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High Efficiency Dye Sensitized Solar Cell from <i>Tectona Grandis</i> and red <i>Crysanthemum Morifolium</i> as a Sensitizer
摘要： Tectona Grandis leaves and red Crysanthemum Morifolium have been used as sensitizers for dye sensitized solar cell (DSSC) using organic solvents by ethanol, citric acid, and distilled water in respectively with the ratio of 5 : 1 : 4. TiO2 paste was spin-coated on top Indium Tin Oxide (ITO) conductive glass and calcinated at temperature of 450oC for 10 min. The chemical properties were analysis by using Fourier transform infrared spectroscopy (FTIR) indicated the presence of anthocyanin from Tectona Grandis leaves and red Crysanthemum Morifolium petal. The physical properties were analysis by using UV-Vis spectrophotometer was performed to measure the absorbance of dye solution in the visible spectrum range and X-Ray Diffractometer (XRD) was used to determine the structure of TiO2/ITO and Dye/TiO2/ITO. Among the three dyes studied, the mixed dye solution from Tectona Grandis leaves and red Crysanthemum Morifolium was shows the best photosensitization effects with the conversion efficiency is 0.834 %.
关键词： sensitizer,red Crysanthemum Morifolium,Tectona Grandis,Dye Sensitized Solar Cell,anthocyanin
更新于2025-09-19 17:13:59
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A novel σ-linkage to dianchor dyes for efficient dyes sensitized solar cells: 3-methyl-1,1-cyclohexane
摘要： We have synthesized two sensitizers based on the 3-methyl-1,1-cyclohexane, a novel σ-linkage to prepare dianchored dyes. These novel dyes are difunctionalized systems with aniline-donor (D), a π-conjugated spacer (π) based on thiophene or bithiophene and cyanoacetic acid as acceptor and anchoring group (A). The UV–vis absorption and the Differential Pulse Voltammetry have been used to study the effect of both σ-linkage and π-spacer. The relevant increase of the molar extinction coefficient of these dianchored dyes has been investigated by theoretical calculations. The dye bearing bithiophene results in a both broader and higher absorption as well as an adequate efficiency to transfer charge from D to A with respect to bithiophene dyes. The photovoltaic properties of these sensitizers without co-adsorbent have been studied. The novel difunctionalized derivatives present a relevant increase of the photocurrent density which results in a better performance with respect to the single dyes. The difunctionalized derivative based on bithiophene has given rise to an efficiency value of 7.8% and is stable up to 1000 h after the device assembly.
关键词： Aggregation,Metal-free sensitizer,Temporal stability,Multichromophore,Dye
更新于2025-09-16 10:30:52
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Rational design of SM315-based porphyrin sensitizers for highly efficient dye-sensitized solar cells: A theoretical study
摘要： To explore high-efficiency dye-sensitized solar cells (DSSCs), five D-π-A type porphyrin dyes derived from SM315 synthesized by Gr?tzel et al with electron-rich units D1-D5 as donors were investigated using density functional theory (DFT) and time-dependent density functional theory (TD-DFT). The enhanced light harvesting abilities of all designed dyes are reflected by widened light harvesting efficiency curves, extended absorption spectra to near-infrared region and ~84 nm red-shifted maximum absorption wavelengths as well as double increased oscillator strengths. Mainly contributed by the remarkable increment of predicted short-circuit current density, the predicted overall efficiency of the design dyes increases by ~27% compared to SM315. Especially, S101 could be the most promising candidate with the highest predicted overall efficiency of 16.7% among all of dyes. The dynamic simulations of interfacial electron transfer of all the investigated dyes expound that the excited electrons inject almost totally into semiconductor TiO2 within 200 fs. This work would provide guidance for exploring potential sensitizers in highly efficient DSSCs.
关键词： porphyrin sensitizer,interfacial electron transfer,power-conversion efficiency,dye-sensitized solar cell
更新于2025-09-12 10:27:22
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Stilbene Based Organic Dye as Efficient Sensitizer for NLO and Dye-Sensitized Solar Cells: A First Principle Study
摘要： In this study, we have designed five different Stilbene based dyes as efficient sensitizers for Nonlinear Optical Properties (NLO) and Dye-Sensitized Solar Cells (DSSCs). Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) have used to investigate molecular properties, in order to influence and performance of the dye sensitizer in the DSSCs. The theoretical result indicates that the HOMO and LUMO energy levels of this dye can be ensured a positive effect on the process of photoelectron injection into semiconductor surface and dye regeneration by the electrolyte. The solar energy conversion efficiency, effective key parameters in influence with the Short-Circuit Current Density (JSC), Light Harvesting Efficiency (LHE) and Electron injection driving force (?Ginject) were discussed. The Stilbene-based dyes can be used as a potential sensitizer for photoelectron injection into the semiconductor surface due to its best electronic structure and optical properties of the good photovoltaic parameters.
关键词： Reorganization energy,Light Harvesting Efficiency,Driving force,Short-Circuit Current Density,Dye sensitizer
更新于2025-09-12 10:27:22
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Performance enhancement of small molecular solar cells via luminescent sensitizer 4,5-bis(carbazol-9-yl)-1,2- dicyanobenzene (2CzPN)
摘要： Enhanced performance of small molecule organic solar cells (SM-OSCs) is presented by incorporating a blue luminescent sensitizer layer 4,5-bis(carbazol-9-yl)-1,2-dicyanobenzene (2CzPN). The VOC increases from 0.98 V to 1.17 V due to the slightly deeper highest occupied molecular orbital (HOMO) level of 2CzPN than subphthalocyanine (SubPc). The estimated hole injection barrier slightly increases from 0.809 eV (without 2CzPN) to 0.874 eV (5 nm 2CzPN) and the hole mobility simultaneously decreases. This strategy provides a facile approach for effective utilization of high-energy photons.
关键词： SubPc,2CzPN,small molecule solar cells,luminescent sensitizer
更新于2025-09-11 14:15:04
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Monte Carlo simulation of a transversely excited solar-pumped fiber laser
摘要： A Monte Carlo ray-tracing simulation was developed for a transversely excited solar-pumped fiber laser without focusing optics. To make this possible, the fiber is immersed in a liquid sensitizer and sandwiched between highly reflective mirrors. The top reflector is dichroic to transmit solar radiation but reflect fluorescence to confine photons that match the absorption band of the active fiber. Simulation was used to evaluate the validity of the concept and optimize device performance. For comparison with the calculations, preliminary experiments were conducted by illuminating a 30 cm aperture, laser module with a solar simulator. The observed gains were in good agreement with the calculations for various conditions, such as sensitizer concentration and mirror reflectivity. Finally, we show that the predicted output power reaches 29 mW when the fiber length is optimized, and it will be enhanced to 150 mW with 0.21% solar-to-laser efficiency under the assumption of a reabsorption-free sensitizer.
关键词： unconcentrated,dichroic mirror,Monte Carlo simulation,sensitizer,solar-pumped fiber laser,transversely excited
更新于2025-09-11 14:15:04
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Fabrication of Optimized Eco-friendly Dye-Sensitized Solar Cells by Extracting Pigments from Low-Cost Native Wild Plants
摘要： The major proportion of dye-sensitized solar cells (DSSCs) fabrication cost is attributed to the pigments. In this study, to increase the performance/cost ratio of DSSCs, we used several wild regional plants of Persian Gulf zone for natural pigment production. At first, the optimum conditions for pigment extraction were obtained for all plants using response surface methodology. The results showed that increasing temperature, as well as extraction time, increased the pigment extraction efficiency while the pH of the solution did not exert a significant effect on the extraction process. Besides, the microwave-assisted method and pure ethanol have the highest extraction efficiency compared to ordinary solvent extraction and water as the extraction method and solvent, respectively. Moreover, all pigments were characterized using circular dichroism, dynamic light scattering, and zeta potential techniques. The results showed that the extracted pigments from Malva verticillata have the highest optical activity while all kinds of pigments tend to make aggregates 12 h after the extraction. Finally, the effectiveness of each pigment was evaluated as a sensitizer in natural DSSCs that fabricated using the doctor blade technique. Based on the photovoltaic results of the DSSCs sensitized with extracted pigments, the open circuit voltage and short circuit current ranged from 0.35 to 0.542 ??and 0.802 to 1.702 ????, respectively. The Microwave-assisted Malva verticillata-DSSC owned the highest energy conversion efficiency of 1.702% as well as the comparable open circuit voltage to that of the reference DSSC that made using synthetic sensitizer. This superiority could be attributed to the highest pigments concentration as well as the highest pigments optical activity of Malva verticillata. Moreover, the results showed that the LUMO energy level and the band gap of the extracted pigments from Malva verticillata are better than the other natural pigments for DSSC fabrication. Besides, due to the presence of carbonyl and hydroxyl groups in chemical structures of extracted pigment from Malva verticillata, an effective bond between the pigment and TiO2 surface might be achieved and thereby increasing the energy conversion efficiency.
关键词： solar cell,sensitizer,natural,Algae,pigment,Malva verticillata
更新于2025-09-11 14:15:04
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Elucidating the mode of action for thiophene-based organic D-π-A sensitizers for use in photodynamic therapy
摘要： Photodynamic therapy (PDT) is a non-invasive, selective, and cost-effective cancer therapy. The development of readily accessible templates that allow rapid structural modification for further improvement of PDT remains important. We previously reported thiophene-based organic D-π-A sensitizers consisted of an electron-donating (D) moiety, a π-conjugated bridge (π) moiety, and an electron-accepting (A) moiety as valuable templates for a photosensitizer that can be used in PDT. Our preliminary structure-activity relationship study revealed that the structure of the A moiety significantly influences its phototoxicity. In this study, we evaluated the photoabsorptive, cellular uptake, and photo-oxidizing abilities of D-π-A sensitizers that contained different A moieties. The level of phototoxicity of the D-π-A sensitizers was rationalized by considering those three abilities. In addition, we observed the ability of amphiphilic sensitizers containing either a carboxylic acid or an amide in an A moiety to form aggregates that penetrate cells mainly via endocytosis.
关键词： Organic dye,Photodynamic therapy,Sensitizer,Singlet oxygen,Endocytosis
更新于2025-09-09 09:28:46
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A Facile Strategy for Preparation and Application of Squaraine Nanometer Hybrids with Broad Band Absorption
摘要： Organic materials are receiving more attention in the solar cell due to their better solution process, controllable synthesis, tunable chemical and physical properties. However, the focus problem of compatibility and aggregation is to be solved urgently in organic materials, which inevitably limits them widely application. To this end, an inorganic-organic hybrid materials with wide-band absorption is designed and prepared, that incorporates octavinyl-polyhedral oligomeric silsesquioxane with 6-bromoquanaldine to produce H1, then reacts with squaric acid to design H2, which efficiently avoids the fluorescence quenching due to the steric hindrance. The electrochemical results shows that the energy level of H2 is match well with the commercial dye N719. Hence it shows a better photovoltaic performance based on dye-sensitized solar cell, along with power conversion efficiency up to 7.73 % when it is co-sensitized with N719. The hybrid system exhibits good performances in solar cell and long-term stability.
关键词： dye-sensitized solar cell,disaggregation,broad-band absorption,co-sensitizer
更新于2025-09-09 09:28:46
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The Possible Limitation of the Intra-Operative PDT Dosimetry: On Wounds Healing, Following Tumor Resection
摘要： In the past three decades, laser research in Saudi Arabia had provided methodical findings for the advancement of laser application in medicine. At low power emission, lasers incite photochemical effects, which diverge into two inevitable therapeutic phenomena Photo Dynamic Therapy (PDT) and Low Power Laser Therapy (LPLT). The term PDT refers to the combined use of a Photo Sensitizer (PS) (Dye) plus Laser to treat and diagnose malignant cells. In the doses usually used for treatments, the dye alone or the laser alone has no effect. PDT, a laser treatment for cancer, involves light and PS, (i.e. a light-sensitive drug, for instance – Hemato Porphyrin Derivative (HPD), Photofrin, and 5-Aminolevulinic Acid etc.) for the selective destruction of Neoplastic cells. Rigorous PDT studies in our laboratory are ongoing since 1985 aiming to determine the most suitable laser wavelength and PS, in thyroid tumor using nude mice as animal models. Previously we have established the Clonogenic Survival Rates, and tumor growths following PDT as a function of tumor volume for RIF-1 (murine fibro sarcoma) in C3H mice. We were able to completely eradicate small tumors (i.e. tumor volume < 50 mm3), and decrease the growth rates of larger tumors by executing superficial PDT followed by interstitial PDT. Thus, unlike ionizing radiation, PDT may be repeated if necessary without yielding cumulative toxicity [1-4]. The high laser doses required for the presents widely used dye {Photofrin @ I and II (HPD)}, may result, as our recent experiments show, in inhibiting Wound Healing of up to 8%. Where if the PDT laser dose decreased it could stimulate acceleration of wound healing up to 30%.Where the Incident dose for PDT with Photofrin of 80 J/cm2 give zero bio activation for wound healing. With regard to LPLT, we study its effects on wounds and burns in Sprague-Dawley rats. We noticed healing acceleration, zero-bio activation, and inhibition that depended on the wavelength, dose and treatment schedule, but not on dose rate and laser-skin transmission. We further observed that LPLT had higher wound healing acceleration than Light Emitting Diode (LED), or pharmaceutical treatments. We found 29% healing acceleration with HeNe (632.8 nm) laser at 5 J/cm2 (human dose) 40 J/cm2 (animal dose), applied three times a week. 42% of the animals had better cosmos’s .When wound healing was impaired by diabetes, LPLT accelerated healing by +8.6% relative to diabetic controls (-42%) [5-8]. This support the suggestion of using other dyes (new PS, developed to overcome some of other problems, like unacceptable prolongation of the procedure if large area treated and poor absorption of light By HPD). Since then several classes of PS were developed. The main classes are: porphyrin derivatives, Chlorins, Phthalocyanines and Porphycenes etc., Must have the properties of high absorption of laser, and deep tissue penetrations. Also these dyes should use a simulative laser dose for the wound healing, as the PDT optimum dose when combined with surgery, beside its efficacy for selectively destroying malignant tissue. The laser incident dose For PDT suggested from our experiments is up to 40 J/cm2 to give also wound healing acceleration in the animal, (which should converted to human),and up to 140 J/cm2 for deceleration in the animal. We advocate the Intraoperative Photo Dynamic Therapy (IPDT). Initially, surgical lasers excise/ablate visible tumors sealing the lymph vessels in the process thereby preventing further metastasis. Highly selective PDT follows removing microscopic residual cancer cells that remain after the surgery. Finally, LPLT is applied to accelerate healing of postoperative normal wounds (and /or Diabetic wounds). In time, medical lasers shall supersede some conventional therapies simply because of being overwhelmingly effective in various clinical applications.
关键词： Stimulation,HPD,Photo-bio modulation,Photo dynamic therapy,Low power laser therapy,Tumors,Photo sensitizer,Inhibition,Wound healing
更新于2025-09-04 15:30:14