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Excited State Dynamics of [Ru(bpy)3]2+ Thin Films on Sensitized TiO2 and ZrO2
摘要： The excited state dynamics of Tris(2,2'-bipyridine)ruthenium(II) hexafluorophosphate, [Ru(bpy)3(PF6)2], was investigated on the surface of bare and sensitized TiO2 and ZrO2 films. The organic dyes LEG4 and MKA253 were selected as sensitizers. A Stern-Volmer plot of LEG4-sensitized TiO2 substrates with a spin-coated [Ru(bpy)3(PF6)2] layer on top shows considerable quenching of the emission of the latter. Time-resolved emission spectroscopy interestingly reveals the presence of a fast-decay time component (25±5 ns), which is absent when the anatase TiO2 semiconductor is replaced by ZrO2. It should be specified that the positive redox potential of the ruthenium complex prevents electron transfer from the [Ru(bpy)3(PF6)2] ground state into the oxidized sensitizer. Therefore, we speculate that the fast-decaying time component observed may be identified with excited-state electron transfer from [Ru(bpy)3(PF6)2] to the oxidized sensitizer. Solid-state dye sensitized solar cells (ssDSSCs) employing MKA253 and LEG4 dyes, with [Ru(bpy)3(PF6)2] employed as a hole-transporting material (HTM), exhibit 1.2% and 1.1% power conversion efficiency, respectively. This result illustrates the possibility of the hypothesized excited-state electron transfer.
关键词： Photochemistry,Excited-state electron transfer,DSSCs,Ru(bpy)3,Solid state
更新于2025-09-23 15:23:52
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Quantum chemical investigation of modified coumarin-based organic efficient sensitizers for optoelectronic applications
摘要： One of the most major features in the improvement of dye-sensitized solar cells (DSSCs) is the survey and plan of high-efficiency and low-cost dyes. In this paper, a new series of metal-free coumarin-based (NKX-2311) dye molecules, namely (D1–D4) are investigated for use in DSSC applications. The dye molecules contain three parts, electron-donor (D) connected by the π-conjugated linker as a spacer and electron-acceptor (A)/anchoring group. Molecular structure, electronic absorption spectra and photovoltaic (PV) parameters of the D1–D4 dyes have been performed by using density functional theory (DFT) and time-dependent DFT (TD-DFT) approaches are employed. The effects of chemical modification on the spectra and PV properties of the coumarin-modified organic dyes have been revealed. The performance of three functionals (B3LYP, CAM-B3LYP and ωB97XD) has been evaluated to get an experimental absorption wavelength of NKX-2311. From the functionals, B3LYP method was better matched with the absorption wavelength of NKX-2311. Therefore, D1–D4 dye molecules excited state calculations of the absorption spectra have been investigated by using B3LYP functional with 6-31G(d) basis set. The results show that D1, D3 dyes are smaller energy gap and absorption spectra are systematically red-shifts. The theoretical results have a display that the lowest occupied molecular orbitals (LUMOs) and highest occupied molecular orbitals (HOMOs) of the D1–D4 dyes can be confirming positive response on the electron injection and dye regeneration process. The NLO property of the D1–D4 dyes can be derived as polarizability and first-order hyperpolarizability. The calculated values of D1 and D3 dyes are the best applicants for NLO performance. The conclusion of this study will deliver a useful reference to the future proposal and beneficial to get DSSCs with superior power conversion efficiency (PCE).
关键词： TD-DFT,coumarin-based dyes,DSSCs,NLO properties,DFT,photovoltaic properties
更新于2025-09-23 15:21:01
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Sustainable Organic Dyes from Winemaking Lees for Photoelectrochemical Dye-Sensitized Solar Cells
摘要： During the last two decades, Dye Sensitized Solar Cells (DSSCs) have received a great deal of attention as a promising, low-cost alternative to conventional silicon photovoltaic devices. Natural dye molecules can be used as a sensitizer for their low cost, good light absorbance, easy preparation process, and biodegradability. In this study, dyes were obtained from wine lees, the last by-product of winemaking process, supplied by a venetian winery (Italy). Polyphenols, like tannins and anthocyanins, which were extracted from winemaking lees, were adsorbed on a nanostructured ordered mesoporous titanium dioxide, previously treated at different temperatures (400–600 °C). Both dyes and titania semiconductor samples were studied with different techniques. The tests were carried out on prototypes to evaluate the cell power and the photocurrent generated under simulated solar light irradiation. The obtained solar energy conversion efficiencies are comparable to those that were reported in literature by using organic dyes extracted from vegetables, fruits, and plants. It is significant that these dyes are largely available and cost effective, since recovered from a waste otherwise to be disposed of, opening up a perspective of feasibility for inexpensive and environmentally friendly dye solar cells to generate green electricity and transforming agri-food waste into a resource.
关键词： circular economy,organic dyes,titania nanoparticles,winemaking lees,DSSCs
更新于2025-09-23 15:21:01
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Theoretical and Conceptual Framework to Design Efficient Dye-Sensitized Solar Cells (DSSCs): Molecular Engineering by DFT Method
摘要： Herein, eight new donor-p-acceptor organic dyes namely M1–M8 have been theoretically investigated for their potential in optoelectronic properties. The M1–M8 were designed through structural modi?cation of p-conjugated bridge of reference reported molecule IC2. The designed molecules contain Indolo[3,2,1-jk]carbazole as core donor unit and end capped cyanoacrylic acid as acceptor unit. DFT and TDDFT calculations using B3LYP, CAM-B3LYP, xB97XD and M062X functional were performed to evaluate the photophysical and photovoltaic properties. Results indicate that HOMO–LUMO energy gaps in M1–M8 have been found smaller than IC2. Among all, M7 is a material with lowest energy gap 2.61 eV, red shifted absorption wavelength value 436 nm. Results of the calculated redox potential of the ground state, vertical excitation energy of the dye, oxidation potential of the dye in the excited state, free energy change for electron injection, dye regeneration and open circuit photovoltage and light harvesting ef?ciency indicates that p-bridges in M1–M8 would show better power conversion ef?ciency than IC2. Especially, dye M7 with p-bridge 5-(thiazol-5yl)thiazole is found to be the most promising candidate for highly effective DSSCs properties. This theoretical framework may provide new ways for experimentalists to design high-performance DSSCs materials for optoelectronic applications.
关键词： Molecular modeling,p-conjugated linkers,Indolo[3,2,1-jk]carbazole,DSSCs
更新于2025-09-23 15:21:01
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Design, Synthesis and Application of Imidazole-Based Organic Dyes in Dye Sensitized Solar Cells
摘要： Metal-free D–D–p–A type dyes (i.e., Car-Cy, Car-Rh, Dpa-Cy, and Dpa-Rh) were designed and synthesized for dye-sensitized solar cells (DSSCs). In the structure of the sensitized dyes, an imidazole ring is connected to a carbazole or diphenylamine moiety as a donor while cyanoacetic acid or rhodanine-3-acetic acid was introduced as an acceptor/anchor. The molecular structures of D–D–p–A type dyes were characterized using IR, NMR and MS spectral data. The optical, electrochemical, theoretical, light harvesting property, HOMO/LUMO levels, redox behavior, and photovoltaic properties of the synthesized dyes were evaluated. Among the fabricated photovoltaic devices based on the prepared dye, Dpa-Cy dye containing diphenylamine as a donor and cyanoacetic acid as an acceptor exhibited a high-power conversion efficiency of 1.70% with a short-circuit current density (JSC) of 4.48 mA cm?2, an open-circuit photovoltage (VOC) of 0.53 V and a fill factor of 72% under AM1.5 illumination (85 mW cm?2) in comparison with other dyes. Plane-wave calculations indicate that the dye binds reasonably strongly to the TiO2 surface, and the generated DOS picture shows an overlap of the molecular orbitals of the dye and the TiO2 bands. We conclude that the dyes have a promising role as sensitizers in DSSCs.
关键词： rhodanine-3-acetic acid,cyanoacetic acid,carbazole,DSSCs,diphenylamine
更新于2025-09-23 15:21:01
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Theoretical studies on D-A-??-A and D-(A-??-A)2 dyes with thiophene-based acceptor for high performance p-type dye-sensitized solar cells
摘要： Eight p-type dyes with D-A-π-A or D-(A-π-A)2 structures were designed to investigate the effect of thiophene derivatives acting as acceptors on the properties of the sensitizers. Structure optimizations were performed by the density functional theory (DFT) method, and the electronic and absorption characters were obtained with the time-dependent DFT (TD-DFT). The results show that all the eight dyes have an excellent light harvesting efficiency (LHE) performance (0.99–1.00). And the driving forces of hole injection (ΔGinj) and dye regeneration (ΔGreg) of all dyes are more negative than (cid:0) 0.2 eV, resulting in an efficient hole injection and dye regeneration. Furthermore, the dyes with 2,3-dimethylpyrazine thiophene moiety (DMPZT-1) have the narrowest energy gaps. Importantly, the dyes with DMPZT-1 moiety display red shifts of the UV–vis absorption and enhanced absorptions of visible light (400–800 nm) in comparison to their prototype. In addition, the charge recombination (ΔGCR) performance of A1 and B1 is improved by DMPZT-1. Compared with the D-A-π-A dyes, the additional -A-π-A chain in D-(A-π-A)2 could decrease energy gap further and improve the visible light adsorption, LHE, and driving forces for hole injection and charge regeneration (ΔGinj and ΔGreg). Replacing thiophene with DMPZT-1 acceptor is an effective way to improve the performance of the dyes.
关键词： DFT,p-type organic sensitizers,DSSCs,D-A-π-A,Thiophene derivatives
更新于2025-09-23 15:21:01
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Europium and terbium lanthanide ions co-doping in TiO2 photoanode to synchronously improve light-harvesting and open-circuit voltage for high-efficiency dye-sensitized solar cells
摘要： In this study, we explore the effects on the incorporation of europium (Eu3+) and terbium (Tb3+) rare-earth ions into titanium dioxide (TiO2) photoanodes in dye-sensitized solar cells (DSSCs). X-ray photoelectron spectroscopy (XPS) studies affirm that the Eu3+ ions are arranged at the cationic locales of Ti4+ in the matrix whereas the site inhabitance was remunerated by Tb3+ ions, supporting that the anatase phase stays unaltered without generating any new deformities. Additionally, the Eu3+ ions decidedly changed the conduction band minimum of TiO2, actually, Tb3+ ions contrarily conversion because of various vacant trap states in the band gap. Besides, the photoinduced electron transfer estimations show an efficient interfacial charge transfer for co-doped TiO2 (kET = 3.1 ns) contrasted with the bare TiO2 (2.6 ns). DSSCs based on Eu3+/Tb3+ co-doped TiO2 display higher efficiency (9.11%) than those for the bare TiO2 (7.20%) and the exclusively Eu3+ (8.01%) or Tb3+ (7.10%) doped samples, which is ascribed to the joined impact of a faster electron transportation and longer electron lifetime in the co-doped TiO2 film. This work may open another approach to further improve the performance of DSSCs by Eu3+/Tb3+ co-doping technique, advancing the development of DSSCs toward commercial applications.
关键词： Co-doping process,Europium (Eu3+)/terbium (Tb3+) lanthanide ions,Stability,Photoanodes,DSSCs,Titanium dioxide (TiO2) nanopowders
更新于2025-09-23 15:21:01
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Cu-BTC assisted DSSCs with improved photovoltaic performances
摘要： MOF based composite material is adopted to modify photoanode, and the obtained large BET area is found meaningful to the dye loading amount, which brings about a high short circuit current and incident photon to current conversion efficiency. Meanwhile, three-dimensional graphene networks (3DGNs) is employed to provide a fast transport channel for photo-induced electrons. The morphology is analyzed by SEM, TEM, XRD and Raman spectrum, and the photovoltaic performances are recorded to reveal the specific functions of MOF and 3DGNs. The synergy between MOF, 3DGNs and TiO2 is achieved by adjusting their mass fraction. Moreover, the average size of MOF exerts a significant influence on the resulting properties resulting from the scattering ability to incident light. After corresponding optimizing, the short circuit current, open circuit voltaic, fill factor and energy conversion efficiency reach 20.5 mAcm-2, 680 mV, 0.619 and 8.63%.
关键词： Cu-BTC,dye adsorption ability,three-dimensional graphene networks,DSSCs
更新于2025-09-23 15:19:57
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Influence of the meso-substituents of zinc porphyrins in dye-sensitized solar cell efficiency with improved performance under short periods of white light illumination
摘要： The sensitization activity of four zinc metalloporphyrin dyes: meso-tetrakis(4-pyridyl)porphyrinato Zn(II) (a), meso-triphenyl-(4-carboxyphenyl)porphyrinato Zn(II) (b), meso-tetrakis(4-carboxyphenyl)porphyrinato Zn(II) (c) and meso-tripyridyl(4-carboxyphenyl)porphyrinato Zn(II) (d) is reported here, in terms of current-potential curve, open-circuit potential, fill factor, and overall solar energy conversion efficiency which have been evaluated under 100 mW/cm2 light intensity and their performances compared to the benchmark N719 (di-tetrabutylammonium cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato) ruthenium(II). This work focus the structural aspects of dyes with anchoring groups using TiO2-based Dye Sensitized Solar Cells (DSSCs), which includes pyridyl and carboxyphenyl acid groups and argue how the combination of both anchoring groups, in the same structure, may allow relevant optimization of DSSCs performance in the near future. Also, a noticeable improvement in the photovoltaic performance of all dyes, reaching a maximum increase from 25% to 69% in the overall DSSC efficiency under short periods of white light illumination is discussed.
关键词： Dye sensitized solar cells (DSSCs),Macrocycles,Carboxylic acid anchoring group,Dyes,Photoconversion efficiency,TiO2,Metalloporphyrin
更新于2025-09-23 15:19:57
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Boosted Reactivity of Low-Cost Solar Cells over a CuO/Co <sub/>3</sub> O <sub/>4</sub> Interfacial Structure Integrated with Graphene Oxide
摘要： Developing cost-effective and environment-friendly counter electrodes (CEs) with high performance is central for the commercial application of dye-sensitized solar cells (DSSCs). In this work, the porous interfacial CuO/Co3O4@GO (CCO@GO) hybrid was fabricated by encapsulating the self-assembled CuO/Co3O4 nanosphere in graphene oxide (GO) and acted as a CE for the first time. Further measurements verified that the optimized CCO@GO hybrid not only provided a higher specific surface area (86.7 m2?g?1) with more exposed catalytic sites, but also significantly enhanced the power conversion efficiency (PCE = 8.34%) of DSSC, which was higher than that of the Co3O4-based CE (2.66%) and commercial Pt CE (7.85%). The results indicate that the interfacial CuO/Co3O4@GO hybrid synergistically accelerates the diffusion of I3?/I? redox couple and transmission of electrons, thus promoting the reaction kinetics. This work provides a remarkable way for exploring economical high-performance Pt-free CEs for DSSCs, as well as contributes to the further development for other energy-related fields.
关键词： DSSCs,interfacial structure,transition metal oxides,CuO/Co3O4@GO,counter electrode
更新于2025-09-23 15:19:57