Vivid Colors Research Articles

Red Beetroot and Its By-Products: A Comprehensive Review of Phytochemicals, Extraction Methods, Health Benefits, and Applications

Beetroot (Beta vulgaris), a root vegetable known for its vivid natural color and nutritional profile, is a source of a wide range of bioactive compounds, including betalains, phenolics, vitamins, and antioxidants. These bioactive compounds are associated with many health-promoting properties, including antihypertensive, antioxidant, anti-inflammatory, and anticancer effects. The beetroot processing industry produces substantial by-products abundant in phytochemicals and betalains, presenting valuable opportunities for utilization. Therefore, it can replace synthetic additives and enhance the nutritional value of foods. By reducing waste and supporting a circular economy, beetroot by-products improve resource efficiency, cut production costs, and lessen the food industry’s environmental impact. Beetroot and its by-products are rich in phytochemicals that provide various wellness advantages. They support cardiovascular health, inhibit microbe-induced food spoiling, aid liver function, and reduce inflammation and oxidative stress. This paper presents a detailed review of current knowledge on beetroot and its by-products, focusing on their biochemical components, extraction and stabilization techniques, health benefits, and potential applications in the food industry. It underscores the versatility and importance of red beetroot and its derivatives, advocating for further research into optimized processing methods and innovative uses to enhance their industrial and nutritional value. By providing valuable insights, this review aims to inspire food scientists, nutritionists, and the agricultural sector to integrate beetroot and its by-products into more sustainable and health-oriented food systems.

Metabolomics Combined with Transcriptomics Reveals the Formation Mechanism of Different Colored Flowers of Cosmos bipinnata Cav

In nature, plants have rich and vivid colors. Flower color can confer economic and ornamental value to ornamental plants, and is one of the target traits for current directed breeding. Therefore, it is essential to understand the molecular regulatory mechanisms behind flower color formation in ornamental plants. However, in Cosmos bipinnata Cav., one of the most important ornamental plants, the metabolic pathways and molecular regulatory mechanisms underlying the formation of different flower colors are not yet clear, which greatly restricts the molecular breeding of flower color varieties. We selected three varieties of Cosmos bipinnata Cav. with white, pink, and red flowers as research materials, and identified significantly different metabolites among them through ultra performance liquid chromatography mass spectrometry (UPLC-MS/MS) analysis and principal component analysis (PCA). Then, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and transcriptome sequencing analysis in different colors flowers were used to reveal that the differential metabolites were enriched in flavonoid metabolic pathways and related structural genes were differentially expressed. Furthermore, we identified differentially expressed members of the MYB and bHLH transcription factor families, which play key roles in regulating the anthocyanin biosynthesis. By constructing a phylogenetic tree and performing a joint analysis of transcriptome and metabolome data, we further elucidated the molecular regulatory network underlying the formation of flower colors in Cosmos bipinnata Cav. This study not only provides a theoretical basis and gene resources for color-oriented breeding and the creation of new color varieties, but also offers new insights into the molecular mechanisms of flower color formation in plants.

Scalable and Precise Synthesis of Structurally Colored Bottlebrush Block Copolymers: Enabling Refined Color Calibration for Sustainable Photonic Pigments.

Self-assembled bottlebrush block copolymers (BBCPs) offer a vibrant, eco-friendly alternative to traditional toxic pigments and dyes, providing vivid structural colors with significantly reduced environmental impact. Scaling up the synthesis of these polymers for practical applications has been challenging with conventional batch methods, which suffer from slow mass and heat transfer, inadequate mixing, and issues with reproducibility. Precise control over molecular weight and dispersity remains a significant challenge for achieving finely tuned color appearances. Here, we present an alternative strategy to overcome the challenges by integrating a rapid continuous flow technique with an in-line self-assembly procedure. This strategy enables the rapid, stable and large-scale synthesis of narrow-dispersed BBCPs, exceeding 2 kg/day, a significant improvement over conventional gram-scale methods. Furthermore, precise control over the degree of polymerization is achieved with an unprecedented interval accuracy of four repeat units. This level of precision enables refined color calibration in the resulting photonic pigments, effectively eliminating the need for labor-intensive and costly multiple batch syntheses.

Scalable and Precise Synthesis of Structurally Colored Bottlebrush Block Copolymers: Enabling Refined Color Calibration for Sustainable Photonic Pigments

Self‐assembled bottlebrush block copolymers (BBCPs) offer a vibrant, eco‐friendly alternative to traditional toxic pigments and dyes, providing vivid structural colors with significantly reduced environmental impact. Scaling up the synthesis of these polymers for practical applications has been challenging with conventional batch methods, which suffer from slow mass and heat transfer, inadequate mixing, and issues with reproducibility. Precise control over molecular weight and dispersity remains a significant challenge for achieving finely tuned color appearances. Here, we present an alternative strategy to overcome the challenges by integrating a rapid continuous flow technique with an in‐line self‐assembly procedure. This strategy enables the rapid, stable and large‐scale synthesis of narrow‐dispersed BBCPs, exceeding 2 kg/day, a significant improvement over conventional gram‐scale methods. Furthermore, precise control over the degree of polymerization is achieved with an unprecedented interval accuracy of four repeat units. This level of precision enables refined color calibration in the resulting photonic pigments, effectively eliminating the need for labor‐intensive and costly multiple batch syntheses.

Exploring and analyzing the causes of color in the earth

Color is an essential element of human visual perception, which exists in all aspects of our daily lives and plays a key role in scientific research and technological applications. Color is produced by various mechanisms, including absorption and reflection of chemical pigments, complex formation of transition metal ions, and micro- and nanostructural modulation of structural colors. This paper aims to comprehensively explore the scientific principles of color generation and its applications in different fields. The article first describes how transition metal ions exhibit colors by forming complexes and explains in detail the coordination process of copper ions in an aqueous solution and its resulting d-orbital splitting, which in turn absorbs light of specific wavelengths and exhibits complementary colors. Secondly, the article explores the mechanism of color expression of natural pigments in plants, significantly how pigment molecules containing conjugated double bonds, such as -carotene, can absorb specific wavelengths of light and exhibit vivid colors through electron delocalization and energy level jumps. Finally, the article illustrates the principles of structural color and its potential for industrial applications, including using micro- and nanostructures, such as photonic crystals, to modulate the scattering and absorption of light, thus enabling dynamic changes in color and environmental protection. The in-depth exploration of the mechanism of color generation enhances our understanding of the basic principles of color science. It provides theoretical support for technological innovation and practical applications in related fields.

Indoloindolizines: The Complete Story of a Polycyclic Aromatic Scaffold from Theoretical Design to Organic Field-Effect Transistor Applications.

The development of stable and tunable polycyclic aromatic compounds (PACs) is crucial for the advancement of organic optoelectronics. Conventional PACs, such as acenes, often suffer from poor stability due to photooxidation and oligomerization, which are linked to their frontier molecular orbital energy levels. To address these limitations, we designed and synthesized a new class of π-expanded indoloindolizines by merging indole and indolizine moieties into a single polycyclic framework. We developed a scalable synthetic protocol to produce a wide range of π-expanded derivatives. The structural, electronic, and optical properties of these compounds were extensively characterized. We achieved precise modulation of the electronic structure by controlling the aromaticity of specific rings. Benzannulation at targeted positions allowed fine-tuning of the HOMO-LUMO gap, leading to distinct shifts in the optoelectronic properties. Single-crystal X-ray diffraction confirmed their molecular structures, while theoretical calculations provided insights into the observed experimental trends. These indoloindolizines exhibit vivid colors and fluorescence across the visible spectrum and enhanced stability against photooxidation. Reactivity studies demonstrated high regioselectivity in electrophilic substitutions, highlighting the indole-like behavior of these compounds and opening avenues for further functionalization. To showcase the practical utility of our design rules, we fabricated organic field-effect transistors (OFETs) using the newly developed indoloindolizines, which revealed remarkable performance with ambipolar charge transport properties. Overall, our work establishes indoloindolizines as a promising platform for the development of stable, tunable organic materials for optoelectronic applications. Through rational molecular design, we have provided a new pathway for molecular innovation in organic electronics.

Narrowband emission and enhanced stability in top-emitting OLEDs with dual resonant cavities.

Capping layers (CPLs) are commonly employed in top-emitting organic light-emitting diodes (TEOLEDs) due to their ability to optimize color purity, enhance external light out-coupling efficiency, and improve device stability. However, the mismatch in refractive index between CPLs and thin film encapsulation (TFE) often induces light trapping. This study introduces a novel approach by combining a low refractive index material, lithium fluoride (LiF), with the traditional TFE material, silicon nitride (SiNx), to form a combined CPL (LiF/SiNx), resulting in improved light outcoupling and light reflection properties. The significant refractive index contrast between LiF and SiNx can facilitate enhanced light extraction by redirecting internally reflected light through evanescent waves. Moreover, the LiF/SiNx CPLs function as a secondary resonant cavity, leading to reduced emission spectral bandwidth and enhanced light extraction compared to the control TEOLEDs that only incorporate the primary cavity of organic active layers. As a result, incorporating the LiF/SiNx CPLs significantly increases current efficiency from 125.0 cd A-1 to 163.6 cd A-1 for green devices, from 71.2 cd A-1 to 110.1 cd A-1 for red devices, and from 43.1 cd A-1 to 53.1 cd A-1 for blue devices, with the corresponding full width at half maximum decreased from 20 nm to 10 nm, 26 nm to 14 nm, and 21 nm to 12 nm, respectively, demonstrating the compatibility of the CPLs with different color devices. Notably, an LT95 lifetime of 51 300 hours for green devices was achieved when tested at 1000 cd m-2. Utilizing narrow-band light emission without spectral overlap of each color enables the generation of purer and more vivid colors for display.

Multicolored Bifacial Perovskite Solar Cells through Top Electrode Engineering.

Power generation and architectural beauty are equally important for designing efficient and esthetically appealing bifacial perovskite solar cells (PSCs). In this work, efficient and multicolored p-i-n-structured PSCs are achieved by taking advantage of a dielectric/metal/dielectric (DMD)-type (MoO3/Ni/Ag/MoO3) transparent counter electrode. The MoO3/Ni underlayer effectively promotes the formation of a continuous and conductive ultrathin Ag transparent film, especially the 1 nm Ni seed layer adjusts the interface energy level between perovskite/MoO3 and Ag, resulting in Ohmic contact of the electrode to promote charge extraction and collection. The upper MoO3 layer with varied thicknesses realizes a spectrally selective antireflection coating, enhancing the rear-side efficiency and forming vivid rear-side colors by optical tuning. As a result, colorful bifacial perovskite solar cells with 20.6% front-side efficiency and 57.6-74.4% bifacial factor are obtained together with colorful rear-side appearance. The bifacial PSCs exhibit good stability by protection from the upper MoO3 layer. This work highlights an effective electric and optic design of the top electrode for artistic bifacial PSCs.

Preparation of colorful glass/W/V2O5 electrochromic electrodes by magnetron sputtering

Abstract V2O5, an inorganic electrochromic (EC) material with rich color variation and natural abundance, has received extensive attention due to its polychromatic properties during the EC process. However, research on achieving multicolor tuning by combining the structural color generated from the light-matter interactions with the EC properties of V2O5 is rare. Here, based on the detailed investigation of the process parameters of V2O5, we propose a new optical design of the colorful EC electrode with the V2O5/W Fabry–Pérot cavity constructed by magnetron sputtering on the glass substrate. By varying the thickness of the top layer of V2O5, the reflective electrodes exhibit seven different initial colors. Importantly, the designed EC electrode exhibits a vivid and rich wide color gamut when applying a voltage of −0.6–1.6 V. After 200 cycles, the color of the EC electrode and device can still change, demonstrating the potential of the glass/W/V2O5 EC electrodes in the fields such as camouflage and anti-counterfeiting.

CRISPR/Cas12a-Enabled Amplification-Free Colorimetric Visual Sensing Strategy for Point-of-Care Diagnostics of Biomarkers.

CRISPR/Cas12a-based biosensors have garnered significant attention in the field of point-of-care testing (POCT), yet the majority of the CRISPR-based POCT methods employ fluorescent systems as report probes. Herein, we report a new CRISPR/Cas12a-enabled multicolor visual biosensing strategy for the rapid detection of disease biomarkers. The proposed assay provided vivid color responses to enhance the accuracy of visual detection. In the existence of the target, the trans-cleavage activity of CRISPR-Cas12a was activated. The report probe modified with magnetic beads (MBs) and horseradish peroxidase (HRP) was cleaved, and HRP was released in the supernatant. As a result, HRP mediated the etching of gold nanobipyramids (AuNBPs) under hydrogen peroxide and 3,3',5,5'-tetramethylbenzidine and generated a vivid color response. The proposed method has been verified by the detection of the breast cancer 1 gene (BRCA1) as a proof-of-principle target. According to the different colors of AuNBPs, our experimental results have demonstrated that as low as 30 pM BRCA1 can be detected with no more than 60 min. Additionally, the proposed sensor has been successfully applied in the analysis of BRCA1 in human serum samples with satisfactory results, which indicates great potential for the sensitive determination of biomarkers and the POCT area.

Iridescent structural color by using ultra-low refractive index aerogel as optical cavity dielectric

Iridescent color-shift pigments have been used in some industrial applications, e.g., for cosmetics and packaging. To achieve environmental-friendly and lasting color, thin-film interference is used to generate structural color. By maximizing the refractive index (RI) difference between the thin films (i.e., using an ultralow RI film), super-iridescent structural color can be produced. While the lowest refractive index of a naturally occurring solid dielectric is close to 1.37 (i.e., MgF2), we synthesized highly porous dielectric SiO2 aerogel to achieve ultralow-RI (n ~ 1.06) and demonstrated a high-refractive index/low-refractive index/absorber (HLA) trilayer structural color. The achieved structural color is highly iridescent and capable of tracing a near-closed loop in CIE color space. By tuning the refractive index, thickness, and geometry of the aerogel layer, we control the reflection dip’s shape, therefore producing a wide range of vivid and iridescent colors.

Spatiotemporal Retention of Structural Color and Induced Stiffening in Crosslinked Hydroxypropyl Cellulose Beads.

Hydroxypropyl cellulose (HPC) is known for its ability to form cholesteric liquid crystalline phases displaying vivid structural colors. However, these vibrant colors tend to fade over time when the material dries. This issue is a major bottleneck to finding practical applications for these materials. Here this problem is overcome by producing free-standing, millimeter-sized HPC structurally colored beads with spatiotemporal color retention, facilitated by a glutaraldehyde crosslinker. By leveraging the well-known chemically induced stabilization of cholesteric liquid crystalline phases, stable structural colors are achieved for at least three weeks. The presence of glutaraldehyde significantly increases the mechanical stiffness, with Young's modulus rising from 0.3± 0.1GPa to 1.8± 0.2GPa. This integrated approach of creating free-standing photonic HPC beads offers a strategy for developing robust and durable photonic HPC materials with enhanced stability, advancing photonic material applications with spatiotemporal color stability.

Visualization of strain rate based on mechanoluminescence tailing

Mechanoluminescence (ML) materials have the ability to emit light under mechanical force, allowing for visible mechanical force distribution and making them valuable for applications in smart textiles and wearable sensors. Detecting the force rate is crucial for applications, such as haptic feedback devices and mechanical monitoring, but visualizing the speed of strain has not been achieved yet. In this study, we have successfully visualized the strain rate by monitoring the ML tailing lengths of red, green, and blue (RGB) ML materials, including CaF2: Tm3+, CaF2: Eu3+, and CaF2: Tb3+ phosphors. These materials exhibit varying ML tailing lengths at identical rotation speed of friction force, due to their distinct lifetime of the emitting centers. By incorporating these RGB ML phosphors into a composite film, the discrepancies in ML tailing lengths across different colors become visible, with these differences becoming more pronounced as the rotation speeds rise. Ultimately, the visualization of rotational speed in bearings was achieved successfully based on the vivid color changes in the ML tailing length at different speeds.

Cellulose nanofibers/polyacrylic acid hydrogels integrated with a 3D printed strip: A platform for screening prostate cancer via sarcosine detection.

Cellulose nanofiber/polyacrylic acid (CNF/PAA) hydrogel-based colorimetric sensor was fabricated for non-invasive screening of prostate cancer (PCa) via selective detection of sarcosine. The hydrogel was synthesized by photo-crosslinking of acrylic acid in the presence of CNF which acted as mechanical reinforcement and as color enhancer. The hydrogel exhibited a high aqueous absorption and high mechanical strength. A homogeneous distribution of CNF in the hydrogel was confirmed by TEM. A significant improvement in the compressive modulus and stress in the hydrogel were obtained after the incorporation of 0.25%wt CNF. The hydrogel sensor was integrated within a 3D printing strip on a diaper, and it offered a vivid color change from light yellow to blue for detecting sarcosine for PCa indication with a detection limit starting from 10μM. The colorimetric results were semi-quantitatively evaluated by a spectrophotometer offering a linear range of 0-100μM with R2 of 0.9901. Furthermore, the increase in CNF content significantly enhanced the sensor's sensitivity toward sarcosine. This sensor could open new avenues for non-invasive screening of prostate cancer in the future.

Simple Preparation of Au Nanoparticles by Arc Plasma Deposition (APD) and Its Application for SERS Sensing

Nanoparticles express many beneficial properties. For examples, large specific surface area and high catalytic activity. These properties are used in fuel cell catalysis and other applications such as biosensing since porous nanoparticles have a high adsorption area for substances. Nanoparticles for biosensing technology are used to not only bind with biomolecules but also observe the behavior of the biomolecules, such as cells. In this study, we focused on Au nanoparticles with plasmon resonance, i.e., one of the optical properties. When metal nanoparticles, such as Au or Ag, are irradiated with light, free electrons of metal nanoparticles are affected by the electric field of the light and cause plasmon resonance, which produces a unique optical phenomenon. On the plasmon resonance, the light with a specific wavelength is strongly absorbed and scattered, resulting in vivid colors in the near-infrared range. This phenomenon is called Localized Surface Plasmon Resonance (LSPR). This phenomenon is used in sensors (to detect changes in refractive index and use as markers) as well as Surface-Enhanced Raman Scattering (SERS), which is used to evaluate material identification. In this study, we focused on SERS sensing. SERS is powerful tool to identify and quantify the materials since Raman spectrum reflect chemical bonds of substances and concentration. Because Raman spectrometers can non-destructively measure substances through glass, bags, or opaque containers, they are used to investigate explosives, toxic chemicals, and other counter-terrorism measures. Therefore, a SERS sensor with a simple fabrication process is required.There are two methods for producing the nanoparticles: a physical method (pulverization method), and a chemical method (agglomeration method). Physical methods create nanoparticles by crushing powder, but it is difficult to control the particle size. By contrast, chemical methods can be mainly classified into wet methods and dry methods. The wet method is reducing ions in liquid therefore it requires waste liquid treatment, which places a burden on the environment. Therefore, we focused on Arc Plasma Deposition (APD), which is one of dry methods and a low environmental impact. APD allows nanoparticles to be easily produced in one step. Nanoparticles were fabricated using APD and applied to SERS sensor. APD can control the deposition molecules by digital, meaning the number of pulses. The parameters of APD are capacitance of trigger capacitor, applied voltage, the number of pulses, and substrate temperature. At first, we investigated its vapor deposition characteristics when the substrate temperature is kept at room temperature.The amount of deposited molecules is proportional to the square of the discharge voltage (V), directly proportional to the capacitance (C), and dependent on the number of pulses (n) :(E=1/2×nCV2). Applied volage was ragged from 70 to 100 V, a capacitance was set as 2200 μF, and the number of pulses were from 5 to 80 times. The pressure during vapor deposition was 1.3×10-3 Pa. The average particle diameter and coverage ratio were calculated by observing the prepared sample via a Scanning Transmission Electron Microscope (STEM). It was clear that particle diameter and coverage ratio increased with the applied voltage and the number of pulses. We evaluated the fabricated sensor exhibited SERS activity using rhodamine 6G (R6G), a fluorescent substance. In this study, we evaluated analytical enhancement factor (AEF) to quantify our SERS The experimental results show that theAEF was determined as 2.13×10³. We also created a calibration curve for R6G ranging from 10-7 to 10-4 M. As the results, R6G-derived peaks were not identified at 10⁻⁷ M, but we identified them from 10-6 to 10-4 M (Fig. 1) and were able to create the linear calibration curve. Figure 1

A Computer Vision‐Based Methodology to Estimate Fruit Colour Diversity in Ornamental Pepper (Capsicum spp.)

ABSTRACTFruit colour diversity within different ripening stages confers ornamental value for pepper plants. Using images can be helpful in analysing the fruit colour‐related genetic diversity and enable selecting accessions for ornamental purposes by avoiding subjectiveness. This study aimed to evaluate the phenotypic diversity among accessions of ornamental pepper using image processing techniques to identify fruit colours. Photos from 40 fruits from each of 12 accessions were captured by a camera from a smartphone. Separate channels and colour indices were extracted from the images to analyse the accessions using both dendrogram and principal components analysis. Dendrogram analysis allowed separating accessions with predominance of dark fruits from those whose fruits showed lighter and more vivid colours, with a cophenetic correlation coefficient of 0.811. The VARI and NGRDI vegetation indices were efficient in discriminating fruits with a predominance of green colour, and the BGI could be used to discriminate accessions with predominantly reddish‐brown fruits. The proposed method can be used in small‐scale breeding programs for accurately assessing the development of varieties regarding their fruit colour diversity.

Flexible Inverse Opal Structural Color Films with High Strength and Harsh Environment Stability.

Flexible photonic crystals (PCs) constructed by PCs and special polymers are very promising to achieve a combination of vivid structural colors, mechanical robustness, and environment stability. However, PCs that incorporate polymer binders are still susceptible to destruction and subsequent loss of structural color when subjected to significant external forces or harsh environments. Besides, because most of these polymers are highly flammable, crucial fire safety is difficult to be guaranteed in the application of these materials. In this study, we report a poly(m-phenyleneisophthalamide) inverse opal (PMIA IO) structural color film through a SiO2 PC template sacrificing method. Benefiting from the high rigid PMIA molecular structural configuration, the PMIA IO films are able to maintain their structural colors even in harsh conditions, such as large tensile stress, high and low temperatures, potent acids and bases, and ultraviolet radiation. More attractively, the PMIA IO films demonstrate excellent flame retardancy, with the limiting oxygen index (LOI) and flame retardant rating reaching 28 vol % and V0, respectively. We believe that the flexible structural color films with high strength, harsh environment stability, and flame retardancy, which are difficult for other structural color materials to possess simultaneously, have great potential for special applications in fire protection, national defense, aviation, marine, and aerospace fields.

Structural Color of Partially Deacetylated Chitin Nanowhisker Film Inspired by Jewel Beetle.

Nanochitin was developed to effectively utilize crab shells, a food waste product, and there is ongoing research into its applications. Short nanowhiskers were produced by sonicating partially deacetylated nanochitin in water, resulting in a significant decrease in viscosity due to reduced entanglement of the nanowhiskers. These nanowhiskers self-assembled into a multilayered film through an evaporation technique. The macro- and nanoscale structures within the film manipulate light, producing vibrant and durable structural colors. The dried cast film exhibited green and purple stripes extending from the center to the edge formed by interference effects from the multilayer structure and thickness variations. Preserving structural colors requires maintaining a low ionic strength in the dispersion, as a higher ionic strength reduces electrostatic repulsion between nanofibers, increasing viscosity and potentially leading to the fading of color. This material's sensitivity to environmental changes, combined with chitin's biocompatibility, makes it well-suited for food sensors, wherein it can visually indicate freshness or spoilage. Furthermore, chitin's stable and non-toxic properties offer a sustainable alternative to traditional dyes in cosmetics, delivering vivid and long-lasting color.

Silicon rich nitride: a platform for controllable structural colors

Abstract High refractive index dielectric materials like silicon rich nitride (SRN) are critical for constructing advanced dielectric metasurfaces but are limited by transparency and complementary metal oxide semiconductor (CMOS) process compatibility. SRN’s refractive index can be adjusted by varying the silicon to nitride ratio, although this increases absorption, particularly in the blue spectrum. Dielectric metasurfaces, which utilize the material’s high dielectric constant and nano-resonator geometry, experience loss amplification due to resonance, affecting light reflection, light transmission, and quality factor. This study explores the impact of varying the silicon ratio on structural color applications in metasurfaces, using metrics such as gamut coverage, saturation, and reflection amplitude. We found that a higher SRN ratio enhances these metrics, making it ideal for producing vivid structural colors. Our results show that SRN can produce a color spectrum covering up to 166 % of the sRGB space and a resolution of 38,000 dots per inch. Fabricated samples vividly displayed a parrot, a flower, and a rainbow, illustrating SRN’s potential for high-resolution applications. We also show that SRN can provide a better CIE diagram coverage than other popular metasurfaces materials. These findings highlight the advantages of SRN for photonic devices, suggesting pathways for further material and application development.

Photovoltaic Performance of Naphthol Blue Black Complexes and their Band Gap Energy

Along with the depletion of petroleum-based fuels, the development of renewable energy resources is a must. One of them is through DSSC (Dye Sensitized Solar Cells) technology, which has a dye sensitizer and semiconductor as the main components. The aim of this research is to investigating the photovoltaic performance of complexes series from metals (Mn(II); Fe(II); Co(II) and Ni(II)) and naphthol blue-black (NB) as a ligand. This investigation also successfully revealed factors that are highly influencing photovoltaic efficiency, namely the band-gap energy and the conductance of metal-NB complexes. The Fe(II)-NB complex has performed the highest photovoltaic activity as a result of the d-d electron transition and MLCT (Metal to Ligand Change Transfer) character which are covered by vivid color from the ligand. The bonding between metal and ligand was shown at a wavenumber of 316.33 cm-1 for M-N bonding and 486.06 cm-1 for M-O bonding. Fe(II)-NB complex had the narrowest band gap energy which is 5.86 eV and had the highest value of conductance and the highest efficiency, namely 0.0925%. This experiment successfully demonstrates that the narrower the energy gap of a molecule, the ability to transfer electrons is faster. Thus, the efficiency of the solar cell becomes higher. This investigation has proven that the narrow band gap makes the electron transfer becomes easier.