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Luminescence enhancement of spherical Sr3La(PO4)3:Eu3+ red nanophosphor with core–shell configuration and added sensitizer for low-voltage field-emission lamp
摘要： Spherical red Sr3La(PO4)3:Bi3+,Eu3+ (SLPO:Bi3+,Eu3+) nanophosphors were synthesized by coprecipitation and thermal annealing for a low-voltage field-emission lamp (FEL). The luminescence intensity of the phosphor was improved using a coreeshell configuration with SiO2 as the core with a diameter of 360 nm and 5e15-nm-thick phosphor as the shell. A 4.4-fold enhancement in the external quantum efficiency (EQE) was obtained. A bright red cathodoluminescence was observed from a 0.25-cm2 FEL at 400 V. The excitation energy efficiently cascade-transferred through the Bi3+ sensitizer to the Eu3+ activator. A coreeshell SLPO:Bi3+,Eu3+ nanophosphor with a maximum EQE of 25.4% and high color purity of 99.7% was obtained when 5-mol% Bi3+ was doped. The energy transfer mechanism and model of the phosphor are proposed.
关键词： Nanophosphor,Sensitizer,Field emission lamp,Coreeshell
更新于2025-09-23 15:23:52
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Modification of the electronic properties of the π-spacer of chromophores linked to calix[4]arene platform for DSSCs applications
摘要： We have developed two novel dyes based on p-tert-butyl-calix[4]arene in order to evaluate their behavior as sensitizer in photovoltaic devices. These dyes consist in a difunctionalized calix[4]arene with triphenylamine (TPA)-donor, a heteroaromatic π-conjugated spacer, thiophene and benzothiadiazole-phenyl ring, respectively and cyanoacetic acid as acceptor group. The effect of the p -spacer has been studied by UV-vis spectroscopy and Differential Pulse Voltammetry and the models compounds have been theoretically investigated. The dye bearing phenylbenzothiadiazole results in a bathochromic shifted absorption and an adequate efficiency to transfer charge from D to A. The considerable increase of the photocurrent density results in a better efficiency of the devices prepared with these novel dyes with respect to the p-tert-butyl-calix[4]arene derivatives bearing TPA dye. In particular, p-tert-butyl-calix[4]arene derivative based on phenylbenzothiadiazole has reached an efficiency value of 5.84 % which means an increase of 33 % of the efficiency over those calix[4]arene derivatives with TPA dye.
关键词： aggregation,calix[4]arene,multichromophore,benzothiadiazole,metal-free sensitizer
更新于2025-09-23 15:23:52
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Adsorption and Cation Exchange Behavior of Zinc Sulfide (ZnS) on Mesoporous TiO2 Film and Its Applications to Solar Cells
摘要： Zinc sulfide (ZnS) was deposited onto the surface of mesoporous TiO2 film by a typical successive ionic layer adsorption and reaction (SILAR) process. By inducing a spontaneous cation exchange between ZnS and a target cation (Pb2+, Cu2+, Ag+, or Bi3+) dissolved in chemical bath when they are in contact, it was demonstrated successfully that white translucent ZnS on the substrate could be changed to brown-colored new metal chalcogenides and the amount of ZnS deposited originally by different conditions could be compared in a qualitative way with the degree of the color change. By utilizing this simple but effective process, the evolution of well-known ZnS passivation layer prepared from different chemical baths in quantum dot (QD)-sensitized solar cells could be tracked visually via checking the degree of color change of TiO2/ZnS electrodes after the induced specific cation exchange. When applied to representative CdS QD-sensitized solar cells, it was revealed clearly how the different degree and rate of ZnS deposition could affect the overall power conversion efficiency while finding an optimized passivation layer over TiO2/CdS electrode. Acetate anion-coupled Zn2+ source was observed to give a much faster deposition of ZnS passivation layer than nitrate anion one due to its higher pH-induced more favorable adsorption of Zn2+ on the surface of TiO2. As another useful application of the ZnS-based cation exchange, as-deposited ZnS was used as a template for preparing a more complex metal chalcogenide onto mesoporous TiO2 film. The ZnS-derived Sb2S3-sensitized electrode showed a promising initial result of over 1.0 % overall power conversion efficiency with a very thin ZrO2 passivation layer between TiO2 and Sb2S3.
关键词： passivation,Quantum dot-sensitizer,SILAR deposition,zinc sulfide,solar cell,cation exchange
更新于2025-09-23 15:21:01
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High Performances Thermally Activated Delayed Fluorescence Organic Light-emitting Diodes with Wide Gap Phosphorescent Complex as Sensitizer
摘要： In this work, we demonstrated the high performances electroluminescent (EL) devices based on orange-yellow thermally activated delayed fluorescence emitter (TXO-TPA) by utilizing an iridium complex (FK306) as sensitizer. Compared with reference devices without FK306, these co-doped devices displayed significant enhancement of EL performances, which could be attributed to optimized carriers' distribution and efficient energy transfer. In addition, the presence of FK306 molecules helps to broaden the exciton formation zone in EML2, thus suppressing the quenching of triplet excitons. Finally, the optimized co-doped double-EMLs device obtained superior EL performances with maximum current efficiency, power efficiency and external quantum efficiency up to 58.94 cd/A, 61.69 lm/W and 16.5%, respectively. Even at the high brightness of 1000 cd/m2, EL efficiency as high as 12.67 cd/A can still be retained by the same device.
关键词： Organic Light-emitting Diodes,Sensitizer,Wide Gap Phosphorescent Complex,Thermally Activated Delayed Fluorescence
更新于2025-09-23 15:21:01
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Harnessing sun for catalyst and sensitizer free regio- and stereo-selective [2+2] cycloaddition
摘要： Presence of cyclobutane rings in bioactive natural products makes them a popular synthetic target. Most common strategy for synthesizing cyclobutanes is [2+2] cycloaddition, which is usually facilitated by using ultraviolet radiation and catalysts. Herein we report the design and synthesis of densely functionalized cyclobutanes by alleviating these drawbacks and using sunlight. Further, we identified the putative mechanism of the transformation based on kinetic, fluorescence and crystallographic studies and evaluated biological activities of the products against MCF7 cell lines. The rational design of the olefinic substrates was based on their UV-vis spectra. The generic aspect of the reaction was elucidated by the syntheses of diverse analogs of cyclobutanes. Further, crystal structures and UV-vis spectra of the olefinic partners assisted us in rationalizing the stereoselectivity of the heterodimers. We believe this energy-efficient mild approach will provide a substantial contribution to the existing repertoire of strategies to regio- and stereoselectively access cyclobutanes.
关键词： Cycloaddition,Photocatalysis,Photodimerization,Self-sensitizer,Regio-selectivity
更新于2025-09-23 15:21:01
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First Report of Chenodeoxycholic Acida??Substituted Dyes Improving the Dye Monolayer Quality in Dyea??Sensitized Solar Cells
摘要： Chenodeoxycholic acid (CDCA) is the most used antiaggregation additive in dye-sensitized solar cells since its introduction to the field in 1993. However, effective suppression of dye aggregation comes at the cost of reduced dye loading, a lower open-circuit voltage, and limited control of dye/additive distribution when cosensitizing with free CDCA. To combat this, herein, a novel dye design concept that uses the covalent attachment of a CDCA moiety to triarylamine sensitizers is reported. The CDCA substituents do not affect the photophysical or electrochemical properties of the sensitizers but have a positive effect on the photovoltaic performance with [Cu(tmby)2](TFSI)1/2 electrolyte (tmby = 4,4',6,6'-tetramethyl-2,2'-bipyridine, TFSI = bis(trifluoromethanesulfonyl)imide). By ensuring a one-to-one ratio of dye and CDCA, paired with isotropic distributions of each component, this approach results in a higher-quality dye monolayer. Compared with the reference system, the novel approach reported herein gives a higher open-circuit voltage and power conversion efficiency (PCE). The best device is fabricated with the dye C6–CDCA, delivering a PCE of 6.84% (8 μm TiO2, 1 mM CDCA, JSC = 8.64 mA cm?2, VOC = 1007 mV, and FF = 0.77).
关键词： dye design,dye distributions,sensitizer quantum efficiencies,chenodeoxycholic acid,antiaggregation
更新于2025-09-23 15:19:57
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Performance enhancement of dye-sensitized solar cells via co-sensitization of ruthenium (II) based N749 dye and organic sensitizer RK1
摘要： The aim of the reported study is to enhance the photovoltaic performance of a dye-sensitized solar cells (DSSCs) using co-sensitization approach and investigate how the concentration of an organic co-sensitizer influence the overall efficiency of the fabricated DSSCs. The overall efficiency of the fabricated DSSC with co-sensitization approach using a ruthenium (II) based dye, N749, and an organic sensitizer, RK1, is 8.15%. The solar cells were evaluated using UV–Vis spectroscopy, electrochemical impedance spectroscopy (EIS), incident photon to electron conversion efficiency (IPCE), and current-voltage (I-V) characteristics. The concentration of the organic co-sensitizer has a strong effect on the performance of the DSSC. An optimized solar cell fabricated with a dye solution of 0.2 mM RK1 and 0.3 mM N749 yielded a Jsc (mA/cm2) = 19.45, Voc (mV) = 688, FF (%) = 61 and power conversion efficiency (PCE) of η (%) = 8.15 under standard (AM1.5 G) 1 sun illumination (100 mW/cm2). The efficiency of co-sensitized DSSCs is far better than the efficiency of fabricated solar cells sensitized with individual dyes [N749 (η = 4.94%) and RK1 (η = 5.76%)]. The efficiency enhancement is due to the lower rate of recombination of electrons and holes, decreased I?/I3? competitive absorption, and lower aggregation of the dyes resulting from the synergistic action in the co-sensitized photovoltaic cells.
关键词： Co-sensitization,Efficiency,Ruthenium (II) based dye (N749),Photovoltaic,Organic Sensitizer (RK1),DSSC
更新于2025-09-23 15:19:57
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Natural Dyes from Morti?±o (Vaccinium floribundum) as Sensitizers in Solar Cells
摘要： Photovoltaic energy presents environmental advantages; however, these advantages are limited by the cost of manufacturing solar cells and in many cases, scarce or dangerous materials are incorporated. Therefore, the use of natural dyes from morti?o (Vaccinium ?oribundum) as sensitizers in solar cells is proposed. The dyes were extracted by maceration in acidi?ed methanol (HCl, citric acid and tri?uoroacetic acid TFA) and were characterized by High-Performance Liquid Chromatography (HPLC), Thin-Layer Chromatography (TLC) and spectrometric methods (UV-Vis, IR and MS-MALDI). The construction and characterization of cells were in standard conditions. The study con?rms that pigments in morti?o are ?avonoids of the anthocyanidin group as: cyanidin-3-galactoside, and cyanidin-3-arabinoside. The e?ciency of solar cells was between 0.18–0.26%; the extraction with TFA in methanol leads to the best performance. Although they have low power conversion e?ciency, morti?o dyes could be an alternative to arti?cial sensitizers for solar cell technologies because they are harmless and abundant substances.
关键词： morti?o,e?ciency,solar cells,sensitizer,anthocyanins,dye
更新于2025-09-19 17:13:59
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Upconversion System with Quantum Dots as Sensitizer: Improved Photoluminescence and PDT Efficiency
摘要： Upconversion nanoparticles (UCNPs) are prospective platforms for bioimaging and phototherapy, but a critical bottleneck is the limited brightness due to the faint absorptivity of lanthanide ions and the low quantum yield. To circumvent this problem, we herein propose our strategy to reconstruct the energy cascade of UCNPs, using semiconductor quantum dots (QDs) as light sensitizer of Nd3+/Yb3+ co-doped UCNPs. Ag2Se QDs with strong absorption at 808 nm acted as efficient antenna and transferred their energy to Yb3+ via a resonance energy transfer process, significantly enhancing the luminescence of UCNPs. This nanocomposite was then combined with Rose Bengal and applied for photodynamic therapy. Both in vitro and in vivo studies revealed the introduction of QDs improved the therapeutic performance remarkably. Our study suggests Ag2Se QDs with excellent photophysical properties can be promising agents to overcome the shortcomings of UCNPs and further strengthen their applications.
关键词： quantum dots,sensitizer,upconversion,photodynamic therapy,photoluminescence efficiency
更新于2025-09-19 17:13:59
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Application of carbon dots in dye‐sensitized solar cells: A review
摘要： Carbon dots (CDs) are a kind of zero-dimensional carbon-based nanoparticles with superb light-trapping ability, high optical absorption ability, and superior intrinsic catalytic activity. Due to these advantageous properties, they have received enthusiastic attention from researchers in the field of optical devices. The application of carbon dots in dye-sensitized solar cells has increased with steady steps recently, especially as a substitute for precious Ru-sensitizers and Pt counter electrodes. In this review, we classified the application of carbon dots in dye-sensitized solar cells in recent years and explained the mechanisms of improving the performance of carbon dots. The significant impact of surface functionalization of CDs on the performance of dye-sensitized solar cells was discussed. Lastly, some challenges and application prospects of carbon dots in the dye-sensitized solar cell were proposed, which is meaningful for the further exploration and application of carbon dots as a new energy material.
关键词： sensitizer,counter electrode,carbon dots,surface functionalization,dye-sensitized solar cells
更新于2025-09-19 17:13:59