Color Light-emitting Diode Research Articles

Performance of Triple-Cation Perovskite Solar Cells under Different Indoor Operating Conditions.

We systematically analyze triple-cation perovskite solar cells for indoor applications. A large number of devices with different bandgaps from 1.6 to 1.77 eV were fabricated, and their performance under 1-sun AM1.5 and indoor white light emitting diode (LED) light was compared. We find that the trends agree well with the detailed balance limit; however, the devices near the optimal bandgap (1.77 eV) perform worse due to the lower perovskite quality. Instead, we achieve the highest power conversion efficiency (PCE) of 34.0% under 870 lx with 1.67 eV and Al2O3 passivation. The perovskite with a bandgap of 1.71 eV is not far behind, with a high VOC of 1.02 V. Measurements under different white LED color temperatures confirm that the highest PCE is achieved under the warmest colors. All measurements were carried out in a dedicated indoor setup that ensures the diffuse light typical of indoor environments and allows both short- and long-term measurements. In the best case, we observe no degradation during the 33-day test under simulated office conditions with regular switching on and off of the light and a T80 of 30 days under continuous illumination. The results were obtained from multiple batches, which corroborates our findings and gives them statistical relevance.

Rapid alignment-free bacteria identification via optical scattering with LEDs and YOLOv8

Rapid and accurate bacterial identification is essential for timely treatment of infections like sepsis. While traditional methods are reliable, they lack speed, and advanced molecular techniques often suffer from cost and complexity. The bacterial detection technology based on optical scattering system offers a rapid, label-free alternative but traditionally relies on complex lasers and analysis. Our enhanced approach utilizes RGB light emitting diodes (LEDs) as the light source. Three diffraction images of bacterial colonies from different LED colors are separately captured by a USB camera and combined using an image registration algorithm to enhance image sharpness. Our approach utilizes an object detection model, i.e., YOLOv8, for analysis achieving high-accuracy differentiation between bacterial strains. We demonstrate the effectiveness of this approach, achieving an average accuracy of 97% (mAP50 of 0.97), including accurate discrimination of closely related strains and the significant pathogen Staphylococcus aureus MRSA 1320. Our enhancement offers advantages in affordability, usability, and seamless integration into existing workflows, providing an alternative for rapid bacterial identification.

Yellow light emitting Cs2Zr0.99Te0.01Cl6 with high efficiency emission via modified co-precipitation method synthesis for the light-emitting device

While lead-free perovskite has attracted widespread interest in the optical field by overcoming their toxicity and stability disadvantages compared to conventional lead-based perovskite, the low photoluminescence quantum yield (PLQY) of lead-free perovskite has greatly limited their commercialization path. In this research, a modified co-precipitation method was used to prepare Cs2ZrCl6, which was achieved by the addition of TeCl4 to shift the emission wavelength from 436 to 556 nm with bright yellow emission, the optimal PLQY of 98.2% was achieved by the addition of Te4+ in the amount of 1 % and the optimization of the reaction concentration. First-principles calculations and spectral analysis of Cs2Zr1-xTexCl6 show that the broadband yellow light emission comes from self-trapped excitons (STEs) in Cs2Zr1-xTexCl6. In addition, the luminous intensity of the prepared Cs2Zr1-xTexCl6 was 57.3, 63.3 and 90.1% of the initial intensity after exposure to air for 30 d, cyclic intermittent heating to 200°C and ultraviolet (UV) irradiation for 7 d, respectively. Finally, Cs2Zr1-xTexCl6 and Cs2ZrCl6:10% Bi were used as phosphors and encapsulated with a UV chip to make three different colors of light-emitting diodes (LED), where the white LED (WLED) had CIE coordinates of (0.3061 0.3244), color temperatures, color rendering indices as well as color tolerances of 6921 K, 84 and 6.52 respectively. This research provides a new approach to improve the performance of lead-free perovskite.

Preparation and properties of tellurite glass-based CsPb(BrCl)3@glass fluorescent film for a white light emitting diode color converter

Perovskite nanocrystal glass has the advantages of narrow-band emission, easy tuning, and stable structural, physical, and chemical properties, and can be used to mix with other colored materials for white light modulation. The current white light mode widely adopts the packaging method of blue light chip and yellow phosphor, which has the problem of a blue-yellow cavity and low light quality. In this work, the central wavelength of CsPb(BrCl)3 can be adjusted continuously ranging from 463 nm to 486 nm by adjusting the relative ratio of bromine to chlorine in nanocrystals. On the basis of the previous design of YAG:Ce phosphor-in-glass, perovskite nanocrystal glass powder as a color compensator was introduced into the tellurite glass matrix to form a doubly encapsulated system by low-temperature co-sintering. The yellow phosphor and perovskite nanocrystal glass maintain good structural integrity in the glass matrix. By combining the double-package fluorescent material with the blue chip, the continuous adjustment of chromaticity coordinates along the saddle line is realized, and the color-rendering index is also improved to 81.3.

Enhancing secret key distribution through advanced color modulation in visible light communication

Visible light communication (VLC) has emerged as a dynamic area of research poised to revolutionize high-speed wireless communication. VLC technology uses light-emitting diodes (LEDs) within existing infrastructure to emit light within the visible spectrum. VLC complements traditional radio frequency (RF) communications, addressing its inherent limitations and drawbacks. To navigate the demands of modern urban environments, VLC systems must prioritize secure data transmission, accessibility, and economic feasibility, particularly within the framework of smart cities. We introduce what is to our knowledge a novel privacy-enhanced VLC system for optical wireless communication. Leveraging color data modulation techniques and the intricacies of a hyperchaotic three-dimensional map, this innovative approach ensures robust security. By employing diverse LED colors for data transmission and exploiting the unpredictable mathematical properties of hyperchaotic maps, enhanced privacy is achieved. The performance of the proposed system was rigorously evaluated through various tests, manipulating initial control parameters of the encryption process with the hyperchaotic map, as well as adjusting message length and content. Tests were conducted over a 1 m connection distance at a symbol transmission rate of 2 baud. Remarkably, the proposed system demonstrated high accuracy in message recovery, achieving a symbol error rate (SER) of only 0.02 at an incident optical power of 22 µW. We highlight the critical importance of precise decryption parameter values in the proposed method, demonstrating the necessity for accuracy within the range of 10−15 for each decryption parameter; it underscores the indispensability of meticulous parameter calibration to ensure the correct decryption of transmitted symbols. These results pave the way for applications where absolute security is imperative, particularly in smart city environments, such as for key distribution purposes.

Preparation of BaAl2-xGaxSi2O8:Ce3+, M+ (Li, Na, K) blue-cyan phosphors based on charge compensation and cation substitution strategies and luminescence performance study

Highly efficient blue-cyan phosphors can fill the cyan gap in conventional white light-emitting diode (LED) devices to improve the spectral continuity while effectively increasing the white LED colour rendering index (Ra). In this study, Ba0·94Al2-xGaxSi2O8:0.06Ce3+, M+ (Li, Na, K, x = 0–0.8) blue-cyan phosphors with a feldspar structure were prepared by a high-temperature solid-phase method using charge compensation and cation substitution strategies. The barium (Ba) vacancy due to the charge-imbalance substitution of Ce3+ is compensated by the different charge compensators Li+, Na+, and K+. The charge compensators affect the luminescence performance of the samples, with the K+-compensated samples showing the greatest enhancement, with intensities up to 1.8 times that of the uncompensated samples. The cation substitution strategy using Ga3+ to partially replace Al3+ further improves the luminescence performance of the Ba0·94Al2Si2O8:0.06Ce3+, 0.04 K+ sample, and the excitation band is also improved. In this case, the luminescence intensity of the Ba0·94Al2Si2O8:0.06Ce3+ luminescent material is increased by a factor of 6, and a broadband blue-cyan phosphor with a full-width at half-maximum of 118 nm containing blue, cyan and green is obtained. The co-doping of charge compensators and partial cation substitution improved the luminescence performance of phosphors. The representative sample Ba0·94Al1.6Ga0.4Si2O8:0.06Ce3+, 0.04 K+ has a luminescence intensity at a temperature of 150 °C that is 83.2% of that at room temperature and good thermal stability. The combination of 365 nm near-ultraviolet (NUV) LED chips with Ba0·94Al1.6Ga0.4Si2O8:0.06Ce3+, 0.04 K+ and the commercial red powder (Ca, Sr)AlSiN3:Eu2+ yields a white LED device with an Ra of up to 93 and a correlated colour temperature (CCT) of 4825 K. These results show that the blue-cyan phosphor complements the cyan component while simplifying the manufacturing process of white LEDs.

Characterization of GaN‐Based Nanopillar Light‐Emitting Diodes on Multicrystalline Si Substrates: Insights into Emitting‐Color Distribution Characteristics

In a previous study, GaN‐based nanopillars are grown vertically on a multicrystalline Si substrate by inserting (In)GaN steering crystals. In addition, blue‐green and white light‐emitting diodes (LEDs) are prepared on this substrate for the first time using a double heterotype p–n junction. Herein, the emission‐color distribution characteristics of this type of LED are analyzed in depth, and a related luminescence principle is proposed. Each nanopillar plus an electrode is considered a nanopillar LED, and the emission color of each nanopillar LED is inferred. The indium distribution in the InGaN active region is predicted based on the luminous color and corresponding spectra. Simultaneously, the morphology of related materials, electrical properties of LEDs, and chromaticity coordinates of luminous colors are analyzed and discussed.

Enhancing fucoxanthin production in Chaetoceros calcitrans under mixotrophic condition and LED wavelength shift strategy

This study addresses the challenge of achieving high fucoxanthin (Fx) productivity in Chaetoceros calcitrans under mixotrophic cultivation which often struggle to simultaneously increase biomass and Fx content. To overcome this, we investigated the potential of C. calcitrans for Fx production under mixotrophic conditions by investigating the interaction of organic carbon, light intensity, and light emitting diode (LED) color shifts during cultivation to optimize Fx production. Results revealed significant influences of various organic carbon sources on Fx productivity, with glycerol and glucose showing promising outcomes. Furthermore, the addition of external urea enhanced Fx content in mixotrophic cultivation. Response Surface Methodology (RSM) analysis highlighted the synergistic effect of light intensity and glycerol addition on Fx productivity. Most notably, shifting from white to blue LED during mixotrophic cultivation at the end of the exponential phase significantly increased Fx productivity in C. calcitrans to 3.2 mg L−1 d−1, representing a 1.3-fold enhancement compared to white LED sources. These findings underscore the potential of mixotrophic cultivation and LED color shifts as effective strategies for improving Fx productivity in diatoms.

Combined effect of LED light color and nitrogen source on growth, pigments composition and oxidative stress in Arthrospira platensis

Artificial lighting with light-emitting diodes (LED) is proposed as a suitable solution to reach stable yearly production of high value molecules from microalgae under unfavorable climates. However, available studies are inconsistent regarding the effect of LED color on cultures performance. This study examined the response of Arthrospira platensis to three different LED lighting conditions (white, red, and red-blue 70:30) when is grown in three media with different nitrogen composition. Growth, phycobiliproteins and lipophilic pigments content were determined. In addition, antioxidant enzymes (GST, lipid peroxidation) and morphology were analyzed to enlighten new perspectives on the health status of microalgae production.The highest biomass production (2.13 g/L) was achieved under red LED when Zarrouk medium was supplemented with urea. Regarding pigment production (phycobilins, chlorophyll a and β- carotene), the most desirable combination was red: blue together with urea supplementation. In addition, this combination showed a high biomass production (2.03 g/L) and low expression of antioxidant enzymatic activity. This research shows a novel combination of LED technology and nutrients to enhance microalgae biomass production and high value metabolites with a lower economic cost.

Asymmetric supercapacitor device fabrication of pristine Zeolitic Imidazolate Framework-67 with ultrahigh performance and cyclic stability

Employing a simple stirring and cost-effective approach, the pristine Zeolitic Imidazolate Framework-67 (ZIF-67) material is prepared and utilized as an electrode in three- and two-electrode (asymmetric device) configurations. The synthesized material exhibits well-defined rhombic dodecahedral morphology, noteworthy porosity, and a high specific surface area (1109.54 m2g−1). In the three-electrode configuration, the electrochemical study reveals a high specific capacitance (CS) of 377.8 Fg−1 and an outstanding cyclic stability (118.2 %) in a 6 M NaOH aqueous electrolyte. Furthermore, a device with a voltage window of 1.2 V was built employing a positive electrode (ZIF-67) and a negative electrode of activated carbon (AC). Interestingly, the ASSC demonstrated a maximum device-specific capacitance (CS) of 222.40 Fg−1, high energy density (ED) of 21.45 WhKg−1, and the highest power density (PD) of 3231.07 Wkg−1. Afterward, the ASSC device demonstrated remarkable cyclic stability (178.7 %) over 4000 constant galvanostatic charge/discharge (GCD) cycles. Different colors of LEDs (Light Emitting Diodes) and their series combinations are lightened using three devices (connected in series). As a result of the exceptional presentation of ZIF-67, it acts as a possible choice for energy storage devices.

Intermolecular interaction-controlled novel azo dyes for use in the high-performance color conversion layers of microdisplays

We synthesized four novel red azo dyes for use in a low-temperature-cured white organic light-emitting diode color conversion layer. The various substituents were introduced into the synthesized dyes to induce steric strain within the base compound for enhancing their solubility. All synthesized dyes exhibited excellent maximum absorption peaks at 521 nm, and AR4, in particular, displayed the highest molar absorptivity of 42 500. Via optimal mixing, the synthesized dyes were used to form red color resists for use in microdisplay color conversion layers. As a white backlight was applied to the optimized spin-coated films, the AR3 and AR4 films, with large dihedral angles between their substituents and diazonium planes, exhibited excellent color coordinates and transmittances, as intermolecular aggregation was inhibited. The color resists fabricated using the AR3 and AR4 dyes also displayed clear micropatterning results, confirming their high compatibility with low-temperature curing binders for use in future display production.

Electrochemical performance investigation of different shaped transition metal diselenide materials based symmetric supercapacitor with theoretical investigation

Transition metal diselenide-based electrodes for hybrid symmetric supercapacitors appear as trending materials. Thereby in this paper, we report the preparation of different-shaped transition metal diselenides using a single-step hydrothermal route. The impact of the different morphology of the prepared transition metal diselenide material has been studied on their electrochemical performance. The nanoflower-shaped MoSe2 material was observed to deliver the highest electrochemical result than nanoneedles and nanospheres shape of CoSe2 and NiSe2 material respectively. The highest specific capacitance delivered by the MoSe2 material-based symmetric supercapacitor was 154 F g−1 at 10 mV s−1. It also exhibits a maximum energy density of 17 Wh kg−1 with 1267 W kg−1 power density. Further, the MoSe2-based symmetric supercapacitor has been utilized to burn different colors of light-emitting diodes along with a panel of 26 LEDs of red color. To make the working of the symmetric supercapacitor (MoSe2-based) easier to understand for the readers we have proposed a mechanism of charge storage associated with it. Additionally, the experimental finding has been supported by investigating the structural and electronic properties of MoSe2, CoSe2, and NiSe2 via density functional theory calculation.

The colour temperature and placement of LED lighting near rivers can reduce attraction of flying adult caddisflies

Abstract Artificial light at night (ALAN), which can confuse and distract insects, has been implicated as a contributor of their decline worldwide. Changes in artificial light technology has led to a widespread conversion of outdoor lighting to light‐emitting diode (LED) bulbs, which are more energy efficient than older high‐intensity discharge or fluorescent lamps. However, many outdoor LED lights emit a proportion of short‐wavelength blue light, to which insects are commonly sensitive. The potential to reduce flying insect attraction to outdoor lights by using LEDs that emit different amounts of blue light, or by placing lights further from insect sources has not been well‐studied, particularly for freshwater insects. We tested whether four blue‐white LEDs that varied in their emittance of blue light intensity (3000, 4000, 5650, 6500 Kelvin [K] colour temperature) differed in their attractiveness to flying insects, particularly adult caddisflies (Trichoptera) over distances up to 100 m from a river. LEDs were deployed at a lit urban river and a predominantly unimpacted braided river in Canterbury, New Zealand. We expected a greater abundance and species richness of adult caddisflies to be attracted to LEDs that emit more blue light (cooler white LEDs [6500, 5650 K]) than those that emit less (warmer colour temperatures [3000 K, 4000 K]). We also expected the abundance and species richness of adult caddisflies in light traps to decline rapidly with increasing distance from the river, regardless of colour temperature. Moths, flies and a total of 26 caddisfly species were collected from both rivers. Significantly more caddisflies were attracted to higher than lower colour temperature LEDs. For example, a more than 1.6‐fold number of caddisflies were caught by the bluer‐white 6500 K LEDs than the warmer‐white 3000 K LEDs. This trend was consistent across most caddisfly taxa and both rivers. The number of caddisflies attracted to LEDs significantly declined with increasing distance from the river edge for the two most abundant caddisfly families and the four most abundant species; 65% of all caddisflies were caught by 20 m from the river margin. In order to reduce the attraction of caddisflies to outdoor lights such as streetlights, our study highlights the importance of considering a low LED colour temperature (3000 K or 4000 K) or those that emit less blue light and the benefit of positioning lights further back from waterways, where possible. Our results indicate that plans for urban outdoor lighting should consider the ecological implications of different colour temperature LEDs and their spatial position as project design considerations.

Spirulina Cultivation Under Different light-emitting Diodes for Boosting Biomass and Protein Production.

Microalgae biomass and pigments have a high economic value due to their many biological and commercial applications. In this sense, Spirulina platensis was grown under different (LEDs) light-emitting diodes. The current examination aims to increase the biomass production of S. platensis by formulating an optimal growth condition under different LED lights. Light-emitting diodes have a precise wavelength that has an encouraging effect on microalgae biomass production. For this purpose, the light intensity of 3000lx was used to illuminate the culture medium, resulting in enhanced S. platensis biomass production. The highest optical density of 0.576 and dry cell weight of 0.343g/L was recorded for the white light-emitting diode, and the red light-emitting diode, the optical density of 0.479 and dry cell weight of 0.321g/L was recorded. The highest protein content of 66.10 ± 0.44% was registered with a blue light-emitting diode, followed by a white light-emitting diode with a protein content of 60.86 ± 0.39%. This research is an essential step in defining the light condition that might be useful to increase the biomass production of S. platensis. The study's findings demonstrated that exposure to various light-emitting diode colors could enhance both the quality and quantity of biomass produced in S. platensis cultures and encourage the use of light-emitting diodes as a light source for S. platensis farming without any undesirable effects on growth.

Construction of high performance aqueous asymmetric supercapacitor based on multi walled carbon nanotube/MgMn2O4 composite

MgMn2O4 nanoplates like structure are synthesized by fast and easiest co-precipitation method. The end product is figured out by numerous characteristic techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), field emission electron microscope (FESEM), selected area electron diffraction (SAED) and Brunauer-Emmett-Teller (BET) surface area analysis. Further, the nanostructure material is subjected as electrode material for energy storage performance. The specific capacitance of 821 F g−1 is observed at 1 A g−1 from MgMn2O4 nanoplates. The specific capacitance of prepared MgMn2O4 nanomaterial is further boosted by small amount of multi walled carbon nanotubes (MWCNTs) and, high specific capacitance of 1208 F g−1 is observed at 1 A g−1 from MWCNT/MgMn2O4 composite. Furthermore, the aqueous asymmetric supercapacitor (ASC) is constructed where MWCNT/MgMn2O4 is used as positive electrode and activated carbon (AC) is used as negative electrode. The ASC device reveals the high energy density of 54.39 W h kg−1 with power density of 775.46 W kg−1 at 1 A g−1. Furthermore, two parallel connected red color light-emitting diodes (LEDs) are lit by series connected two ASCs. In addition, a kitchen timer and toy motor fan are also powered by series connected two ASCs. The enhanced supercapacitive performance of composite material is ascribed to the surface roughness of nanoplates, where small voids on the surface of the nanoplates provide more accommodation for electrolytic ions, and connectivity of nanoplates through MWCNTs provide suitable electronic path for electrons/ions during charging/discharging process. This attractive performance reveals that MWCNT/MgMn2O4 may be considered as prospective electrode material for high energy storage performance of supercapacitors.

The use of LEDs as a light source for fluorescence pressure measurements

ABSTRACT We discuss the use of commercial high power light emitting diodes (LEDs) as a light source for fluorescence pressure measurements. The relatively broad light emitting spectra of single color LEDs (in comparison with lasers) do not prevent producing narrow fluorescence lines at least for two widely used pressure indicator materials, namely ruby () and strontium tetraborate (). Strongest responses of both pressure gauges were detected for the green color LEDs with the average wavelength . LEDs might be easily implemented for producing fiber-coupled, as well as the parallel light sources. LEDs were found to be efficient to replace laser sources in piston-cylinder cell and diamond anvil cell fluorescence pressure measurement setups.

Fast Neutron Irradiation on GaN-Based Light-Emitting Diodes From Near-Ultraviolet to Green Spectral Ranges

Neutron irradiation effects were compared for GaN-based multi-quantum well (MQW) light emitting diodes (LEDs) with emission wavelength in the near-ultraviolet (NUV), blue and green spectral regions. Optical output power, current-voltage and peak wavelength were analyzed in detail before and after irradiation. Three colors of LEDs showed an increase and then a decrease in optical output power with the increase of neutron fluence ranging from 1.0×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> to 1.0×10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">14</sup> cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-2</sup> . The enhanced light emission performance is attributed to the increase of carrier injection for neutron irradiated MQWs. In addition, the formation of tunneling conductivity channels in the p-doped AlGaN electron block layer (EBL) induced by neutrons is considered as the main factor that dominates the performance degradation. Among the three colors of LEDs, the order of severity for the optical and electrical properties influenced by this medium-fluence neutron irradiation is green, blue, and NUV LEDs, in turn becoming more serious. The NUV LEDs rely heavily on the EBL due to their poor carrier confinement in relatively shallow GaN/AlGaN MQWs, so an increase of carrier injection or leakage induced by neutrons has significant influence on device performance. As the green LEDs have deep quantum wells, the strong confinement of carriers leads to their being least sensitive to neutron irradiation. So we believe that design of LEDs with deep quantum wells to enhance the carrier confinement ability will be helpful to improve their radiation tolerance. The findings not only enrich the understanding of the influence mechanism of neutron irradiated GaN-based UV/visible LEDs, but are also helpful to radiation hardened design.

NiO/g-C3N4/PANI/Ni-metal-organic framework composite for high-energy supercapacitor electrodes

This work is prioritized in tuning the capacitive performance of nanostructured nickel-metal-organic framework (Ni-MOF) as a high-performance electrode material for supercapacitors. The enhancement in performance is conducted by choosing a material combination that includes a metal oxide, carbonaceous, and conductive polymer comprising nickel oxide/graphitic carbon nitride/polyaniline. The material coupling is carried out by a simple reflux method using benzene-1,4-dicarboxylic acid as an organic ligand. Various characterization tools are used to confirm structural, chemical, electronic, thermal, and morphological properties. The tuned quaternary composite, nickel oxide/graphitic carbon nitride/polyaniline/Ni-MOF, exhibited a battery-type storage mechanism delivering a high specific capacitance (specific capacity) of 2,420 F/g (584 mAh/g) at the current density of 5 A/g, with a specific capacitance retention ability of 75% at 20 A/g. A kinetic study using a rotational disk electrode is carried out, and the highest diffusion coefficient of 8.64 × 10−9 cm2/s is obtained. In the fabrication supercapacitor, the quaternary composite delivered an energy density of 31.3 Wh/kg at a power density of 1,491 W/kg. It was found to be 1.5 times more than the ternary-based supercapacitor. Finally, stability tests were carried out, and the fabricated supercapacitors reached 99.5% stability even after 3,000 charges and discharges. For practical application demonstration, Swagelok cells are manufactured and charged to glow with different color light-emitting diode lights. This work brings a clear path to developing MOF-based composites for high-energy storage applications.

Green synthesis silver nanoparticles Bougainvillea glabra Choisy/LED light with high catalytic activity in the removal of methylene blue aqueous solution.

In this study, we evaluated, in a pioneering way, the influence of wavelengths from the decomposition of white light on the production and physicochemical properties of silver nanoparticles (AgNPs). Bearing in mind a process of green synthesis, an extract of the bracts of Bougainvillea glabra Choisy (BgC) was used, a species native to tropical and subtropical regions and frequently used in ornamentation, possessing in its photochemical composition, biomolecules capable of acting as reducing agents for convert Ag+ to Ag0. We used light-emitting diodes (LED) to obtain the desired wavelengths (violet, blue, green, yellow, orange, and red) in the test called rainbow, and we evaluated the obtaining of AgNPs compared to white LED light, nature, and absence of light. In the rainbow assay, we obtained a gradual increase in the intensity of the plasmonic band resonance from the red wavelength (0.124 ± 0.067 a.u.) to violet (0.680 ± 0.199 a.u.), indicating a higher reaction yield in obtaining AgNPs. Smaller hydrodynamic sizes (approximately 150nm) at more energetic wavelengths (violet, blue, and green) about less energetic wavelengths (yellow, orange, and red) (approximately 400nm) were obtained. Analysis by SEM microscopy, FTIR spectroscopy, and X-ray diffraction indicates the presence of silver nanoparticles in all LED colors used together with white LED light and Laboratory light (natural light). Due to the high environmental demand to remove pollutants from water sources, including textile dyes, we applied AgNPs/BgC to remove methylene blue (MB) dye from an aqueous solution. A minimum removal percentage greater than 65%, with emphasis on formulations synthesized by the colors of violet LED (84.27 ± 2.65%) and orange LED (85.91 ± 1.95%), was obtained.

A graphene/carbon black nanofluidic membrane with fast ion transport for enhanced electrokinetic energy generation

Harvesting energy from transport of water and ions at ambient environment is promising towards sustainable perspective, yet an easy-fabrication and high-performance water-enabled energy generation device remains largely unexplored. Herein, we report a simple method to fabricate a 2D/0D graphene/carbon black (GCB) nanofluidic membrane for high-performance electrokinetic energy generation (EKEG), driven by capillary action and water evaporation. The results obtained suggest that the GCB membrane features enhanced ion transport, owing to the synergistic effects of horizontally oriented 2D confined channels, highly conductive graphene, and high surface charge of GCB. Therefore, dropping 100 μL of natural seawater on one side of a GCB nanofluidic membrane is capable of achieving a considerable current of ∼121 μA and a voltage of ∼0.49 V at ambient environment (25 ± 1 °C and 55 ± 5% relative humidity), surpassing the state-of-the-art evaporation-driven EKEG devices. More amazingly, connecting ten GCB membranes in parallel can produce an ultrahigh current at the mA level. Applications in lighting up various colors of light-emitting diodes and powering electronics are demonstrated as well. This work paves new avenues for next-generation high-performance water-enabled electrokinetic energy generators.