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Two-step synthesis of reduced graphene oxide with columnar-shaped ZnO composites and their photocatalytic performance with natural dye
摘要： Composites of ZnO with reduced graphene oxide were prepared in two-step synthesis process with constant temperature in variation with pH values. The synthesized composites were characterized and the results suggest that ZnO structure in the composites has a columnar morphology with an average diameter ranging 0.8–1.57 μm. The obtained properties of the composites with the present method confirmed that the material morphology influences the absorption and photocatalytic activity of natural dye under sunlight irradiation. The result shows that the maximum degradation efficiency is 64.40% achieved in 120 min.
关键词： Zinc oxide,Columnar morphology,Photocatalytic activity,Reduced graphene oxide,Natural dye
更新于2025-09-23 15:23:52
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Effect of Dye Extraction Solvent on the Photovoltaic Performance of Tecoma stans-Sensitized Solar Cells
摘要： The use of natural dyes as photosensitizers has several advantages including their easy extraction and their biodegradable, nontoxic, and environmentally friendly nature, which makes them vital for application in dye-sensitized solar cells (DSSC). In the present work, we study the effects of extraction solvent on the photovoltaic performance of a natural dye sensitizer for TiO2-based DSSC. Extracts of Tecoma stans flowers in two different solvents, ethanol and ethanol–water mixture, were used as the dye sensitizer for extending the spectral sensitivity of TiO2. The optical properties of the dye extracts were studied by their UV–visible absorption spectra. Fourier transform infrared spectra revealed the presence of anchoring groups and coloring pigments, and nuclear magnetic resonance spectroscopy and mass spectrometry were used to characterize the main constituents of the dye extract. The photovoltaic characteristics of these dye extracts coated on TiO2 were investigated by employing them as DSSC photoanodes. With the dye extracted in ethanol and coated on TiO2, an open-circuit voltage (Voc) of 0.293 V, short-circuit photocurrent density (Jsc) of 0.790 mA/cm2, fill factor (FF) of 0.46, and conversion efficiency (g) of 0.13% were obtained, whereas dye extracted in the ethanol–water mixture revealed Voc of 0.285 V, Jsc of 0.735 mA/cm2, FF of 0.37, and g of 0.09%. The photovoltaic performance of the dye extracts in the two cases underlines the greater effectiveness of ethanol as dye extraction solvent.
关键词： natural dye,DSSC,rutin and zeaxanthin,Tecoma stans flower,TiO2,extraction solvent
更新于2025-09-23 15:21:01
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Citrus fruit peels extracts as light harvesters for efficient ZnO-based dye-sensitized solar cells
摘要： Our voracious consumption of fossil fuels at an exponentially increasing rate has led to global warming and climate change. As a result of these problems, it is crucial to explore other sources of clean energy. The natural pigments extraction and performance determination in Dye-Sensitized Solar Cells (DSSCs) from fruit peels of citrus were presented in this paper. Extraction of natural dye of citrus fruit peels of Citrus paradisi, Citrus sinensis, Citrus limonum and Citrus tangelo were employed as light sensitizers in fabricating ZnO-based DSSCs. The natural pigments extracts characteristics were analyzed by UV-Vis absorption, Fourier transforms infra-red (FTIR) and Photoluminescence spectroscopy techniques. The semiconductor active layer material was synthesized and analyzed. The characteristics of photo-voltaic parameters for the invented DSSCs were studied under simulated sunlight. The presence of chlorophyll derivative in most of the extracted dyes is evident as the core pigments with additional accessory pigments. The conversion efficiencies of sunlight to electrical energy of pheophytin 'a' dye ZnO based solar cells are calculated to be 0.028%, 0.013%, 0.004% and 0.022% for Citrus paradisi, Citrus sinensis, Citrus limonum and Citrus tangelo, respectively. Better performance of photo-sensitized was observed for the extracts of Citrus paradisi compared to the other extracts and this may be owing to the better charge transfer between the pigments of Citrus paradisi and surface of ZnO photoactive layer. The conversion of visible light to electricity was produced from natural pigments and ZnO photoactive layer based DSSCs, resulted into superb photo-electric characteristics.
关键词： chlorophyll derivative,Natural dye,citrus fruit peels,DSSC,conversion efficiency,photoactive layer
更新于2025-09-23 15:19:57
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Glycerin-based electrolyte for reduced drying of dye-sensitized solar cells
摘要： Dye-sensitized solar cells (DSSCs) are of high interest especially for applications on flexible or even stretchable substrates, such as architectural textiles. One of the main challenges for such use is the electrolyte which is usually fluid and thus leaks not only through porous textile structures, but also through the edges of common glass-based DSSCs. Possibilities to overcome this problem are complete sealing of glass-based cells, preparation of solid-state electrolytes or embedding a fluid electrolyte in a textile-based matrix. Here we report on a new route to avoid evaporation of the electrolyte. Using glycerin as the base for a iodine-triiodide electrolyte, glass-based DSSCs showed constant or even increasing efficiencies during more than three months, while the reference cells based on a commercially available water-based iodine-triiodide electrolyte showed decreasing efficiencies already after four weeks and were completely dried after two months. Our results suggest using glycerin-based fluid electrolyte, possibly in combination with a textile-based matrix, to create durable DSSCs without the necessity to perfectly seal them.
关键词： glycerin,iodine-triiodide,natural dye,electrolyte,textile fabric,dye-sensitized solar cells (DSSCs)
更新于2025-09-16 10:30:52
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Green synthesis of TiO2 nanoparticles using Bixa orellana seed extract and its application for solar cells
摘要： Mesoporous anatase TiO2 nanoparticles are the best photoanode materials for high performance DSSC. Chemical and physical methods used for the preparation of TiO2 nanoparticles suffer with environment related issues e.g. use of toxic solvents, hazardous by-products and consumptions of high energy. We have synthesized mesoporous anatase TiO2 nanoparticles from Titanium (IV) butoxide solution using Bixa orellana seed extract and further used it for making DSSC photoanode. The method offers environment friendly, cheaper and efficient DSSC. Structure, morphology, size and porosity of TiO2 nanoparticles were characterized using XRD, SEM, TEM and N2 sorption measurements. The amount of dye loading by TiO2 was obtained using desorption technique which revealed much higher dye loading for the plant seed grown nanoparticles (G-TNP). TNP and G-TNP demonstrated photovoltaic conversion efficiencies 1.03% and 2.97% respectively. This study therefore demonstrates that the synthesized mesoporous anatase TiO2 naoparticles can serve as promising photoanode materials for DSSC applications.
关键词： Natural dye,Thin film,Photoanode,TiO2 nanoparticles,Dye-sensitized solar cell,Bixa orellana
更新于2025-09-16 10:30:52
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Natural Dye of Musa acuminata bracts as Light Absorbing Sensitizer for Dye-Sensitized Solar Cell
摘要： Dye-Sensitized Solar Cell (DSSC) has attracted researcher attentions because of its ability in converting light and has good performance at relatively low costs. The highest conversion efficiency is 4%. Musa acuminata bracts extract and a spin coating method are used. DSSC is fabricated based on musa acuminata bracts extract in a variation of mass fraction 0.1–0.5 with an increase of 0.1. The absorbances of organic dyes are determined using Vis-Nir and the highest one is found at 0.3 mass fraction with a wavelength spectrum of 500-600 nm. Conversion efficiency is determined using the Nachriebe 101 tool.
关键词： natural dye,dye-sensitized solar cell,musa acuminata bracts,thin film,photosensitizer
更新于2025-09-16 10:30:52
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Photovoltaic properties of the flavonoida??based photosensitizers: Moleculara??scale perspective on the natural dye solar cells
摘要： The molecular modification and the effects of the gas and water media on the ability of some flavonoids as the photosensitizers in the natural dye-sensitized solar cells were theoretically investigated. According to the results, water increases the electrophilicity of the dyes and weakens the dye/TiO2 coupling, prohibiting the electron injection toward TiO2. A longer path for charge transfer and a less electron-hole overlap for dihydroxychromens elevate the electron transfer more efficient than trihydroxychromen-based flavonoids. However, the presence of water molecules within an increment in the OH groups in the flavonoid structures improves their spectroscopic properties, which is related to decrement in the gap of the frontier molecular orbitals and increment in the oscillator strength. Also, such favorable structural effects and influence of the water medium on the polarizability and excited-state lifetime have emerged. According to the energy conversion efficiency, water is a favorable solvent for dihydroxychromen-based flavonoids. Finally, different analyses on the structural geometries, excited-state, lifetime within the kinetics, and dynamics of the photovoltaic processes were performed and discussed.
关键词： natural dye,flavonoid,photovoltaic,absorption spectra,charge transfer
更新于2025-09-16 10:30:52
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Characterization of TiO2 photoanodes and natural dyes (Allamanda Blanchetti and Allamanda Cathartica) extract as sensitizers for dye-sensitized solar cell applications
摘要： In the present work, Dye-Sensitized Solar Cells (DSSC) were fabricated using fabricated TiO2 photoanodes and natural dyes (Allamanda Blanchetti (AB) and Allamanda Cathartica (AC)) as the sensitizers. Initially, TiO2 nanoparticles were synthesized by sol–gel technique and a thin ?lm of TiO2 was formed on the FTO substrate by Doctor Blade technique. Then, they were annealed at 400, 500, and 600 °C to act as the photoanode. X-ray diffraction analysis shows the prepared samples have tetragonal crystal structure with anatase and rutile phase. The average crystallite size was found to be 10–17 nm when the annealing temperature (TA) was increased from 400 to 600 °C. From UV–DRS analysis, the percentage of re?ectance was found to starts at 315 nm. The bandgap analysis shows the transitions were indirect allowed and the bandgap value decreases from 3.6 to 2.8 eV when the TA increases from 400 to 600 °C. From the optical absorption spectra, the absorption of dye and dye-sensitized TiO2 was found to be in the visible region. From PL analysis, the emission peak intensity of Ti4+ ?) vacancies with TA increases from 400 to 600 °C was noted. FESEM analysis shows the synthesized particles were spherical and from EDS the presence of Ti and O was con?rmed. From FTIR analysis, the functional groups presented in the prepared extracts were con?rmed. The Ef?ciency of DSSC was found to be 1.16 and 0.30% for AB sensitized TiO2 (400 °C) and AC sensitized TiO2 (400 °C) as photoanodes. From Electrochemical Impedance Spectroscopic (EIS) analysis, DSSC with AB + TiO2 shows low charge transfer resistance compared with AC + TiO2.
关键词： TiO2,Bandgap,Electrical measurements,XRD,Natural Dye,DSSC
更新于2025-09-12 10:27:22
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Dye-Sensitized Solar Cells Using Natural Dye as Light-Harvesting Material Extracted From the Leaves of Peltophoroum Pterocarpum
摘要： The Dye Sensitized Solar Cell (DSSC) was fabricated using the dye extracted from the leaves of Peltophorum pterocarpum. The dye was extracted using cold extraction with ethanol and water. The absorption nature of the extracted dye was analyzed using UV-Vis spectrometer. The structural property of the pure titanium dioxide (TiO2) nanoparticles was analyzed using powder X-ray diffraction (PXRD). The Surface morphology of the synthesized pure TiO2 nanoparticles was identified with high resolution scanning electron microscopy (HRSEM) analysis. The TiO2 films were coated on Fluorine doped Tin Oxide (FTO) using doctor blade method. The current - voltage character of the prepared DSSC are measured. From the J-V characteristic curves of cells, the parameters related to the solar cell performance were calculated. Natural dye is biodegradable and non-toxic having most of the extraction process harmless to environment. In addition, natural dye has the promising future as it is abundant.
关键词： Peltophorum pterocarpum,Natural dye,Titanium dioxide,HRSEM,DSSC
更新于2025-09-12 10:27:22
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The visible reflectance spectrum stability and water content resistivity of natural dye coating paint film consisting chlorophyll
摘要： The purpose of this paper is to study the colour stability and water content resistivity of the green colour coating paint film (consisting of chlorophyll) during exposure to ultraviolet A (UV-A). The natural green dye was prepared by immersing Cassia alata L. leaves in absolute ethanol. The extract was prepared in two batches of dye samples where one of it was a pure dye and the other was added with 3 Wt. % Cu(NO3)2 as an additive. Polymer blend as a binder was prepared by mixing poly(methyl methacrylate) (PMMA) and commercial acrylic polyol. The blended polymer was mixed with the natural dye in a specific ratio and applied as coating paint film on glass panel surfaces. The visible spectrum stability (colour stability) and water content resistivity of the coating paint films during exposure to UV-A were monitored. Addition of Cu(NO3)2 had improved the colour stability of the coating paint film. Fourier transform infrared spectroscopy analysis showed that both coating paint films do not absorb water and are resistive to water content. The ability of Cu(NO3)2 as an colour stability additive to the natural green dye applied in the coating paint film. The coating paint film developed in this work is suitable to be applied on glass substrates. The colour stability of the coating paint film was analysed by using the reflectance spectrum.
关键词： Chlorophyll,Colour stability,Natural dye,Paints,Organic coatings
更新于2025-09-11 14:15:04