White Lamps Research Articles

Effects of different artificial photosynthetically active radiation (PAR) sources and intensity on the growth and nutrient uptake in Ulva prolifera and Neopyropia yezoensis

Fluorescent lamps and semiconductor light-emitting diodes (LEDs) lamps are commonly used as artificial light sources in the indoor algae cultivation system. In this study, we tested the effect of two types of fluorescent lamps (T8 and T5) and white LED lamp on the growth, photosynthesis, and nutrient uptake rates of Neopyropia yezoensis and Ulva prolifera under three photosynthetically active radiation (PAR) conditions (80, 150 and 300 μmol photon m2 s−1). White LED and T8 fluorescent light induced the highest and the lowest growth rates, respectively, in both species under each PAR. The effect of T5 fluorescent light on growth rate depends on the species and PAR. Interestingly, the T8 fluorescent light significantly increased the uptake rate of phosphorus under all PARs and nitrogen uptake rate was enhanced under 150 μmol photon m2 s−1 in U. prolifera, which was not observed in N. yezoensis. Our results suggest that white LED lamp is a more economical and efficient artificial light source than fluorescent lamps because of their highest enhancement of growth. The optimal PAR of T5 fluorescent light for growth is lower than T8 fluorescent light in the cultivation of U. prolifera. T8 fluorescent increases phosphorous uptake rate in U. prolifera.

Investigating the response of green and red spinach microgreen yield and chlorophyll content in varied light-emitting diode and plant nutrient

Light-Emitting Diode (LED) improves photosynthesis, vegetative development, seed germination, and chlorophyll content in a controlled-environment plant cultivation system. This study used LEDs as artificial grow illumination with 4 four distinct ratios, 100% blue, 100% red, 100% white, 67%:20%:13% red:blue:white, for 12 hours. Microgreens were watered twice daily with 250 ppm of plant nutrients, using a commercial AB mix and liquid organic fertilizer. Different LED ratios have varied lux and Photosynthetic Photon Flux Density (PPFD), i.e. 100 lux and 44.26 mol·m−2·s−1 PPFD for 100% blue; 600 lux and 20.32 mol·m−2·s−1 PPFD for 100% red; 1000 lux and 95.92 mol·m−2·s−1 PPFD for 100% white; 350 lux, and 37.33 mol·m−2·s−1 for 67%:20%:13% red:blue:white; with maintained 25-27°C of temperature and 70-80% of relative humidity. The 100% white LED lamp with AB Mix as plant nutrient resulted in the best growth of red and green spinach microgreens, with height, leaf area, fresh weight, chlorophyll a, chlorophyll b, and total chlorophyll content of 2.98 cm, 1.32 cm2, 0.14 gr, 19.05 mg/ L, 11.38 mg/L, 19.76 mg/L for green spinach and 3.01 cm, 0.91 cm2, 0.08 g, 19.12 mg/L, 9.93 mg/L, 18.50 mg/L for red spinach.

Ultra-small Stokes shift induced thermal robust efficient blue-emitting alkaline phosphate phosphors for LWUV WLEDs

High power phosphor converted light emitting diodes (pc-LED) are thought to be the next generation technology for lighting and high-tech electronics applications. To achieve optimal luminous efficiency, maximal color gamut and stable color reproducibility, the discovery of high efficient phosphor materials with suitable excitation matching, narrow band emission and robust thermal stability is essential. Herein, we design and construct a new family of alkaline phosphate phosphors ANa3Mg7(PO4)6:Eu2+ (ANMP:Eu2+, A = K, Rb and Cs) with rigid diamond-like chain structure. The results indicates that ANMP:Eu2+(A = K, Rb and Cs) phosphors exhibit ultra-small Stokes shift and efficient blue emission (λmax = 444–465 nm) with high internal quantum efficiency (IQE = 83.2%, 90.6% and 93.4% for A = K, Rb and Cs), narrow full width at half maximum (FWHM∼50 nm) and low thermal quenching (87.5%, 96.5% and 84.2%@140 °C for A = K, Rb and Cs), which demonstrate to have higher colorful purity, wider color gamut and better wavelength applicability for using in long-wavelength near ultraviolet (LWUV) LEDs, compared with the traditional commercially available blue phosphor BaMgAl10O17:Eu2+ (BAM:Eu2+). The Eu2+ site preferences and thermal quenching mechanism are studied in detail. Moreover, the in situ temperature dependent Raman spectra and density function theory (DFT) are employed to get better comprehensions of the relationship between crystal-electronic structures and luminescent properties from experiment and calculation, which will provide a good guidance for develop new phosphors with high QE and excellent thermal stability. Finally, utilizing the title phosphors, white LED lamps are fabricated with high color rendering index and an appropriate correlated color temperature. Therefore, all the results demonstrate that the blue-emitting phosphor ANMP:Eu2+ (A = Cs, K, Rb) has great potential for applications in high power LWUV pumped pc-LEDs.

Batch and Continuous Flow Treatment Studies of Trichloroethylene Contaminated in Water by Silver and Cerium Doped Zinc Oxide Adsorption and Photocatalysis

The development of photocatalytic treatment in continuous flow systems to be more practical is challenging. This research aimed to study batch and continuous flow treatment of trichloroethylene (TCE) contaminated in water by silver and cerium doped zinc oxide (0.005Ag-0.005Ce-ZnO) visible light driven photocatalyst. This catalyst was selected to represent the green route synthesis with simplicity and ease of upscaling. The 0.005Ag-0.005Ce-ZnO powder was synthesized using sticky rice flour as a template. Mechanical coating of the 0.005Ag-0.005Ce-ZnO powder on activated alumina (Al2O3) beads was done to improve the appropriate packing in the fixed bed columns. Characterization of 0.005Ag-0.005Ce-ZnO showed a higher response to visible light and smaller crystallite size compared to zinc oxide synthesized with the same method. Using sticky rice starch as a template increased the uniform distribution of the elements. The photocatalytic batch test over 0.005Ag-0.005Ce-ZnO powder, 0.30 g/100 mL, could remove TCE up to 80% in 180 min. The decrease of TCE via photocatalysis compared to volatilization, adsorption, and photolysis presented the predominance of photocatalysis. Langmuir-Hinshelwood kinetics described that the decrease of TCE more depended on the reaction than adsorption. In addition, the TCE degradation steadily remained at 80-90% along the run of 0.005Ag-0.005Ce-ZnO@Al2O3 photocatalysis under visible light from both warm white lamps and sunlight in the continuous flow system. Besides photocatalysis, TCE adsorption on 0.005Ag-0.005Ce-ZnO@Al2O3 packed in the columns showed significant results. Our findings presented the possibility of applying the photocatalytic continuous flow system to remove TCE in industrial wastewater.

Green and free hazardous substances of neem oil lotion in promising market sustainability

The demand for cosmetics has risen in recent years, resulting in mass production that does not adhere to any acceptable standards. Many of them contain potentially harmful substances, including hydroquinone, talcum, parabens, steroids, phthalates, fragrances, and heavy metals like lead and arsenic. The current study focused on producing neem oil lotion with free steroids, hydroquinone, and parabens. Prior to the testing, neem oil lotion was prepared by adding diluted neem oil, aloe vera and Vitamin E to the basic cream lotion. Thin Layer Chromatography (TLC) was used to analyze the steroid content. The spots that appeared were observed at different wavelengths; White Lamp (T-White), UV-254 nm, and UV-366 nm. The hydroquinone was run by High-Performance Liquid Chromatography (HPLC) and was observed under UV light at 254 nm. The parabens test was also done by HPLC under UV light at 280 nm. The analysis showed that the four types of steroids; dexamethasone, bethamethasone, triamcinolone acetonide, and hydrocortisone acetate, were not detected. Furthermore, no hydroquinone was observed, as proved by the HPLC chromatogram peak. In the parabens analysis, only methylparaben was detected in the sample with a concentration of 0.011 mg/mL, below the detection limit. The other three types of parabens; ethylparaben, propylparaben, and butylparaben, were not detected in the neem oil lotion formulation. The result showed that the prepared neem oil lotion was free from these hazardous substances; steroids, hydroquinone and parabens. It confirmed that the green source of neem leaf extract lotion had no hazardous substance and was safe to use.

The influence of LED lighting on the development of Monarda L. in the conditions of hydroponics

The article presents the results of a study of the significance of the influence of the white and combined (red-blue-white) light spectrum on the growth and productivity of plants of the genus Monarda L. in the conditions of hydroponics. The optimal lighting mode has been found for the highest productivity of the monarda. A quantitative analysis of the content of photosynthetic pigments was carried out. The yield, leaf size and content of photosynthetic pigments in monarda leaves when grown under white LED lamps turned out to be higher than under colored ones.

White light thermoplasmonic activated gold nanorod arrays enable the photo-thermal disinfection of medical tools from bacterial contamination.

The outspread of bacterial pathogens causing severe infections and spreading rapidly, especially among hospitalized patients, is worrying and represents a global public health issue. Current disinfection techniques are becoming insufficient to counteract the spread of these pathogens because they carry multiple antibiotic-resistance genes. For this reason, a constant need exists for new technological solutions that rely on physical methods rather than chemicals. Nanotechnology support provides novel and unexplored opportunities to boost groundbreaking, next-gen solutions. With the help of plasmonic-assisted nanomaterials, we present and discuss our findings in innovative bacterial disinfection techniques. Gold nanorods (AuNRs) immobilized on rigid substrates are utilized as efficient white light-to-heat transducers (thermoplasmonic effect) for photo-thermal (PT) disinfection. The resulting AuNRs array shows a high sensitivity change in refractive index and an extraordinary capability in converting white light to heat, producing a temperature change greater than 50 °C in a few minute interval illumination time. Results were validated using a theoretical approach based on a diffusive heat transfer model. Experiments performed with a strain of Escherichia coli as a model microorganism confirm the excellent capability of the AuNRs array to reduce the bacteria viability upon white light illumination. Conversely, the E. coli cells remain viable without white light illumination, which also confirms the lack of intrinsic toxicity of the AuNRs array. The PT transduction capability of the AuNRs array is utilized to produce white light heating of medical tools used during surgical treatments, generating a temperature increase that can be controlled and is suitable for disinfection. Our findings are pioneering a new opportunity for healthcare facilities since the reported methodology allows non-hazardous disinfection of medical devices by simply employing a conventional white light lamp.

UV-excited single-component white phosphor of Lu2WO6 with broad-band emission for pc-WLED.

Obtaining white light from a single-component phosphor is still a significant challenge due to the complex energy transfer between multiple luminescent centers. Herein, white light emission is obtained in a single-component lutetium tungstate without any doping elements. By tuning the pH values during the hydrothermal synthesis, the orthorhombic Lu2W3O12 transformed into monocline Lu6WO12 and rhombohedra Lu6WO12. Only the monoclinic Lu2WO6 phase emitted light, whereas the other two phases did not. The main reason was that the exciton binding energy of Lu2WO6 was larger than that of Lu2W3O12 and Lu6WO12. Except for the 480 nm intrinsic emission of Lu2WO6, new long-wavelength excitation and emission bands were observed with the center at 340 nm and 520 nm. Based on the first-principle calculation, this new photoluminescence band comes from the electron transition between the local states of oxygen vacancies and valence band. Owing to this new broad-band emission, the white light LED lamp is fabricated by combining Lu2WO6 phosphor synthesized at pH values of 4.5 and 6 and 365 nm LED chips. The CIE coordinates of the pc-WLEDs are (0.346, 0.359) and (0.380, 0.380), respectively, and both are located in the white light region. Our research demonstrated a facile way to obtain a single-component white light emission phosphor without any doping components for pc-WLED applications.

Powder synthesis and luminescence of a novel yellow-emitting Ba5Si11Al7N25: Eu2+ phosphor discovered by a single-particle-diagnosis approach for warm w-LEDs

White LEDs combined by blue LED chip and yellow YAG: Ce phosphor are the mainstream of the lighting industry. However, due to the lack of red light component, it is difficult to meet the requirements of warm white lighting. The novel needle-like Ba5Si11Al7N25:Eu2+ particle discovered by the single-particle-diagnosis method shows a broad yellow emission band centered at ∼570 nm and a FWHM of 98 nm. Compared with YAG: Ce phosphor, the novel Ba5Si11Al7N25:Eu2+ phosphor exhibits longer emission wavelength, indicating potential application in warm white LEDs. In this work, the phase-pure powder of Ba5Si11Al7N25:Eu2+ is obtained in a non-stoichiometric ratio by the double-crucible method, and it shows similar luminescent properties as the single particle. Upon excitation with violet light (400 nm), the maximum emission wavelength of the as-prepared Ba5(1-x)Si11Al7N25: 5xEu2+ phosphors shift from 558 nm to 591 nm with Eu2+ ions concentration increasing, and the full width at half-maximum (FWHM) increase from 87 nm to 100 nm. The broad emission band is attributed to three luminescent centers corresponding to three different Ba2+ ions sites Ba5Si11Al7N25:Eu2+ phosphor, which is demonstrated by time-resolved emission spectra and the decomposition of the emission spectrum at 4 K. The Ba5Si11Al7N25:Eu2+ phosphor shows a small thermal quenching with a quenching temperature as high as 700 K. The as-prepared phosphor can absorb both of UV and blue light effectively and exhibits similar quantum efficiency under the excitation of 400 nm (58.5 %) and 450 nm (54.5 %). The fabricated white LED lamp emitted a warm white light with CIE coordinates of (0.3838, 0.3252) and CCT = 3412 K, implying the potential applications in warm w-LEDs.

Применение освещения различного спектрального диапазона при клональном микроразмножении лесных ягодных растений

Creation of plantations of the most popular species of forest berry plants with high nutritional and medicinal value is advisable in connection with the reduction of such natural resources and the increased demand for berry products, as well as for the biological reclamation of depleted peat deposits. The paper shows the research results of clonal micropropagation of forest berry plants (cranberry, American cranberry, half-high blueberry, Arctic bramble, lingonberry, Kamchatka bilberry) of promising cultivars and forms using various types of lighting (white LED lamps, LED lamps with a combination of white, red and blue spectra, as well as white fluorescent lamps). Plants were cultivated using WPM and MS nutrient media with the addition of cytokinins 2-iP and 6-BAP in various concentrations. The largest number (3.3–16.9 pcs) and the maximum total length (13.8–251.1 cm) of microshoots of cranberry (Dar Kostromy cultivar, hybrid form 1-15-635), American cranberry (Ben Lear cultivar, hybrid form 1-23-3), Arctic bramble (Anna cultivar, hybrid form K-1), lingonberry (Kostromskaya rozovaya and Rubin cultivars) and Kamchatka bilberry (Sakhalinskaya and Kurilskaya forms) were observed under lighting by LED lamps with a combination of white, red and blue spectra at the “proper micropropagation” stage. The formation of the largest number (13.1 pcs) and the maximum length (98.7 cm) of microshoots of half-high blueberry (Northblue cultivar, hybrid form 23-1-11) was observed under lighting by white fluorescent lamps. There were no significant differences in biometric parameters of plants under different types of lighting depending on cultivars and forms. The use of LED lamps with a combination of white, red and blue spectra has a significant effect on the formation of microshoots of forest berry plants during clonal micropropagation. For citation: Makarov S.S., Upadyshev M.T., Kuznetsova I.B., Zaushintsena A.V., Kulikova E.I., Surina E.A. The Use of Lighting of Various Spectral Ranges for Clonal Micropropagation of Forest Berry Plants. Lesnoy Zhurnal = Russian Forestry Journal, 2022, no. 6, pp. 82–93. (In Russ.). https://doi.org/10.37482/0536-1036-2022-6-82-93

Super-multiplexing excitation spectral microscopy with multiple fluorescence bands.

Fluorescence microscopy, with high molecular specificity and selectivity, is a valuable tool for studying complex biological systems and processes. However, the ability to distinguish a large number of distinct subcellular structures in a single sample is impeded by the broad spectra of molecular fluorescence. We have recently shown that excitation spectral microscopy provides a powerful means to unmix up to six fluorophores in a single fluorescence band. Here, by working with multiple fluorescence bands, we extend this approach to the simultaneous imaging of up to ten targets, with the potential for further expansions. By covering the excitation/emission bandwidth across the full visible range, an ultra-broad 24-wavelength excitation scheme is established through frame-synchronized scanning of the excitation wavelength from a white lamp via an acousto-optic tunable filter (AOTF), so that full-frame excitation-spectral images are obtained every 24 camera frames, offering superior spectral information and multiplexing capability. With numerical simulations, we validate the concurrent imaging of 10 fluorophores spanning the visible range to achieve exceptionally low (∼0.5%) crosstalks. For cell imaging experiments, we demonstrate unambiguous identification of up to eight different intracellular structures labeled by common fluorophores of substantial spectral overlap with minimal color crosstalks. We thus showcase an easy-to-implement, cost-effective microscopy system for visualizing complex cellular components with more colors and lower crosstalks.

Fabrication of W-LEDs by Coating Tri-Color Inorganic Phosphors on UV-Diode

YAG:Ce phosphor coated on blue-chip gives many advantages, except the color rendering of the LEDs fabricated by this method is poor due to the lack of red and green colors. This problem can be sorted out by choosing different methods out of the available two different methods. For the first method, the n-UV (near-ultraviolet) LED is coated with a mixture of intense blue, green, and red phosphors to make a white light-emitting diode. Also, if the yellow color phosphor is added, lamps can give better CRI values. So many papers are reported on this type of white LED fabrication technique. In this paper, we have reported the fabrication of white LED lamps by coating three different phosphors i.e. blue, green, and red in the appropriate amount to be mixed and coated on the near UV LED chips. This approach is different from the existing reports because we are using near UV (405-407 nm LEDs) not the UV LED chips in the fabrication of white LEDs in this paper.

Enhanced biomass growth of lactobacillus acidophilus with CdS-NPs under visible light irradiation: Semi-artificial biohybrid system

The bacterial biomass growth in a semi-artificial biohybrid system composed of cadmium sulfide nanoparticles (as a light-harvesting semiconductor) and Lactobacillus acidophilus (as the non-pathogenic electron acceptor bacterium) was investigated. The photo-induced electrons generated from cadmium sulfide nanoparticles within the culture medium efficiently enhanced the biomass growth (about 1.15-fold) and indicated a significant difference (P-value = 0.003 (<0.05)) after 48 h of incubation at 37 °C under white light-emitting diode lamp (12 W) compared to the dark control (i.e. culture grown without nanoparticles and light exposure). Scanning electron microscopy indicated the well-distributed spherical nanoparticles on the smooth surface of the bacterium. Energy-dispersive X-ray spectroscopy revealed the presence of nanoparticles on the bacterium cell surface. The findings of this study revealed that integrating cadmium sulfide nanoparticles with Lactobacillus acidophilus under visible light irradiation had a positive effect on bacterium growth.

Energy-efficient production of vaccine protein against porcine edema disease from transgenic lettuce (Lactuca sativa L.)

The development of functional protein production systems using transgenic plants as hosts has been rapidly progressing in recent years. Lettuce (Lactuca sativa L.) has been studied as one such host, and it has been reported that the biomass of lettuce per area and target protein expression level can be increased by optimizing the cultivation conditions. Therefore, we investigated methods to minimize the input light energy per target protein to reduce production costs. Herein, we examined the yield of a nontoxic B subunit of Stx2e (Stx2eB) from transgenic lettuce under various cultivation conditions. Stx2eB acts as a vaccine against swine edema disease. The effects of photon flux densities (PPFDs), photoperiod, and light source on Stx2eB production were examined and the findings suggested that 400 μmol m−2 s−1, 24 h, and white LED lamps, respectively, contributed to energy-efficient Stx2eB production. In addition, Stx2eB was produced 1.4 times more efficiently per unit area time using a high plant density (228.5 plants m−2) than a common density (30.4 plants m−2). The findings of the present study can facilitate the development of energy-efficient and low-cost production processes for vaccine protein production, considering temporal and spatial perspectives.

Physicochemical properties of Li3Ba2La3(MoO4)8:Eu,Tb red-emitting phosphor for solid state white lamps

In this work, combustion synthesis was used for the first time to fabricate a phosphor material with red emission for applications in solid-state white-light lamps. We synthesized a material with emission wavelength at λem = 617 nm, excited under long UV-blue wavelength based on Eu3+, Tb3+-activated molybdates Li3Ba2(La1–x–yEuxTby)3(MoO4)8 with 0 ≤ x ≤ 1 and 0 ≤ y ≤ 1. A series of powder samples were produced by the combustion method and post-annealed at 800 °C in air. The crystalline phase formation was investigated by X-ray diffraction, which reveals the monoclinic C2/c (15) space group. It is observed that crystalline structure and morphology are preserved when the host lattice is doped with Eu3+ or Tb3+ single ions and co-doped with both ions at different doping concentrations. A detailed characterization by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) shows a similar morphology in all samples: rather large (1–7 μm) agglomerate particles with irregular shapes and surrounded by smaller nanoparticles of 50 nm in size. UV–visible absorption spectra confirm the presence of Eu3+ and Tb3+ ions. The luminescent properties of the obtained phosphors were studied in detail. Cathodoluminescence measurements indicate that the best emission intensity is for Eu3+:Tb3+ doping ratios of 80:0, 90:0 and 20:80. On the other hand, samples with 80:0, 60:40, and 20:80 doping ratios show the highest intensity in a detailed photoluminescence analysis and they exhibit the highest quantum yield values. A complete and efficient energy transfer from the sensitizer Tb3+ to the activator Eu3+ is observed in all co-doped phosphors post-annealed at 800 °C for 4 h. Thus, the Li3Ba2La3(MoO4)8:Eu3+,Tb3+ materials fabricated by combustion synthesis are excellent phosphors for being applied as red-emitting component in solid-state white-light lamps due to an improved color rendering index (CRI) that can be obtained under long UV-blue excitation wavelengths.

Flexible, disposable photocatalytic plastic films for the destruction of viruses.

A thin, 30 μm, flexible, robust low-density polyethylene, LDPE, film, loaded with 30 wt% P25 TiO2, is extruded and subsequently rendered highly active photocatalytically by exposing it to UVA (352 nm, 1.5 mW cm−2) for 144 h. The film was tested for anti-viral activity using four different viruses, namely, two strains of Influenza A Virus (IAV), WSN, and a recombinant PR8, encephalomyocarditis virus (EMCV), and SARS-CoV-2 (SARS2). The film was irradiated with either UVA radiation (352 nm, 1.5 mW cm−2; although only 0.25 mW cm−2 for SARS2) or with light from a cool white fluorescent lamp (UVA irradiance: 365 nm, 0.047 mW cm−2). In all cases the films exhibited an average virus inactivation rate of >1.5log/h. In the case of SARS2, the rates were > 2log/h, with the rate determined using a dedicated, low intensity UVA source (0.25 mW cm−2) only 1.3 x's faster than that for a cool white lamp (UVA irradiance = 0.047 mW cm−2), which suggests that SARS2 is particularly prone to photocatalytic inactivation even under low UV irradiation conditions, such as found in a room lit with just white fluorescent tubes. This is the first example of a flexible, very thin, photocatalytic plastic film, produced by a scalable process (extrusion), for virus inactivation. The potential of such a film for use as a disposable, self-sterilising thin plastic material alternative to the common, non-photocatalytic, inert equivalent used currently for curtains, aprons and table coverings in healthcare is discussed briefly.

Randomized Clinical Trial of Conventional versus Indoor Daylight Photodynamic Therapy for Treatment of Actinic Cheilitis.

IntroductionActinic cheilitis (AC) is the biologic precursor of invasive squamous cell carcinoma (SCC) of the vermilion, and different treatment options have been investigated, but their efficacy is hampered by local inflammation, pain and slow recovery. Daylight photodynamic therapy (dl-PDT) has been demonstrated to represent a valuable treatment option for AC, but its feasibility is limited by weather conditions and latitude.MethodsOur study proposed to compare the efficacy and tolerability of conventional photodynamic therapy (c-PDT) and indoor daylight photodynamic therapy (idl-PDT) with a white LED lamp for the treatment of AC. Sixteen patients were enrolled in the study: 8 (50%) treated with c-PDT and 8 (50%) treated with idl-PDT. All patients completed the study protocol.ResultsBoth idl-PDT and c-PDT were demonstrated to be highly effective in terms of reduction of the cumulative lesional area and severity of the clinical score. Neither treatment was inferior to the other. The inflammatory reaction and the pain scores were milder with idl-PDT, whereas the cosmetic outcome was not different.ConclusionThe present findings confirm that idl-PDT can represent a valid therapeutic strategy for AC patients as well, despite the procedural difficulties and the risk of poor tolerability related to the body site.

Biological/metal oxide composite transport layers cast from green solvents for boosting light harvesting response of organic photovoltaic cells indoors

Organic solar cells with biological/metal–oxide electron transport layers (ETLs), consisting of a ZnO compact layer covered by a thin DNA layer, both of which deposited with green solvents (water or water/alcohols mixtures) are presented for application under low intensity indoor lighting. Under white LED lamp (200, 400 lx), photovoltaic cells with P3HT:PC70BM polymer semiconductor blends delivered an average maximum power density (MPD) of 8.7 μW cm−2, corresponding to a power conversion efficiency, PCE, of = 8.56% (PCE of best cell was 8.74%). The ZnO/DNA bilayer boosted efficiency by 68% and 13% in relative terms compared to cells made with DNA-only and ZnO-only ETLs at 400 lx. Photovoltaic cells with ZnO/DNA composite ETLs based on PTB7:PC70BM blends, that absorb a broader range of the indoor lighting spectrum, delivered MPDs of 16.2 μW cm−2 with an estimated average PCE of 14.3% (best cell efficiency of 15.8%) at 400 lx. The best efficiencies for cells fabricated on flexible plastic substrates were 11.9% at 400 lx. This is the first report in which polymer photovoltaics incorporating biological materials have shown to increment performance at these low light levels and work very efficiently under indoor artificial light illumination. The finding can be useful for the production of more bio-compatible photovoltaics as well as bio-sensing devices based on organic semiconductors.

The crystal structures and fluorescent properties of BaLu1.95Ce0.05Al4-xGaxSiO12 (1≤x≤2.5) solid solutions

Currently, the green and cyan emitting phosphors are indispensable for white LEDs with high color rendering index. However, the phosphors which can be effectively excited by blue light and have excellent thermal stability are numbered. Here, a series of new solid solutions of BaLu1.95Ce0.05Al4-xGaxSiO12 (1 ≤ x ≤ 2.5) was successfully synthesized by the conventional solid-state reaction method. Their crystal structures and fluorescent properties are investigated systematically. BaLu1.95Ce0.05Al4-xGaxSiO12 (1 ≤ x ≤ 2.5) crystallized in the cubic system with the space group Ia3‾d. All the O resides at Wyckoff position 96h. Ba/Lu/Ce (Wyckoff position 24c) and O form a dodecahedron, Al/Ga (Wyckoff position 16a) and O make up an octahedron, Al/Ga/Si (Wyckoff position 24d) and O constitute a tetrahedron. The unit cells are composed by the dodecahedrons, octahedrons and tetrahedrons. It is found that BaLu1.95Ce0.05Al3GaSiO12 and BaLu1.95Ce0.05Al2.5Ga1.5SiO12 have extra-high quantum yield and excellent thermal stability of fluorescence. Their quantum yield excited by 448 nm blue light exceeds 97%. At 150 °C, their emission intensity can remain more than 92% of that at 25 °C. As the temperature rises from 25 to 200 °C, their emission color shifts are very small. The white LED lamp fabricated by using the BaLu1.95Ce0.05Al2.5Ga1.5SiO12 phosphor exhibits outstanding optical properties with Ra = 92.4, CRI = 90.1, CCT = 4593 K and CIE 1931 chromaticity values as (x = 0.3513, y = 0.3221). All the experimental data demonstrates that BaLu1.95Ce0.05Al3GaSiO12 and BaLu1.95Ce0.05Al2.5Ga1.5SiO12 have great application prospects in white LEDs as cyan-green phosphors.

Continuous-flow CvFAP photodecarboxylation of palmitic acid under environmentally friendly conditions

The fatty acid photodecarboxylase from Chlorella variabilis NC64A (CvFAP) promotes the elimination of CO2 from fatty acids (Cn) producing the corresponding hydrocarbon (Cn-1). Therefore, this enzyme is of great biotechnological interest since it can be used in alternative biofuel production routes matching the concept of green chemistry. However, due to its recent discovery, this reaction still requires optimizations, which was the focus of the present work together with the application of continuous flow system. The results in batch reactors showed the importance of using high power LED lamps (300 W) to reduce the reaction time for full conversion (30 min, >99%). In another approach, a continuous flow system demonstrated high potential, as it enabled full conversion with a half concentration of enzyme extract in a very short residence time of 15 min. Furthermore, the use of less expensive and sustainable light sources, not previously reported for reactions with CvFAP, were evaluated with full conversion (>99%) after 1 h for continuous flow reactions using 300 W common white LED lamp and based preliminary batch reactions investigations using direct sunlight. Thus, important advances and new perspectives for CvFAP photodecarboxylation reactions could be achieved with the present report.