the visual discrimination test, though they had a lower degree of test completion, likely due to habituation to the mealworms as an enrichment. The positive effects of BSFL during rearing and mealworms during the laying period stress the importance of enrichment throughout the life of the hens.

Application of the IOC Relative Energy Deficiency in Sport (REDs) Clinical Assessment Tool version 2 (CAT2) across 200+ elite athletes

ObjectiveThis cross-sectional retrospective and prospective study implemented the 2023 International Olympic Committee Relative Energy Deficiency in Sport (REDs) Clinical Assessment Tool version 2 (CAT2) to determine the current severity of...

In Vivo Injection of Reversible Optically Controlled Short Interfering RNA into Japanese Medaka Embryos (Oryzias latipes) to Regulate Gene Silencing.

Photoswitchable ortho-functionalized tetrafluorinated azobenzene-modified siRNAs (F-azo-siRNAs) were synthesized using solid-phase phosphoramidite chemistry. The activity of an F-azo-siRNA targeting enhanced green fluorescence protein (eGFP) in transgenic (Tg) Japanese Medaka (Oryzias latipes) was reversibly photocontrolled with blue (470 nm) and green (530 nm) light, to activate and inactivate the siRNA, respectively. This study highlights the first reversible in vivo study with photoswitchable siRNA. Controlling siRNA function reversibly in vivo could open new opportunities for biotech research to better understand gene function and cellular mechanisms.

Light Quality Influence on Growth Performance and Physiological Activity of Coleus Cultivars

This study investigates the influence of different light qualities, including red, green, blue, purple, and white lights, on the growth, physiological activity, and ornamental characteristics of two Coleus cultivars. Emphasizing the importance of leveraging phenotypic plasticity in plants within controlled environments, using light quality is a practice prevalent in the ornamental industry. The research explores the varied responses of two Coleus cultivars to distinct light spectra. The key findings reveal the efficacy of red light in enhancing shoot and leaf parameters in C. ‘Highway Ruby’, while red and green light exhibit comparable effects on shoot width and leaf dimensions in C. ‘Wizard Jade’. White light-emitting diodes (LEDs), particularly with color temperatures of 4100 K and 6500 K, promote root length growth in the respective cultivars. Moreover, chlorophyll content and remote sensing vegetation indices, including chlorophyll content (SPAD units), the normalized difference vegetation index (NDVI), the modified chlorophyll absorption ratio index (MCARI), and the photochemical reflectance index (PRI), along with the chlorophyll fluorescence, were significantly affected by light qualities, with distinct responses observed between the cultivars. In summary, this study highlights the transformative potential of LED technology in optimizing the growth and ornamental quality of foliage plants like Coleus, setting a benchmark for light quality conditions. By leveraging LED technology, producers and nursery growers access enhanced energy efficiency and unparalleled versatility, paving the way for significant advancements in plant growth, color intensity, and two-tone variations. This presents a distinct advantage over conventional production methods, offering a more sustainable and economically viable approach for increased plant reproduction and growth development. Likewise, the specific benefits derived from this study provide invaluable insights, enabling growers to strategically develop ornamental varieties that thrive under optimized light conditions and exhibit heightened visual appeal and market desirability.

Material synthesis, crystal structure, Hirshfeld surface and physicochemical characteristics Novel Stilbazolium crystal of 4-(2-(3-ethoxy-4-hydroxy-phenyl)-vinyl)-1-methyl pyridinium iodide (MEMPI) single crystal for NLO activity

In this study, a novel cation donor group 3-ethoxy-4-hydroxy benzaldehyde has been incorporated in the Stilbazolium cation with iodide anion to generate a new NLO activity of a single crystal of 4-(2-(3-ethoxy-4-hydroxy-phenyl)-vinyl)-1-methyl pyridinium iodide (MEMPI). The MEMPI crystal was effectively formed via the solvent evaporation technique. The structure and hydrogen bond interactions found in the molecule were determined by employing single-crystal X-ray diffraction. The compound crystallizes in the space group P21/c and monoclinic crystal pattern. The crystal structures are stabilized via intramolecular, intermolecular hydrogen bond interactions, C‒H···π, cation‒π, anion‒π, π···π stacking and lone pair-π interaction. In addition, a variety of O‒H···O, O‒H···I and C‒H···O interactions are also responsible for crystal packing. The 3D Hirshfeld surface and 2D fingerprint plots were used to examine the nature of intermolecular interaction. The 2D fingerprint maps indicate that the interactions between H···H contribute to 48.9 % of the total crystal stability. The newly synthesized material was characterized by 1H NMR and 13C NMR. In addition, the vibrational study of the synthesized molecule was performed using FTIR analysis. The grown crystal in linear optical characteristics were examined via a UV–Visible-NIR study. The photoluminescence (PL) activity of a MEMPI was studied with respect to the visible area and green colour emission was observed at 536 nm. The estimated CIE coordinates on the RGB colour gamut show the MEMPI crystal's ability to emit green light. The chemical etching approach was used to analyse the etch pit density and the growth habitat of the MEMPI crystal. The closed and open aperture Z-scan tests were carried out to determine the nature of third-order NLO susceptibility of the MEMPI crystal.

The Mechanism of 540 nm Green Light in Promoting Salivary Secretion.

Background: Although low-level laser therapy (LLLT) is a widely used noninvasive treatment because of photobiomodulation effects, its application for xerostomia remained uncertain. Tight junctions (TJs), mainly composed of claudins, occludin, and ZO family members, are crucial structures that determine material transport through paracellular pathway in salivary gland epithelial cells. This work aimed to investigate whether LLLT affected salivary secretion through epithelial TJs. Methods: Transepithelial electrical resistance (TER) measurement and paracellular permeability assay were applied to evaluate paracellular permeability in submandibular gland (SMG)-C6 cells after irradiation with 540 nm green light. Immunofluorescence and western blot were used to detect the expression of TJ proteins. Quantitative phosphoproteomics were performed to explore possible intracellular signals. Results: We found that irradiation with 540 nm green light significantly decreased TER values while increased paracellular transport in SMG-C6 cells. 540 nm green light-induced redistribution of claudin-1, -3, and -4, but not occludin or ZO-1. Moreover, above phenomena were abolished by preincubation with capsazepine, an antagonist of transient receptor potential vanilloid subtype 1. Notably, irradiation with 540 nm green light on the skin covering the whole submandibular gland regions promoted salivary secretion and attenuated lymphocytic infiltration in 21-week-old non-obese diabetic mice (n = 5 per group), a xerostomia animal model for Sjögren's syndrome. Through in-depth bioinformatics analysis and expression verification, ERK1/2 and EphA2 served as potential canonical and noncanonical signals underlying 540 nm green light. Conclusions: Our findings uncovered the novel therapeutic effects of 540 nm green light on xerostomia through regulation on the expression and distribution of TJs.

Nitrogen-Doped Carbon Dots: A New Powerful Fluorescent Dye with Substantial Effect on Bacterial Cell Labeling.

Carbon dots (CDs)-minute carbon nanoparticles with remarkable luminescent properties, photostability, and low toxicity-show potential for various applications. CDs synthesized using citric acid and urea are the least toxic to biological environments. Here, we aimed to explore the effect of CDs synthesized using citric acid and urea at 50, 33, and 25% (CDs 1/1, 1/2, and 1/3, respectively) weight ratios in a microwave on bacterial cell fluorescence sensing and labeling. The nanoscale properties of CDs were investigated via transmission electron microscopy and dynamic light scattering particle size analysis. X-ray powder diffraction confirmed the graphitic structures of CDs. X-ray photoelectron spectroscopy revealed that the nitrogen content increased gradually with increasing urea ratios, indicating functional group changes. Transient photoluminescence decay periods demonstrated superior fluorescence intensity of CDs 1/3 under blue, green, and red lights. The use of CDs was notably more efficient than traditional methods in staining bacterial cells. Fluorescence microscopy of 10 g-positive and 10 g-negative bacteria revealed enhanced staining of Gram-positive strains, with CDs 1/3 presenting the best results. The CDs exhibited excellent photostability, maintaining poststaining fluorescence for 100 min, surpassing the performance of conventional dyes. CDs could serve as potential fluorescent dyes for the rapid discrimination of Gram-positive and Gram-negative bacteria.

Surface Tension Manipulation with Visible Light through Sensitized Disequilibration of Photoswitchable Amphiphiles.

Azoarene isomerization lies at the heart of numerous applications, from catalysis or energy storage to photopharmacology. While efficient switching between their E and Z isomers predominantly relies on UV light, a recent study by Klajn and co-workers introduced visible light sensitization of E azoarenes and their subsequent isomerization as a tool coined disequilibration by sensitization under confinement (DESC) to obtain high yields of the Z isomer. This host-guest approach is, however, still constrained to minimally substituted azoarenes with limited applicability in advanced molecular systems. Herein, we expand DESC for the assembly of surfactants at the air-water interface. Leveraging our expertise with photoswitchable amphiphiles, we induce substantial alterations of the water surface tension through reversible arylazopyrazole isomerization. After studying the binding of charged surfactants to the host, we find that the surface activity differences upon visible light switching for both isomers are comparable to those obtained by UV light excitation. The method is demonstrated on a large concentration range and can be activated using green or red light, depending on the sensitizer chosen. The straightforward implementation of photoswitch sensitization in a complex molecular network showcases how DESC enables the improvement of existing systems and the development of novel applications driven by visible light.

Surface Tension Manipulation with Visible Light through Sensitized Disequilibration of Photoswitchable Amphiphiles

Azoarene isomerization lies at the heart of numerous applications from catalysis or energy storage to photopharmacology. While efficient switching between their E and Z isomers predominantly relies on UV light, a recent study by Klajn and co‐workers introduced visible light sensitization of E azoarenes and subsequent isomerization as a tool coined disequilibration by sensitization under confinement (DESC) to obtain high yields of the Z isomer. This host‐guest approach is, however, still constrained to minimally substituted azoarenes with limited applicability in advanced molecular systems. Herein, we expand DESC for the assembly of surfactants at the air‐water interface. Leveraging our expertise with photoswitchable amphiphiles, we induce substantial alterations of water’s surface tension through reversible arylazopyrazole isomerization. After studying the binding of charged surfactants to the host, we find that the surface activity differences upon visible light irradiation for both isomers are comparable to those obtained by UV light excitation. The method is demonstrated on a large concentration range and can be activated using green or red light, depending on the sensitizer chosen. The straightforward implementation of photoswitch sensitization in a complex molecular network showcases how DESC enables the improvement of existing systems and the development of novel applications driven by visible light.

Substitutional effects of the anionic group systems [BO33−], [PO43− ], and [SO42−] on the down-conversion photoluminescence properties of Y2O3:Er3+ nanophosphors

A series of Y2O3, Y2O3: Er3+ (1 %) and Y2O3-AG: Er3+ (1 %) (where AG = BO33−, PO43−, and SO42−) nanophosphors were prepared via a chemical combustion technique. The primary X-ray powder diffraction results showed that the Y2O3:Er3+ phosphor materials crystallized into a cubic standard structure, while the Y2O3-AG: Er3+ phosphor materials transformed to hexagonal and tetragonal structures for the [PO43−] and [BO33−]-based phosphors, respectively. However, no changes were observed for the [SO42−]-based phosphor materials. The scanning electron microscope micrographs revealed that the particles were formed in the nanometre range with different sizes and shapes. The fourier-transformed infrared spectra showed the presence of various structural groups in the pure Y2O3 and Y2O3-AG: Er3+ phosphors. In addition to that, the optical bandgap energy values were obtained using the diffuse reflection spectra (DRS) spectra and Kubelka-Munk function theory. Under UV-379 nm excitation for the Y2O3-AG: Er3+ phosphors, the Y2O3–SO4: Er3+ emitted the most intense green light at 563 nm wavelength. The Commission Internationale de l'Elcairage colour coordinates and correlated color temperature values indicated that the Y2O3:Er3+, Y2O3-PO4:Er3+, and Y2O3–SO4:Er3+ phosphor materials are potential candidates for producing enhanced green color components in white light-emitting diode (w-LED) applications.