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Spiro[fluorene-9,9a?2-phenanthren]-10a?2-one as auxiliary acceptor of D-A-??-A dyes for dye-sensitized solar cells under one sun and indoor light
摘要： Six novel organic dyes (RY1~RY6) containing spiro[fluorene-9,9'-phenanthren]-10'-one as an auxiliary acceptor were synthesised and effectively used for the fabrication of D-A-π-A type dye-sensitized solar cells (DSSCs). The molecular structures were modified by introducing a novel spiro[fluorene-9,9'-phenanthren]-10'-one auxiliary acceptor group between the donor and the π-bridge. The molecular rigidity can be enhanced by depressing intermolecular aggregation and carbonyl group can trapping the Li+ ions to retard the charge recombination. The sensitizer RY3 was found to perform remarkable light-harvesting efficiency of 6.30% at AM1.5 solar condition and 21.67% at TL84 (2500 lux) illuminations without DCA co-deposition. For further improvement, a higher efficiency can be achieved through a suitable co-sensitization of N719 and RY3, which displayed an efficiency of 8.55% under one sun (AM 1.5). While operated under indoor light, the efficiency was boosted to 25.57% and 27.04% at 1000 & 2500 lux illuminations, respectively. The high performance of co-sensitization of N719 and RY3 can be ascribed to a high surface coverage and a broader range of absorption wavelength. Stability test of the device co-sensitized with N719 and RY3 showed a mild decay of PCE 3.74% after 96 h, while it retained 84.49% of its original PCE after 336 h in ambient atmosphere without encapsulation.
关键词： Spiro[fluorene-9,9'-phenanthren]-10'-one,Co-sensitization,High performance under indoor light,Dyes sensitized solar cells
更新于2025-09-19 17:13:59
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Dye-sensitized solar cells using fluorone-based ionic liquids with improved cell efficiency
摘要： Dye-sensitized solar cells using fluorone-based ionic liquids with improved cell efficiency. Six trihexyltetradecylphosphonium chloride (P6,6,6,14Cl) based ionic liquids (IL) with dianionic fluorone derivatives were synthesized with total exchange of chloride from the dianionic dye: Fluorescein (a), Rose Bengal (b), Phloxine B (c), Eosin B (d), Eosin Y (e) and Erythrosin B (f). Spectroscopic characterization of these viscous salts indicated the presence of the expected 1 or 2 strong absorption bands. A total of 12 compounds, as sodium (from a to f) or as trihexyltetradecylphosphonium dianion salts (from a0 to f0), were used for sensitization of nanocrystalline TiO2. Here, we report the sensitization activity of these metal free dyes in terms of current–potential curve, open-circuit potential, fill factor, and overall solar energy conversion efficiency which have been evaluated under 100 mW cm?2 light intensity. We developed a strategy to improve the light harvesting of these conventional dyes by simple cationic exchange which was accompanied by a minimum of 30% increase in the cell photovoltaic conversion efficiency. Also, for Eosin B the binding to TiO2 apparently allows reduction of the –NO2 electron-withdrawing group to –NO2?. This provides a new interaction between the reduced nitro group and the TiO2 surface, reflecting an improvement in the overall DSSC performance reaching its maximum of 0.65% efficiency after light DSSC soaking. Factors that improve DSSC performance like aggregate inhibition, increment of the electrode's quasi-Fermi level and slight red shift in the absorption spectra of the tested anionic dyes were achieved by simple cationic exchange.
关键词： TiO2 sensitization,Cationic exchange,Photovoltaic conversion efficiency,Fluorone-based ionic liquids,Dye-sensitized solar cells
更新于2025-09-16 10:30:52
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Near-infrared Laser Triggered Full-Color Tuning Photon Upconversion and Intense White Emission in Single Gd2O3 Microparticle
摘要： Full-color emission fluorescence materials are of imperious demands in information storage, graphics imaging and anti-counterfeiting fields. However, it is still a formidable challenge to develop a single material with full-color emission and high purity white output under a NIR-light excitation. Herein, we design a novel and convenient strategy to tune the upconversion luminescence color with full color range in lanthanide ions doped Gd2O3 microspheres via a single NIR laser sensitization. Different from the typical ion-dependent tuning of color, the bright and flexible full-color emission tuning from blue to cyan, green, yellow, pink, and red can be controllable implementation in a single microparticle. Particularity, benefiting from the laser sensitive color adjustment, highly intense white color emission can be simultaneously achieved in diverse doped ion concentration particles. In addition, the upconversion emission intensity has been evidently improved if using a NIR laser sensitization, leading to significantly enhanced upconversion red luminescence signal (44-fold) at the power 446 mW. The mechanistic investigations and dynamics analysis reveal that the unprecedented color tunability from these microcrystals is attributed to dynamic control of multi-energy transfer and multi-cross relaxation process. Furthermore, owning to their excellent upconversion luminescence properties, Gd2O3 microparticles could be used to the anticounterfeiting application in different colors. These findings not only open a way to fabricate a single material to fine tuning upconversion emission in a full color gamut, but also give the possibility to construction of the multicolor imaging for anti-counterfeiting applications.
关键词： upconversion luminescence,anti-counterfeiting,full color emission,lanthanide ions doped Gd2O3 microspheres,white color emission,laser sensitization
更新于2025-09-16 10:30:52
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Performance Enhancement of Betanin Solar Cells Co-Sensitized with Indigo and Lawsone: A Comparative Study
摘要： Co-sensitization is an important strategy toward e?ciency enhancement of solar cells by enabling better light harvesting across the solar spectrum. Betanin is a natural dye which absorbs light in the major portion of the incident solar spectrum (green region) and is the most e?cient natural pigment used in dye-sensitized solar cells. This study investigates the performance enhancement of a betanin solar cell by co-sensitizing it with two natural pigments which show complementary light absorption, indigo and lawsone, absorbing in the red and blue regions of the solar spectrum, respectively. The calculated highest occupied molecular orbital and lowest unoccupied molecular orbital energies of the pigment molecules, derived from density functional theory (DFT) simulations, con?rmed their optimal alignment with respect to the conduction band energy of the TiO2 semiconductor and reduction potential energy level of the I?/I3 ? electrolyte, a necessary requirement for optimal device performance. Lawsone solar cells displayed better performance, showing average e?ciencies of 0.311 ± 0.034%, compared to indigo solar cells showing e?ciencies of 0.060 ± 0.004%. Betanin was co-sensitized with indigo and lawsone, and the performances of the co-sensitized solar cells were compared. The betanin/lawsone co-sensitized solar cell showed a higher average e?ciency of 0.793 ± 0.021% compared to 0.655 ± 0.019% obtained for the betanin/indigo co-sensitized solar cell. An 11.7% enhancement in e?ciency (with respect to betanin) was observed for the betanin/indigo solar cell, whereas a higher enhancement of 25.5% was observed for the betanin/lawsone solar cell. Electrochemical impedance spectroscopy studies con?rmed that the higher e?ciency can be attributed to the higher electron lifetime of 313.8 ms in the betanin/lawsone co-sensitized solar cell compared to 291.4 ms in the betanin/indigo solar cell. This is due to the energy levels being more optimally aligned in lawsone compared to that of indigo, as observed in the DFT studies, and the lack of dipole moment in indigo, resulting in more e?cient charge separation and charge transfer in lawsone.
关键词： DFT simulations,indigo,electrochemical impedance spectroscopy,dye-sensitized solar cells,co-sensitization,betanin,lawsone
更新于2025-09-12 10:27:22
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High performance solid state solar cells incorporating CdS quantum dots and CH3NH3PbI3 perovskite
摘要： Since 2012, halide perovskites CH3NH3PbX3 (X = Cl, Br, or I) have been the topic of intensive research due to their excellent structural, optical and electronic properties and their application to perovskite solar cells (PSCs). PSCs are a new type of third-generation photovoltaics presenting low cost, ease of construction and power conversion efficiencies (PCEs) exceeding 23%, challenging the Si-based devices. This work describes a novel solution processed PSC structure: FTO/TiO2(CL)/mp-TiO2/CdS/Perovskite/Spiro-MeOTAD/Ag, using co-sensitization of quantum dots (QDs) with perovskite materials. This new cell architecture improves the device performance and characteristics and gives us the opportunity to develop solid state QDs cells.
关键词： quantum dot solar cells,CdS,co-sensitization,perovskite solar cells
更新于2025-09-12 10:27:22
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Electrophoretic Deposition of Quantum Dots and Characterisation of Composites
摘要： Electrophoretic deposition (EPD) is an emerging technique in nanomaterial-based device fabrication. Here, we report an in-depth study of this approach as a means to deposit colloidal quantum dots (CQDs), in a range of solvents. For the first time, we report the significant improvement of EPD performance via the use of dichloromethane (DCM) for deposition of CQDs, producing a corresponding CQD-TiO2 composite with a near 10-fold increase in quantum dot loading relative to more commonly used solvents such as chloroform or toluene. We propose this effect is due to the higher dielectric constant of the solvent relative to more commonly used and therefore the stronger effect of EPD in this medium, though there remains the possibility that changes in zeta potential may also play an important role. In addition, this solvent choice enables the true universality of QD EPD to be demonstrated, via the sensitization of porous TiO2 electrodes with a range of ligand capped CdSe QDs and a range of group II-VI CQDs including CdS, CdSe/CdS, CdS/CdSe and CdTe/CdSe, and group IV-VI PbS QDs.
关键词： dichloromethane,sensitization,photoanode,quantum dots,electrophoretic deposition
更新于2025-09-12 10:27:22
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Imidodiphosphonate Ligands for Enhanced Sensitization and Shielding of Visible and Near-Infrared Lanthanides
摘要： The design of coordination sites around lanthanide ions has a strong impact on the sensitization of luminescent signal. An imidodiphosphonate anionic binding site is attractive as it can be functionalized with “remote” sensitizer units, such as phenoxy moieties, namely, HtpOp, accompanied by an increased distance of the lanthanide from the ligand high-energy stretching vibrations which quench the luminescence signal, hence providing flexible shielding of the lanthanide. We report the formation and isolation of Ln(tpOp)3 complexes where Ln = Er, Gd, Tb, Dy, Eu, and Yb and the Y(tpOp)3 diamagnetic analogue. The complexes are formed from reaction of KtpOp and the corresponding LnCl3·6H2O salt either by titration and in situ formation or by mixing and isolation. All complexes are seven-coordinated by three tpOp ligand plus one ethanol molecule, except for Yb(tpOp)3 which has no solvent coordinated. Phosphorus NMR shows characteristic shifts to support the coordination of the lanthanide complexes. The complexes display visible and near-infrared luminescence with long lifetimes even for the near-infrared complexes which range from 3.3 μs for Nd(tpOp)3 to 20 μs for Yb(tpOp)3. The ligand shows more efficient sensitization than the imidodiphosphinate analogues for all lanthanide complexes with a notable quantum yield of the Tb(tpOp)3 complex at 45%. We attribute this to the properties of the remote sensitizer unit and its positioning further away from the lanthanide, eliminating quenching of high energy C?H vibrations from the ligand shell. Calculations of the ligand shielding support the photophysical properties of the complexes. These results suggest that these binding sites are promising in the further development of the lanthanide complexes in optoelectronic devices for telecommunications and new light emitting materials.
关键词： sensitization,imidodiphosphonate,shielding,luminescence,lanthanide
更新于2025-09-12 10:27:22
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1,5-Naphthyridine-based conjugated polymers as co-sensitizers for dye-sensitized solar cells
摘要： 1,5-naphthyridine-based conjugated polymers (P1 and P2) were synthesized and extensively characterized by 1H NMR, thermogravimetric analysis (TGA), FT-IR. These polymers were employed as co-sensitizers in DSSCs sensitized with Ru (II) based N3 dye. In comparison to the N3 sensitized device, the P1 and P2 co-sensitized solar cells demonstrated enhanced open circuit voltage, (VOC) of 825 and 788 mV and better ?ll factor (FF) of 59 and 58%, respectively. The co-sensitization of P1 and P2 with N3 increased the overall e?ciencies to 5.88% and 6.21%, respectively, as compared to 5.58% for N3 sensitizer alone. The fabricated device based on N3 co-sensitized with P2 displayed higher charge recombination resistances as compared to the devices based on N3 alone or N3 co-sensitized with P1. The conjugated polymers are believed to enhance light harvesting ability and reduce the charged recombination in the co-sensitized solar cells.
关键词： 1,5-Naphthyridine-based conjugated polymers,Solar cell,Co-sensitization,N3 dye
更新于2025-09-11 14:15:04
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Carboxylic Acid Functionalization at the Meso-Position of the Bodipy Core and Its Influence on Photovoltaic Performance
摘要： Two bodipy dyes with di?erent carboxylic acids on the meso-position of the bodipy core were prepared and used to sensitize TiO2 photoelectrodes. On the basis of spectroscopic characterization, the photoelectrodes were used to fabricate photoelectrochemical cells (PECs) for solar light harvesting. Photovoltaic measurements showed that both bodipy dyes successfully sensitized PECs with short-circuit current densities (JSC) two-fold higher compared to the control. The increase in generated current was attributed to the gain in spectral absorbance due to the presence of bodipy. Finally, the in?uence of co-sensitization of bodipy and N719 dye was also investigated and photovoltaic device performance discussed.
关键词： Dye-sensitized solar cells,photoelectrochemical cells,N719 dye,co-sensitization,bodipy dye
更新于2025-09-11 14:15:04
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Novel indeno[1,2-b]indole-spirofluorene donor block for efficient sensitizers in dye-sensitized solar cells
摘要： Indeno[1,2-b]indole-spirofluorene (IISF) unit has been synthesized and firstly applied as a donor candidate for the sensitizer of dye-sensitized solar cells. Two new dyes JY57 and JY58, based on IISF donor, are consequently constructed, together with dithieno[3,2-b:2',3'-d]pyrrole (DTP) as π-bridge and cyanoacrylic acid as acceptor. For JY58, additional electron-withdrawing 2,1,3-benzothiadiazole unit is inserted between IISF donor and DTP π-bridge to achieve a broader absorption range. Both dyes show high JSC and good device performance in iodine electrolyte. The photovoltaic properties are further tuned by co-adsorption and co-sensitization strategies, and better PCEs are obtained. Among the series of cells under AM 1.5G irradiation, cells fabricated by the synergic adsorption of JY57, chenodeoxycholic acid and JY59, achieve the highest PCE of 9.56%, which is much higher than 8.46% for N719 at the same condition.
关键词： Metal-free organic sensitizers,Synergy of co-sensitization and co-adsorption,Dye sensitized solar cells,Indeno[1,2-b]indole-spirofluorene donor
更新于2025-09-11 14:15:04