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N-doped C/CoSe2@Co–FeSe2 yolk-shell nano polyhedron as superior counter electrode catalyst for high-efficiency Pt-free dye-sensitized solar cell
摘要： Yolk-shell structures based on transition metal chalcogenides (TMCs) have broad application prospects in energy conversion/storage fields. In this work, a facile step-wise synthetic strategy was used to synthesize the yolk-shell structured polyhedrons. The intermediate named as ZIF-67@Co-Fe PBA nanocrystal was formed by the reaction between Co2+ released from ZIF-67 polyhedrons and [Fe(CN)6]3? hydrolyzed from K3[Fe(CN)6]. N-doped carbon/CoSe2@Co-FeSe2 (CoSe2-NC@Co-FeSe2) and N-doped carbon/CoS2@Co-FeS2 (CoS2-NC@Co-FeS2) polyhedrons with yolk-shell structures were prepared by modifying the ZIF-67@Co-Fe PBA nanocrystals in the annealing process and they have been applied in dye-sensitized solar cells (DSSCs). Noteworthily, CoSe2-NC@Co-FeSe2 and CoS2-NC@Co-FeS2 yolk-shell polyhedrons showed high catalytic activity in accelerating the reduction of triiodide in DSSCs because of the distinctive structural characteristics and favorable chemical compositions. The power conversion efficiency (PCE) of 9.61% and 9.18% were obtained by CoSe2-NC@Co-FeSe2 and CoS2-NC@Co-FeS2 based DSSCs, respectively, which were both superior to that of Pt (8.15%). This as-designed approach implies the new perspective to prepare more types of TMCs with yolk-shell structures in multitudinous areas of energy conversion.
关键词： CoSe2-NC@Co-FeSe2,Transition metal selenides,Yolk-shell polyhedrons,CoS2-NC@Co-FeS2,Dye-sensitized solar cells
更新于2025-09-11 14:15:04
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Clitoria ternatea flower as natural dyes for Dye-sensitized solar cells
摘要： Clitoria ternatea flowers have been investigated as a natural sensitizer in Dye-sensitized solar cell (DSSC). Dried C. ternatea flowers ware immersed in ethanol for 48 hours in dark room to obtain anthocyanin pigments. We compared the photovoltaic performance of the sensitizers with Titanium dioxide (TiO2) only and TiO2 with scattering layers. C. ternatea dyes have higher Power Conversion Efficiency (PCE) when applied in TiO2 with scattering layers compared to standard TiO2 semiconductors. Scattering layer (SL) has increased the light path inside the photo-anode film that doubled the short-circuit current (Jsc) and enhanced the open circuit voltage (Voc) compared to TiO2 based cell without the SL. In conclusion, from the result, higher electron injections can be achieved by light management on photo-anode film with scattering layers as one of strategy to enhance the efficiency for further low cost and environment-friendly solar cell.
关键词： Dye-sensitized solar cells,Clitoria ternatea,TiO2,scattering layers,natural dyes
更新于2025-09-11 14:15:04
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Influence of π spacer of donor-acceptor-π-acceptor sensitizers on photovoltaic properties in dye-sensitized solar cells
摘要： On the basis of organic dyes (E)-3-(6-(7-(bis(4-methoxyphenyl)amino)benzo[c] [1,2,5]thiadiazol-4-yl)-4,4-dimethyl-4H-cyclopenta[2,1-b:3,4-b']dithiophen-2-yl)-2-cyanoacrylic acid (1) and (E)-3-(6-(7-(bis(4-methoxyphenyl)amino)benzo[c] [1,2,5]thiadiazol-4-yl)-4-methyl-4H-dithieno[3,2-b:2′,3′-d]pyrrol-2-yl)-2-cyanoacrylic acid (2), two new D-A-π-A dyes, (E)-3-(7-(7-(bis(4-methoxyphenyl)amino)benzo[c] [1,2,5]thiadiazol-4-yl)benzo [2,1-b:3,4-b']dithiophen-2-yl)-2-cyanoacrylic acid (3) and (E)-3-(9-(7-(bis(4-methoxyphenyl)amino)benzo[c] [1,2,5]thiadiazol-4-yl)-2,3-dihydrodithieno[3′,2':3,4; 2″,3'':5,6]benzo[1,2-b] [1,4]dioxin-6-yl)-2-cyanoacrylic acid (4) are designed with diphenylamine as donor, 2-cyanoacrylic acid as acceptor along with different π group. Besides the frontier orbital energy levels and absorption spectra, the interfacial properties of dye-TiO2 adsorbed system is considered. After adsorption, the energy level of both dye and TiO2 surface shifts, which would affect the overall performance. More important, the short-circuit current density (JSC), open-circuit voltage (VOC), and photon-to-electron conversion efficiency (PCE) are calculated, which is helpful to determine the effect of π group on the donor-acceptor-π-acceptor dyes. The negative influence of aggregation for the dye-TiO2 adsorbed system is also considered to evaluate the overall photovoltaic performance. The molecular simulations are carried out to explore the dynamic properties of aggregation.
关键词： Dye sensitized solar cells,Molecular dynamics simulations,Photon-to-electron conversion efficiency,Electronic coupling,Aggregation
更新于2025-09-11 14:15:04
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Synthesis, characterization, and application of transition metals (Ni, Zr, and Fe) doped TiO2 photoelectrodes for dye-sensitized solar cells
摘要： In this paper, we present the synthesis of different metal-doped TiO2 compounds (pure TiO2, Fe doped TiO2 (FexTi1-xO2), Ni doped TiO2 (NixTi1-xO2), Zr doped TiO2 (ZrxTi1-xO2)) thin films in order to improve the performance of dye-sensitized solar cell (DSSC). Undoped TiO2 particles and Ni, Fe and Zr transition metals doped TiO2 particles were synthesized by the sol-gel method for the utilization of the anodic part of the DSSC. The cathode of the DSSC was a carbon electrode. Fluorine Doped Tin Oxide (FTO) coated electrodes on the glass surfaces and electrolyte solution containing I/I2 was obtained a dye-sensitized solar cell. Pure TiO2 and Ni, Fe and Zr doped TiO2 nanopowders were characterized by DLS, XRD, SEM/EDX, and UV-Vis Spectroscopy. The thin films have been deposited on the glass substrate by the doctor blade method. The effect of synthesized nano-materials on the cell performance of DSSC were investigated by J-V curves. J-V characterization of solar cell module shown that the highest power conversion efficiency was the solar cell module that fabricated with 10% of Zr-doped TiO2 with the short circuit current (Jsc) and the efficiency was at 0.13 mA cm-2 and 0.020%, respectively. However, yields on the cell performance of other nanomaterials were obtained as 0.019%, 0.017% and 0.015% for pure TiO2, Fe doped TiO2, and Ni doped TiO2, respectively.
关键词： TiO2 nanoparticles,dye-sensitized,Solar cells,sol-gel
更新于2025-09-11 14:15:04
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Self‐Assembled Graphene/MWCNT Bilayers as Platinum‐Free Counter Electrode in Dye‐Sensitized Solar Cells
摘要： We describe the preparation and properties of bilayers of graphene- and multi-walled carbon nanotubes (MWCNTs) as an alternative to conventionally used platinum-based counter electrode for dye-sensitized solar cells (DSSC). The counter electrodes were prepared by a simple and easy-to-implement double self-assembly process. The preparation allows for controlling the surface roughness of electrode in a layer-by-layer deposition. Annealing under N2 atmosphere improves the electrode’s conductivity and the catalytic activity of graphene and MWCNTs to reduce the I3? species within the electrolyte of the DSSC. The performance of different counter-electrodes is compared for ZnO photoanode-based DSSCs. Bilayer electrodes show higher power conversion efficiencies than monolayer graphene electrodes or monolayer MWCNTs electrodes. The bilayer graphene (bottom)/MWCNTs (top) counter electrode-based DSSC exhibits a maximum power conversion efficiency of 4.1 % exceeding the efficiency of a reference DSSC with a thin film platinum counter electrode (efficiency of 3.4 %). In addition, the double self-assembled counter electrodes are mechanically stable, which enables their recycling for DSSCs fabrication without significant loss of the solar cell performance.
关键词： graphene flakes,double self-assembly process,MWCNTs,counter electrode,dye-sensitized solar cells
更新于2025-09-11 14:15:04
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Epitaxial Growth of Highly Transparent Metal–Porphyrin Framework Thin Films for Efficient Bifacial Dye-Sensitized Solar Cells
摘要： Bifacial Dye-Sensitized Solar cells (DSSCs) are regarded as promising solar energy conversion devices with high efficiency and less resource consumption. In this work, a highly transparent and efficient counter electrode (CE) is fabricated by introducing highly-dispersed single Pt atoms doping into van der Waals layer-by-layer (lbl) epitaxial growth of Zn-TCPP thin film (Zn-TCPP-Pt). The resulted Zn-TCPP-Pt CE has similar catalytic activity to commercial Pt CE, but show a better light transmission capacity in the range of visible light. The bifacial DSSC with Zn-TCPP-Pt thin film CE achieves high power conversion efficiency (PCE) of 5.48% and 4.88% under front-side and rear-side irradiations, respectively. With maximized atomic efficiency, excellent performance was obtained with about 1% Pt content and highly-transparent CEs. Therefore, the light energy resource utilization rate of such less Pt and transparence CE is greatly improved in bifacial dye-sensitized solar cells, making it a promising candidate to replace Pt CE.
关键词： Bifacial dye-sensitized solar cells,Oriented Thin Film,Metal-Organic Frameworks,Counter Electrode,van der Waals Epitaxial Growth
更新于2025-09-11 14:15:04
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Significant Influence of a Single Atom Change in Auxiliary Acceptor on Photovoltaic Properties of Porphyrin-Based Dye-Sensitized Solar Cells
摘要： The rational design of porphyrin sensitizers is always crucial for dye-sensitized solar cells (DSSCs), since the change of only a single atom can have a signi?cant in?uence on the photovoltaic performance. We incorporated the pyridothiadiazole group, as a stronger electron-withdrawing group, into the commonly well-established skeleton of D-porphyrin-triple bond-acceptor sensitizers by a single atom change for a well-known strong electron-withdrawing benzothiadiazole (BTD) unit as an auxiliary acceptor. The impact of the pyridothiadiazole group on the optical; electrochemical; and photovoltaic properties of D–π–A porphyrin sensitizers was investigated with comparison for a benzothiadiazole-substituted SGT-020 porphyrin. The pyridothiadiazole-substituted SGT-024 porphyrin dye was red-shifted so that the absorption range might be expected to achieve higher light harvest ef?ciency (LHE) than the SGT-020 porphyrin. However, all the devices were fabricated by utilizing SGT-020 and SGT-024, evaluated and found to achieve a cell ef?ciency of 10.3% for SGT-020-based DSSC but 4.2% for SGT-024-based DSSC under standard global AM 1.5G solar light conditions. The main reason is the lower charge collection ef?ciency of SGT-024-based DSSC than SGT-020-based DSSC, which can be attributed to the tilted dye adsorption mode on the TiO2 photoanode. This may allow for faster charge recombination, which eventually leads to lower Jsc, Voc and power conversion ef?ciency (PCE).
关键词： charge collection ef?ciency,dye-sensitized solar cells,D–π–A structural porphyrin,acceptor units,charge recombination
更新于2025-09-11 14:15:04
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Study of charge injection in Ortho-, Meta- and Para-NKX-2553 in Dye-Sensitized Solar Cells: A theoretical approach
摘要： Dye sensitizers due to their significant role in the efficiency of Dye-Sensitized Solar Cells (DSSCs) have become the focal center of interest in recent years. In this study, NKX-2553 as one of the appealing metal-free organic dyes in different configurations of Ortho, Meta, and Para has been investigated. Parameters such as geometries, electronic structures, and optical properties, along with dipole moment, polarizability and first-order hyperpolarizability were calculated using density functional theory (DFT) and time-dependent DFT (TD-DFT). Results show that the Para-NKX-2553 is the best configuration in respect of increasing the charge injection in DSSCs. Moreover, according to our study, the efficiency of DSSCs can be improved through applying an external electric field in an appropriate direction.
关键词： Electric field,Charge injection,DFT,TD-DFT,Dye-sensitized solar cells,Electronic structure
更新于2025-09-11 14:15:04
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Electronic Structures and Catalytic Activities of Niobium Oxides as Electrocatalysts in Liquid Junction Photovoltaic Devices
摘要： Two types of nanosized niobium oxides and their composite: pseudo-hexagonal Nb2O5 (TT-Nb2O5), monoclinic NbO2 (M-NbO2) and the coexistence of TT-Nb2O5 and M-NbO2 (TT-Nb2O5/M-NbO2) are successfully synthesized through the urea-metal chloride route, and they exhibit excellent catalytic activity and photovoltaic performance in dye-sensitized solar cells (DSSCs). First-principles density function theory (DFT) calculations show that their catalytic activity is significantly influenced by their intrinsic electronic structures and properties. The lone-pair 4d1 electrons of Nb4+ in M-NbO2 enhance the Nb-I interaction and promote the electron transfer from the M-NbO2 counter electrode (CE) to I, and thus resulting in superior catalytic properties in M-NbO2 based DSSCs. In addition, the adsorption energy of I on the M-NbO2 surface is in the optimal energy range of 0.3?1.2 eV, and the Fermi level of M-NbO2 is 0.6 eV, which is higher than the I3? reduction reaction (IRR) potential and I3? can be spontaneously reduced to 3I?. This work provides a general strategy for understanding the electronic structures and catalytic activities of transition metal compounds as CE catalysts for DSSCs.
关键词： electrocatalytic activity,counter electrodes,first-principles DFT calculations,dye-sensitized solar cells,niobium oxides
更新于2025-09-11 14:15:04
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Effect of electron donor and acceptor in dithienopyrrolobenzothiadiazole-based organic dyes for efficient quasi-solid-state dye-sensitized solar cells
摘要： Three new organic dyes H1-3 with dithienopyrrolobenzothiadiazole moiety as the π-bridge have been synthesized and applied in quasi-solid-state dye-sensitized solar cells. The influences of different electron acceptor of the sensitizers on the photo-physical, electrochemical and photovoltaic performances have been studied. The results show that the inserted electron-withdrawing unit benzothiadiazole in the acceptor part can obviously enhance the light-harvesting ability of the dyes. In addition, the introduced benzothiadiazole moiety in acceptor can increase the π-electron distribution in LUMO level, which may facilitate to the photogenergated electrons injection into TiO2 film. The effects of different electron donor on the solar cell performances have been evaluated. The dihexyloxy substituted triphenylamine is better to suppress the intermolecular aggregation and restrain electron recombination. Finally, the quasi-solid-state solar cell sensitized by dye H2 with 1 mM chenodeoxycholic acid as the co-adsorbent obtains a power conversion efficiency of 7.56%, which close to the level of dye N719 (7.66%) under the same condition.
关键词： Benzothiadiazole,Electron donor,Quasi-solid-state dye-sensitized solar cells,Power conversion efficiency,Dithienopyrrolobenzothiadiazole
更新于2025-09-11 14:15:04