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Dye sensitized solar cells based on titanium dioxide nanoparticles synthesized by flame spray pyrolysis and hydrothermal sol-gel methods: a comparative study on photovoltaic performances
摘要： Synthesis methods, shape and size of the nanocrystalline titanium dioxide (TiO2) are very crucial parameters for the power conversion efficiency of dye sensitized solar cells. In this article, nanoparticles of TiO2 powders have been synthesized via flame spray pyrolysis and hydrothermal sol-gel methods. These powders have been characterized by X-ray diffraction and scanning electron microscopy. In particular, the photovoltaic performances of the dye sensitized solar cells based on TiO2 synthesized by flame spray pyrolysis and hydrothermal sol-gel method have been compared. A commercial dye, N719 and a platinum doped counter electrode have been used for fabricating cells. Furthermore, a standard dye sensitized solar cell device has been fabricated by using a commercial Titania electrode in order to use as a reference cell. As a result, power conversion efficiencies of solar cells (under standard conditions, AM 1.5 G, 100 mW cm?2) have been calculated as 2.44, 3.94, and 7.67 % with TiO2 synthesized via flame spray pyrolysis method, hydrothermal sol-gel method and reference Titania electrode, respectively.
关键词： Sol gel,Flame spray pyrolysis,Dye sensitized solar cells,Hydrothermal method
更新于2025-09-12 10:27:22
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Sol–gel approach for the growth of vertically aligned 3D-TiO2 nanorod arrays as an efficient photoanode for high-performance dye-sensitized solar cells
摘要： In this study, a facile, low cost, and scalable sol–gel method has been proposed for the coating of ultra-thin layer of TiO2 on FTO substrate as a seed layer for the growth of 3D-TiO2 nanorod (3D-TiO2-NR) arrays on FTO. Then, the two-step hydrothermal process including nanorod growth and the chemical etching treatment was proceeded for the fabrication of FTO/3D-TiO2-NR photoanodes. The thickness of the deposited TiO2 in FTO/TiO2-sg samples was measured with small-angle X-ray scattering technique, and it was obtained to be 21.3 nm. FE-SEM and TEM techniques were used for the morphological characterization of 3D-TiO2-NR, and it was obtained that the tightly adhered film of vertically aligned 3D-TiO2-NR with two-layer nanostructuring is formed with a cubic base and a nanorods head. Finally, DSSCs with iodine-based and cobalt(II/III) tris(2,2′-bipyridine) complex-based electrolytes with two different photoanodes including 3D-TiO2-NR and TiO2-NP were assembled and their photovoltaic characteristics were investigated. For [Co(bpy)3]2+/3+ shuttle-based DSSC, the obtained power conversion efficiency (η) was about 3.5% with Jsc of 9.36 mA cm?2 in 3D-TiO2-NR-based DSSC, while η of TiO2-NP-based DSSC was about 1.4%. The results showed that employing 3D-TiO2-NR-based photoanode in DSSCs with bulky electron shuttles remarkably improves the photovoltaic characteristics of DSSCs. Electrochemical impedance spectroscopic studies also showed the lower charge transfer resistances for DSSCs with nanorod-based photoanode building blocks.
关键词： Adhesion,Electron shuttle,TiO2 nanorod arrays,DSSC,Cobalt(II/III) tris(2,2′-bipyridine) complexes,Sol–gel
更新于2025-09-12 10:27:22
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Sol–gel ZnO modified by organic dye molecules for efficient inverted polymer solar cells
摘要： ZnO layer was modified with the addition of Cationic dyes including Crystal Violet (CV)/Ethyl violet (EV) in sol–gel process for an electron transport layer in inverted polymer solar cells (PSCs). X-ray photoelectron spectra showed the presence of CV/EV at the top of ZnO surface. Besides, oxygen defect was significantly reduced by CV/EV modification due to the chloride occupation. Furthermore, the amount of CV/EV decreased progressively from ZnO surface to bottom, being evidenced by depth profile. With modification, the ZnO surface became smoother and more hydrophobic to improve the contact with active layer. Meanwhile, CV/EV participated in the crystallization which resulted in the larger ZnO crystal grain size. Interface dipole after modification would slightly reduce the work function of ZnO and the energy barrier between ZnO and active layer via Ultraviolet Photoelectron Spectroscopy and External Quantum Efficiency analysis. Accordingly, inverted PSCs possessed better morphology, better electron extraction ability with ZnO modified by CV and EV respectively, rendering the power conversion efficiency up to 8.80% and 9.06% in comparison to the pristine ZnO (7.59%). In conclusion, we demonstrate a facile way to improve morphological and electrical properties of ZnO layer by simply adding CV/EV in sol–gel ZnO to fabricate high performance PSCs.
关键词： Interfacial modification,Cationic dye,Polymer solar cells,Electron transport,Sol–gel ZnO
更新于2025-09-12 10:27:22
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SILAR Controlled CdS Nanoparticles Sensitized CdO Diode Based Photodetectors
摘要： In this research, we have produced Al/CdS nanoparticles-CdO/p-si/Al photodetetor and investigated its optical and electrical characteristics for various optoelectronic applications. The CdO thin film was covered by using sol-gel spin coating method onto the silicon, followed by CdS nanoparticles constitution by the help of SILAR technique. In order to examine the morphological and optical characteristics of fabricated photodetector, the field emission scanning electron microscopy and UV-Vis spectroscopy were utilized, and the band gap of the prepared film was determined as 2,17 eV with the help of these analyzes. The current behavior against the varying voltage values were investigated for the different intensities of solar light conditions and the significant diode parameters were computed by the use of this measurements. As a result of this computation, the barrier height value was found to be 0.49 eV while the ideality factor value was 3.2, and the photoresponse of the photodetector was measured as approximatelly 2.65 × 103. Besides, the transient photocurrent and photocapacitance charactersitics were examined for distinct light conditions. Finally, the interface states were calculated from the capacitance/conductance–voltage (C/G–V) measurements.
关键词： Optical characteristics,SILAR method,Sol-gel method,CdO thin film,Electrical characteristics,CdS nanoparticles
更新于2025-09-12 10:27:22
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Ultraviolet photodetectors based on doped ZnO films
摘要： In this paper, we report the realization of ultraviolet (UV) photodetector based on doped ZnO films. The ZnO p-n junction was fabricated on indium tin oxide (ITO) coated glass, which consists of n-type and p-type layers based on Ga-doped (2 at.%) and N-doped (20 at.%) ZnO films, respectively. The current-voltage (IV) characteristics, photosensitivity, photoresponsitivity, and photocurrent gain were derived to determine the performance of the device. At 5 V reverse bias, the ZnO-based UV photodetector exhibits photosensitivity of 10.9, photoresponsivity of 2.1 × 10-2 AW-1, and photoconductive gain of 7.2 × 10-2.
关键词： ultraviolet photodetectors,sol-gel spin coating,p-n junction,doped ZnO films
更新于2025-09-12 10:27:22
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Transforming polymorphs of Co-doped TiO2 nanoparticles: an efficient photo-electrode for dye-sensitized solar cells
摘要： Simple sol–gel assisted spin coating technique was used to prepare cobalt-doped TiO2 films for the application of dye-sensitized solar cells (DSSC). TiO2 photo-electrodes with few Co concentrations (0, 0.025, 0.05, 0.075 and 0.1 M) were prepared on conducting glass substrates. The morphology, structure and composition of the Co:TiO2 films were observed using SEM, XRD and EDAX analysis. The average crystallite size of Co:TiO2 nanoparticles obtained from diffractograms are in the range of 3–12 nm. The transformation of polymorphs from anatase to rutile and vice versa for the increasing concentrations of Co in TiO2 films is observed. The values of optical bandgap energy for Co-doped films are observed to be higher than the pure TiO2 film and the highest is for the dopant level of 0.025 M. Doping of 0.1 M Co in TiO2 enhances the power conversion efficiency of DSSC by 65% compared to pure TiO2 film, demonstrating the influence of Co doping on the functioning of DSSC.
关键词： TiO2,Co-doped TiO2,Sol–gel,DSSC,Spin coating technique
更新于2025-09-12 10:27:22
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Development of a Hybrid Chitosan- and Niacinamide-Coupled ZnO Nanoparticle Composite for Sun Protection Application
摘要： Zinc oxide nanoparticles (ZnO) have long been utilized as UV-protective sunscreen components due to their high durability and lower skin irritation while maintaining capability for blocking UV rays. However, the dispersal and transparency properties of ZnO need to be enhanced in order to improve the capacity for creating effective sunscreen through control of the physiochemical properties of ZnO. In this study, chitosan or niacinamide, which are suitable functional cosmetic compounds and effective skin lightening agents, are combined with ZnO for the development of better UV-protective products. Each biocompatible coating material is individually attached on its surface after the synthesis of ZnO. The size is 70 nm using the sol-gel method. Their morphology and chemical structure are characterized by FT-IR, XRD, SEM, TEM, TGA, and zeta potential. The results indicate that approximately 50% of chitosan and 5% niacinamide were coated on the ZnO. To confirm the capacity of each surface-coated ZnO with chitosan and niacinamide as a sunscreen, we measured their transmission, reflectance, and sun protection factor (SPF) using a UV spectrophotometer and SPF. As a result, the niacinamide-coated ZnO shows remarkably lower transmission and high reflectance against UV rays than that of bare ZnO and chitosan-coated ZnO. Furthermore, niacinamide-coated ZnO exhibits great lightening effects. Consequently, these results demonstrate that niacinamide coating is highly effective for the production of sunscreen emulsions.
关键词： Zinc oxide nanoparticles,TEM,FT-IR,SEM,XRD,UV-protective sunscreen,TGA,chitosan,SPF,sol-gel method,zeta potential,niacinamide,sun protection factor
更新于2025-09-12 10:27:22
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Preparation of novel lead-free Ag-doped glass frit for polycrystalline silicon solar cells by sol-gel method
摘要： A novel Ag-doped glass frit is prepared by the sol-gel method. Nitrogen adsorption-desorption isotherms indicate that the frit has a large BET surface area and a small particle size which promotes front contact metallization. When the glass frit is used for the front contact electrode of polycrystalline silicon solar cells (pc-Si solar cells), it exhibits excellent wettability and etching results on the SiNx layer and the Si substrate. The pc-Si solar cells with the as-prepared frit has a better photoelectric conversion efficiency (18.2%) and is 0.8% higher than the solar cells using the conventional frit, which is due to the frit will produce a lot of Ag nanocrystals at the interface of the glass layer, promoting the formation of excellent ohmic contact between the Ag electrode and n-Si layer, and reducing the contact resistance of solar cells.
关键词： Ag-doped glass frit,polycrystalline silicon solar cells,photoelectric conversion efficiency,sol-gel method
更新于2025-09-12 10:27:22
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Photo-Patternable Quantum Dots/Siloxane Composite with Long-Term Stability for Quantum Dot Color-Filters
摘要： Incorporation of quantum dots (QDs) into color-filters (CFs) are desired for less energy loss and wider viewing angle compared to conventional display. However, aggregation and vulnerability to heat, moisture, and chemicals in photo-patternable matrix are critical issues of the QD-CFs with high QDs concentration. Herein, we fabricated red (10 wt%) and green (20 wt%) QD-CFs using photolithography of QD/siloxane ink containing secondary thiol monomer. Ligand exchanged QDs were chemically incorporated in methacrylate oligo-siloxane resin. QD/siloxane composite showed superior stability under harsh heat and moisture (85 ℃/5% RH and 85 ℃/85% RH) conditions and chemicals (EtOH, HCl and NaOH) compared to conventional QD/PR (commercial negative photoresist). 10 μm-thick QD-CFs effectively converted blue light emitted from LED chip into red and green light, and the obtained white PL through QD-CF showed wide color gamut which was 108% relative to NTSC. From these advantages, QD/siloxane composite will be beneficial as color-conversion photoresist to be used as color-filters in LCDs, μLEDs, and OLEDs.
关键词： Sol-gel condensation,Siloxane hybrids,Photo-patternability,Quantum dot color-filter,Thermal and chemical stability
更新于2025-09-12 10:27:22
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The role of cation and anion dopant incorporated into a ZnO electron transporting layer for polymer bulk heterojunction solar cells
摘要： Doping is a widely-implemented strategy for enhancing the inherent electronic properties of charge transport layers in photovoltaic devices. A facile solution-processed zinc oxide (ZnO) and various cation and anion-doped ZnO layers were synthesized via the sol–gel method and employed as electron transport layers (ETLs) for inverted polymer solar cells (PSCs). The results indicated that all PSCs with doped ZnO ETLs exhibited better photovoltaic performance compared with the PSCs with a pristine ZnO ETL. By exploring the role of various anion and cation dopants (three compounds with the same Al3+ cation: Al(acac)3, Al(NO3)3, AlCl3 and three compounds with the same Cl? anion: NH4Cl, MgCl2, AlCl3), we found that the work function changed to favor electronic extraction only when the Cl anion was involved. In addition, the conductivity of ZnO was enhanced more with the Al3+ cation. Therefore, in inverted solar cells, doping with Al3+ and Cl? delivered the best power conversion efficiency (PCE). The maximum PCE of 10.38% was achieved from the device with ZnO doped with Al+ and Cl?.
关键词： electron transport layers,Al3+ cation,polymer solar cells,doping,Cl? anion,photovoltaic performance,power conversion efficiency,sol–gel method,zinc oxide
更新于2025-09-12 10:27:22