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<i>In Situ</i> 2D Perovskite Formation and the Impact of the 2D/3D Structures on Performance and Stability of Perovskite Solar Cells
摘要： Hybrid organic and inorganic perovskite solar cells suffer from the lack of long-term stability and this negatively impacts the widespread application of this emerging and promising photovoltaic technology. In this work, aiming to increase the stability of perovskite films based on CH3NH3PbI3 and to deep understand the formation of 2D structures, solutions of alkylammonium chlorides containing 8, 10 and 12 carbons were introduced during the spin-coating on the surface of 3D perovskite films leading to the in situ formation of 2D structures. It was possible to identify the chemical formulae of some 2D structures formed by XRD and UV-Vis analysis of the modified films. Interestingly, the increase in the stability of the CH3NH3PbI3 films due to the formation of a 2D+3D perovskite network was only possible in planar TiO2 substrates. The increase on stability of the CH3NH3PbI3 films follows the surfactant molecule order: octylammonium (8C) > decylammonium (10C) > dodecylammonium (12C) chlorides > standard. We observed an increase of 17.6 % in the lifetime of the devices assembled with modified perovskite film compared to our standard device, which is directly linked to the improvement of the charge carrier lifetimes obtained from Time-Correlated Single Photon Counting (TCSPC) measurements.
关键词： Energy Conversion,Photovoltaics,Stability,2D perovskite,Perovskite Solar Cell
更新于2025-11-19 16:56:35
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Cu3MS4 (M=V, Nb, and Ta) and their solid solutions with sulvanite structure for photocatalytic and photoelectrochemical H2 evolution under visible light irradiation
摘要： Solid solutions with a sulvanite structure between Cu3VS4 and either Cu3NbS4 or Cu3TaS4 (Cu3Nb1-xVxS4, Cu3Ta1-xVxS4) were successfully prepared by a solid-state reaction. Their band gaps were 1.6–1.7 eV corresponding to the absorption of a wide range of visible light. Ru-cocatalyst loaded Cu3MS4 (M=V, Nb, Ta), Cu3Nb1-xVxS4, and Cu3Ta1-xVxS4 showed photocatalytic activities for sacrificial H2 evolution under visible light irradiation. Most solid solutions showed better activities than the single Cu3MS4 (M=V, Nb, Ta). Cu3MS4 (M=V, Nb), Cu3Nb1-xVxS4, and Cu3Ta1-xVxS4 also functioned as a photoelectrode and gave cathodic photocurrents under visible light irradiation, indicating a p-type semiconductor character. Cu3Nb0.9V0.1S4 showed the best photocatalytic and photoelectrochemical performances. When Ru-loaded Cu3Nb0.9V0.1S4 was used as a photocathode with a CoOx-loaded BiVO4 photoanode, photoelectrochemical water splitting proceeded under simulated sunlight irradiation without an external bias.
关键词： Energy conversion,Water splitting,Heterogeneous catalysis,Photocatalysis
更新于2025-11-19 16:51:07
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A direct one-step synthesis of ultrathin g-C3N4 nanosheets from thiourea for boosting solar photocatalytic H2 evolution
摘要： Two-dimensional (2D) graphitic carbon nitride (g-C3N4) nanosheets, as the promising photocatalyst with fascinating properties, have become a 'rising star' in the field of photocatalysis. Although g-C3N4 nanosheets exfoliated from the bulk g-C3N4 powders are extensively emerged, developing a simple synthetic approach is still full of challenge. To this end, here we report a direct polymerization strategy to fabricate the ultrathin g-C3N4 nanosheets, that is only heating treatment of thiourea in air without addition of any template. The photocatalytic activities of as-prepared samples were evaluated by photoreduction of water to hydrogen (H2) using triethanolamine as sacrificial agent and Pt as co-catalyst under visible-light irradiation (λ > 420 nm). As a result, our few-layered g-C3N4 nanosheets with an average thickness of 3.5 nm exhibit a superior visible-light photocatalytic H2 evolution rate (HER) of 1391 μmol g?1 h?1 and a remarkable apparent quantum efficiency of 6.6% at 420 nm. Eventually, the HER of as-fabricated ultrathin g-C3N4 nanosheets is not only much higher than the dicyandiamide-derived g-C3N4 or melamine-derived g-C3N4, but also greater than the thermal-oxidation etched g-C3N4 nanosheets under the same condition.
关键词： g-C3N4 nanosheets,Template-free polymerization,Solar energy conversion,2D materials,Photocatalysis,One-step synthesis
更新于2025-11-14 17:03:37
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Unravelling the effect of charge dynamics at the plasmonic metal/semiconductor interface for CO2 photoreduction
摘要： Sunlight plays a critical role in the development of emerging sustainable energy conversion and storage technologies. Light-induced CO2 reduction by artificial photosynthesis is one of the cornerstones to produce renewable fuels and environmentally friendly chemicals. Interface interactions between plasmonic metal nanoparticles and semiconductors exhibit improved photoactivities under a wide range of the solar spectrum. However, the photo-induced charge transfer processes and their influence on photocatalysis with these materials are still under debate, mainly due to the complexity of the involved routes occurring at different timescales. Here, we use a combination of advanced in situ and time-resolved spectroscopies covering different timescales, combined with theoretical calculations, to unravel the overall mechanism of photocatalytic CO2 reduction by Ag/TiO2 catalysts. Our findings provide evidence of the key factors determining the enhancement of photoactivity under ultraviolet and visible irradiation, which have important implications for the design of solar energy conversion materials.
关键词： Ag/TiO2 catalysts,photocatalysis,plasmonic metal nanoparticles,sustainable energy,solar energy conversion,artificial photosynthesis
更新于2025-10-22 19:40:53
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Edge/Defect-rich, Metallic, and Oxygen-heteroatom-doped WS2 Superstructure with Superior Electrocatalytic Performance for Green Solar Energy Conversion
摘要： Two-dimensional tungsten sulfide is widely applied in electrocatalysis field. However, WS2 possesses catalytic active sites located at the layer edge and an inert surface for catalysis. Therefore, increasing the exposure of active sites at the edge and effectively activating the inert sites on the surface is important challenges. Here, we synthesize edge/defect-rich and oxygen-heteroatom-doped WS2 (ED-O-WS2) superstructure. The power-conversion efficiency (PCE) of dye-sensitized solar cells (DSCs) based on ED-O-WS2 counter electrode reach 10.36% (under 1 Sun, AM 1.5, 100 mW cm?2) and 11.19% (under 40 mW cm?2). These values are, to our knowledge, the highest reported efficiency for DSCs based on Pt-free counter electrodes in I3-/I- electrolytes. Analysis of micro-nano structure and electrocatalytic mechanism indicate that ED-O-WS2 exhibit metallic properties in the electrolyte, and that rich edge/defect and oxygen doping in ED-O-WS2 play an important role in improving the catalytic activity of WS2. Moreover, ED-O-WS2 displays better catalytic reversibility for I3-/I- electrolytes than that of noble metal Pt.
关键词： WS2,green solar energy conversion,dye-sensitized solar cells,counter electrode
更新于2025-09-23 15:23:52
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Surface-Immobilized Conjugated Polymers Incorporating Rhenium Bipyridine Motifs for Electrocatalytic and Photocatalytic CO <sub/>2</sub> Reduction
摘要： The solar-driven conversion of CO2 to value-added products provides a promising route for solar energy storage and atmospheric CO2 remediation. In this report, a variety of supporting electrode materials were successfully modified with a [2,2′-bipyridine]-5,5′-bis(diazonium) rhenium complex through a surface-localized electropolymerization method. Physical characterization of the resulting multilayer films confirms that the coordination environments of the rhenium bipyridine tricarbonyl sites are preserved upon immobilization and that the polymerized catalyst moieties exhibit long-range structural order with uniform film growth. UV?vis studies reveal additional absorption bands in the visible region for the polymeric films that are not present in the analogous rhenium bipyridine complexes. Electrochemical studies with modified graphite rod electrodes show that the electrocatalytic activity of these films increases with catalyst loading up to an optimal value, beyond which electron and mass transport through the material become rate-limiting. Electrocatalytic studies performed at ?2.25 V vs Fc/Fc+ for 2 h reveal CO production with faradaic efficiencies and turnover numbers up to 99% and 3606, respectively. Photocatalytic studies of the modified TiO2 devices demonstrate enhanced activity at low catalyst loadings, with turnover numbers up to 70 during 5 h of irradiation.
关键词： metallopolymers,surface modification,photocatalysis,rhenium bipyridine,solar energy conversion,electrocatalysis
更新于2025-09-23 15:23:52
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Porous WO3 monolith-based photoanodes for high-efficient photoelectrochemical water splitting
摘要： We report a successful fabrication of low-cost, high-efficient, structurally-rigid, porous WO3 photoelectrochemical (PEC) catalysts using polystyrene as the template by a sol-gel method and a high-temperature annealing treatment. The scanning electron microscopy and Brunauer-Emmett-Teller surface analysis results indicate that such WO3 monoliths possess a porous structure and a large specific surface area, which can supply lots of photogenerated charge transfer pathways as well as more surface PEC active sites. Compared with a commercially available WO3, our highly porous WO3 PEC catalysts show an excellent PEC water splitting activity. Particularly, the porous WO3 photoanodes calcinated in the presence of oxygen atmosphere at 450 °C for 7 h show the best PEC performance exhibiting the photocurrent density of 0.97 mA/cm2 at 1.23 V versus reversible the hydrogen electrode and the incident photon-to-current conversion efficiency up to 48.9% at 420 nm in 0.5 M Na2SO4 electrolyte under AM 1.5 G irradiation. Such excellent PEC performance is due to the high porosity of the WO3, promoting the fast transfer and the separation rate of photogenerated carriers during the PEC water splitting process.
关键词： Water splitting,Porous structures,Energy conversion,WO3,Photoanode
更新于2025-09-23 15:23:52
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Atomically Precise Bimetallic Nanoclusters as Photosensitizers in Photoelectrochemical Cells
摘要： The atomically precise bimetallic nanocluster, Au24Ag20(PhCC)20(SPy)4Cl2 (1), is for the first time employed as a stable photosensitizer for photoelectrochemical applications. The sensitization of TiO2 nanotube arrays (TNA) with 1 greatly enhances the light harvest ability of the composite, as 1 shows high molar-extinction-coefficient in the UV-Vis region. Compared to a more standard Au25(SG)18 -TNA (2-TNA, SG: Glutathione), 1-TNA shows a much better stability under illumination both in neutral and basic conditions. The precise composition of the photosensitizers enables a direct comparison of the sensitization ability between 1 and 2. With the same cluster loading, the photocurrent produced by 1-TNA is 15 times larger than 2-TNA. The superior performance of 1-TNA over 2-TNA is attributed not only to the higher light absorption ability of 1, but also to the higher charge-separation efficiency. Besides, a ligand effect on the stability of the photoelectrode and charge-transfer between the NCs and the semiconductor is revealed. Our work paves the way to study the role of metal nanoclusters as photosensitizers at the atomic level, which is essential for the design of better material for light energy conversion.
关键词： Energy Conversion,Bimetallic Nanoclusters,Photosensitizers,Nanostructured Materials,Photoelectrochemical Cells
更新于2025-09-23 15:23:52
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Generalized optimization method for energy conversion and storage efficiency of nanoscale flexible piezoelectric energy harvesters
摘要： The energy conversion and storage efficiency was commonly ignored in experimental studies on nanoscale flexible piezoelectric energy harvesters (PEHs). In this study, we develop a generalized theoretical method to optimize the energy conversion and storage efficiencies of nanoscale flexible PEHs. The results are validated by comparisons with experimental measurements for various ambient excitations. A simple scaling law is established to reveal the intrinsic correlation between the efficiency of energy conversion/storage and various system parameters of the PEHs. For either the energy conversion or storage circuit, the output power density may be maximized by properly designing an intrinsic normalized parameter. Furthermore, we demonstrate that an independent optimization criterion is indispensable for standard storage circuits since including a storage module into the conversion circuit redefines the electromechanical behavior of the PEH system. The results may be used as guidelines for optimizing the energy conversion and storage efficiencies of nanoscale flexible PEHs that have promising applications in harvesting biomechanical energies.
关键词： Scaling law,Optimization,Nanoscale flexible piezoelectric energy harvesters,Energy conversion,Energy storage
更新于2025-09-23 15:22:29
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A Hybrid MMC-Based Photovoltaic and Battery Energy Storage System
摘要： This paper proposes a new configuration and its control strategy for a modular multilevel converter (MMC)-based photovoltaic (PV)-battery energy storage (BES) system. In the MMC-based PV-BES system, each PV submodule is interfaced from its dc side with multiple PV generators using isolated dual active bridge (DAB) dc-dc converters. One BES system is embedded into each arm of the converter and is connected to the dc port of the associated BES submodule using multiple isolated DAB converters. The embedded BES systems are used to smooth the output power of the PV generators and limit the rate of change of the power delivered to the host grid. Moreover, they enable compensation of power mismatches between the arms and legs of the system by exchanging power with the arms of the converter. The paper then proposes a hybrid power mismatch elimination strategy using a combination of power exchange with the arms of the converter and internal power flow control of the MMC. The proposed hybrid power mismatch elimination strategy employs BES systems and differential currents to compensate power mismatches and transfer power between the arms and legs of the converter, respectively. The effectiveness of the proposed power smoothing technique using the embedded BES systems and hybrid power mismatch elimination strategy is demonstrated using time-domain simulations conducted on a switched model of the PV-BES system in PSCAD/EMTDC software environment.
关键词： control,modular multilevel converter,power electronics,battery energy storage,photovoltaic,power mismatch,Differential current,energy conversion,integration
更新于2025-09-23 15:22:29