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Photo-induced generation of size controlled Au nanoparticles on pure siliceous ordered mesoporous silica for catalytic applications
摘要： A versatile in situ photochemical reduction approach was used to generate a composite of gold nanoparticles and pure siliceous SBA-15 silica support with regular mesopores. The mesoporous silica support was first synthesized and, after calcination, was suspended in a solution of gold bromide (EtOH or H2O) containing a free radical generator activated by UV irradiation and used for the photochemical reduction of gold precursor. The influence of gold precursor concentration, light intensity and nature of the solvents on the formation and properties of gold nanoparticles (size, dispersion, stability) on the mesoporous SBA-15 support have been studied with the aim of optimizing the dispersion of the gold nanoparticles in the mesoporous network and their chemical stability. The catalytic activity of the resulting AuNPs@SBA-15 nanocomposite was successfully evaluated for the oxidation of benzyl alcohol reaction in liquid-phase.
关键词： Benzyl alcohol,Photoreduction,Gold nanoparticles,Mesoporous silica,SBA-15,Oxidation
更新于2025-09-12 10:27:22
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Efficiency and Stability Enhancement of Fully Ambient Air Processed Perovskite Solar Cells Using TiO <sub/>2</sub> Paste with Tunable Pore Structure
摘要： Crystallization and nucleation of the perovskite layer in the mesoscopic perovskite solar cells (PSCs) depend on the nucleation sites of the electron transport layer (ETL). The porosity optimization of TiO2 film as an efficient ETL plays an important role in the performance improvement of PSCs. In the present study, nontoxic carbon spheres synthesized with uniform morphology and controllable size under hydrothermal conditions and used as a template to generate the tunable porous TiO2 films. Furthermore, the effect of porosity modification of TiO2 on the formation of perovskite films with large grain size is studied in an ambient atmosphere with humidity higher than 50%. The best TiO2 film is produced with carbon spheres 8 wt% (C8), which results in the formation of a pinhole-free, and compact-packed perovskite layer. The fully air processed PSC device with the ETL made of C8 film exhibits an efficiency of 16.66% with reduced hysteresis, which is much superior in performance compared to the standard cell (11.72%). It is believed that this porosity optimization of TiO2 layer is a simple practical strategy for improved stability of fully air processed efficient perovskite solar cells and usable for the fabrication of reproducible compact perovskite layers in uncontrolled laboratories.
关键词： porosity,AP-VASP,carbon sphere,mesoporous TiO2,perovskite solar cells
更新于2025-09-12 10:27:22
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Ionically Modified Cellulose Nanocrystal Self-Assembled Films with a Mesoporous Twisted Superstructure: Polarizability and Application in Ion-Gated Transistors
摘要： Mesoporous structures made of cellulose nanocrystals (CNCs) and their self-assembly into films is of great interest not only due to their abundancy and sustainability but also due to their ease of chemical modification and nanoscale bio mimicry capabilities. However, their implementation in (opto)electronic devices requires further understanding on how these self-assembled twisted mesoporous superstructures respond to electrical stimulus. In this regard, this work focusses in the infiltration with three distinct alkali ions (Li+, Na+ and K+) to yield films with improved electrochemical response when compared to pristine ones, while preserving their photonic character. Electrochemical characterization shows capacitances of up to 2.5 μF cm-2 allowing for their integration as solid-state gate electrolytes in amorphous indium-gallium-zinc-oxide transistors, resulting in low operating voltages (< 2 V), On/Off ratios of up to 6 orders of magnitude and high saturation mobilities >10 cm2 V-1 s-1. Devices fabricated on Na+ and K+ infiltrated CNC films present the best characteristics, indicating pure capacitive charging of the semiconductor. The insights presented here contribute to applications in solid-state ionics in mesoporous structures or the combination of optically active electrolytes capable of providing unique functionalities in ion-gated transistors and circuitry.
关键词： Self-assembly,Mesoporous Structures,Cellulose Nanocrystals,Ion Gated Transistors,Photonics
更新于2025-09-12 10:27:22
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Enhanced Lifetime and Photostability with Low‐temperature Mesoporous ZnTiO3/Compact SnO2 Electrodes in Perovskite Solar Cells
摘要： Perovskite solar cells (PSC) which have exceeded power conversion efficiencies (PCEs) of 25% are mainly demonstrated by using SnO2 or TiO2 as electron-transporting layers (ETLs). However, high-performance planar PSCs need precise process, which is difficult for large-scale production. Mesoporous structure shows better operability but with high-temperature process. Besides, as the most used mesoporous materials, the strong photocatalytic effect of TiO2 significantly limits the practical stability of PSCs under illumination (including ultraviolet light). Here we propose Zinc Titanate (ZnTiO3, ZTO) as mesoporous ETLs due to its weak photo-effect, excellent carrier extraction and transfer properties. Uniform mesoporous films were obtained by spinning coating the ZTO ink and annealed below 150°C. Photovoltaic devices based on Cs0.05FA0.81MA0.14PbI2.55Br0.45 perovskite sandwiched between SnO2-mesorporous ZTO electrode and Spiro-OMeTAD layer achieved the PCE of 20.5%. The PSCs retained more than 95% of their original efficiency after 100 days lifetime test without being encapsulated. Additionally, the PSCs retained over 95% of the initial performance when subjected at the maximum power point voltage for 120 h under AM 1.5G illumination (100 mW cm-2), demonstrating superior working stability. The application of ZTO provides a better choice for ETLs of PSCs. Moreover, the low temperature deposition method of inorganic ETL furnishes a way of low power consumption, large-scale and flexible preparation of PSCs.
关键词： perovskite solar cell,mesoporous ETL,photostability,ZTO,low-temperature
更新于2025-09-11 14:15:04
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Mesoporous Tungsten Trioxide Photoanodes Modified with Nitrogen-Doped Carbon Quantum Dots for Enhanced Oxygen Evolution Photo-Reaction
摘要： Nanostructured photoanodes are attractive materials for hydrogen production via water photo-electrolysis process. This study focused on the incorporation of carbon quantum dots doped with nitrogen as a photosensitizer into mesoporous tungsten trioxide photoanodes (N-CQD/meso-WO3) using a surfactant self-assembly template approach. The crystal structure, composition, and morphology of pure and N-CQD- modi?ed mesoporous WO3 photoanodes were investigated using scanning electron and transmission microscopy, X-ray di?raction, and X-ray photoelectron spectroscopy. Due to their high surface area, enhanced optical absorption, and charge-carrier separation and transfer, the resulting N-CQD/meso-WO3 photoanodes exhibited a signi?cantly enhanced photocurrent density of 1.45 mA cm?2 at 1.23 V vs. RHE under AM 1.5 G illumination in 0.5 M Na2SO4 without any co-catalysts or sacri?cial reagent, which was about 2.23 times greater than its corresponding pure meso-WO3. Moreover, the oxygen evolution onset potential of the N-CQD/meso-WO3 photoanodes exhibited a negative shift of 95 mV, signifying that both the charge-carrier separation and transfer processes were promoted.
关键词： tungsten,dots,trioxide,photo-electrochemical,mesoporous,quantum,carbon,water splitting
更新于2025-09-11 14:15:04
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Spin-coated copper(I) thiocyanate as a hole transport layer for perovskite solar cells
摘要： Application of a low-cost and efficient p-type inorganic hole-transporting material, copper thiocyanate (CuSCN), on mesoporous n-i-p-configurated perovskite-based devices was conducted in this study. Diethylsulfide was chosen for the preparation of precursor solution in order to deposit CuSCN layer on perovskite without degrading it. Topographical, elemental, and electrical characterizations of spin-coated CuSCN layers were performed using XRD, AFM, SEM, XPS, UPS, and UV-Vis studies. A power conversion efficiency exceeding 11.02% with an open-circuit voltage of 0.83 V was succeeded in the perovskite solar cells under full sun illumination. Low-temperature solution process used for the deposition of CuSCN and a fast solvent removal method allowed the creation of compact, highly conformal CuSCN layers that facilitate rapid carrier extraction and collection. The differences in series and recombination resistances for CuSCN-free and CuSCN-containing cells were also determined using impedance spectroscopy (IS) analysis. Moreover, the effect of TiO2 layer thickness on the cell performance was studied where these TiO2 layers were used not only for electron extraction and transportation, but also as hole blocking layer in perovskite solar cells. The impedance spectroscopy results were also consistent with the differently configurated cell performances. This work shows a well-defined n-i-p perovskite cell with optimized layers which utilize low-cost and abundant materials for photovoltaic applications.
关键词： Hole transport material,Perovskite solar cells,N-i-p mesoporous structure,Copper thiocyanide thin film
更新于2025-09-11 14:15:04
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Detection of IL-8 in human serum using surface-enhanced Raman scattering coupled with highly-branched gold nanoparticles and gold nanocages
摘要： Mesoporous materials are ideal carriers for guest molecules and they have been widely used in analytical science. The unique mesoporous structure provides special properties including large specific surface area, tunable pore size, and excellent pore connectivity. The structural properties of mesoporous materials have been largely made use of to improve the performance of analytical methods. For instance, the large specific surface area of mesoporous materials can provide abundant active sites and increase the probability of contact between analytes and active sites to produce stronger signals, thus leading to the improvement of detection sensitivity. The connections between analytical performances and the structural properties of mesoporous materials have not been discussed previously. Understanding the "structure–performance relationship" is highly important for the development of analytical methods with excellent performance based on mesoporous materials. In this review, we discuss the structural properties of mesoporous materials that can be optimized to improve the analytical performance. The discussion is divided into five sections according to the analytical performances: (i) selectivity-related structural properties, (ii) sensitivity-related structural properties, (iii) response time-related structural properties, (iv) stability-related structural properties, and (v) recovery time-related structural properties.
关键词： analytical science,stability,recovery time,response time,structure–performance relationships,selectivity,sensitivity,mesoporous materials
更新于2025-09-11 14:15:04
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<i>In situ</i> fabrication of a direct <i>Z</i> -scheme photocatalyst by immobilizing CdS quantum dots in the channels of graphene-hybridized and supported mesoporous titanium nanocrystals for high photocatalytic performance under visible light
摘要： We report the considerable advantages of direct Z-scheme photocatalysts by immobilizing high-quality CdS quantum dots (QDs) in the channels of graphene-hybridized and supported mesoporous titania (GMT) nanocrystals (CdS@GMT/GR) under facile hydrothermal conditions. The photocatalysts have been characterized by XRD, PL, XPS, SEM, DRS, TEM, EIS, and N2 adsorption. CdS QDs primarily serve as photosensitizers with a unique pore-embedded structure for the e?ective utilization of the light source. This direct Z-scheme CdS@GMT/GR exhibits higher photocatalytic activity than CdS/GR, GMT/GR, or CdS@MT. In addition, the rate constant of CdS@GMT/GR-2 is approximately twice the sum of those of CdS@MT and GMT/GR, because GR played the role of hole-transporting and collection layer as well as the hybridization level formation in terms of hybridizing MT and serving as a support. Therefore, the GR content tunes the energy band, a?ects the surface area, and controls the interfacial hole transfer and collection rate of the direct Z-scheme system. Furthermore, CdS@GMT/GR retains its high performance in repeated photocatalytic processes. This can be attributed to the fact that GR prevents QDs from photocorrosion by means of the hole-transporting and collection e?ect. A possible reaction mechanism is proposed. This work provides a promising strategy for the construction of highly e?cient visible-light-driven photocatalysts to reduce the growing menace of environmental pollution.
关键词： environmental pollution,visible-light-driven photocatalysts,graphene-hybridized mesoporous titania,direct Z-scheme photocatalysts,CdS quantum dots
更新于2025-09-11 14:15:04
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Effects of Organic Cations on Carrier Transport at the Interface between Perovskites and Electron Transport Layers in (FA,MA)SnI <sub/>3</sub> Solar Cells
摘要： Charge extraction at carrier transport layers adjacent to perovskites is crucial for the optimization of perovskite solar cells. In particular, Sn–perovskites with no lead elements are known to struggle from charge extraction. Here, we report the effects of organic ligands like FA and MA (FA = HC(NH2)2+; MA = CH3NH3+) on charge separation at the interface between electron transport layers and perovskites. TiO2 mesoporous covering the tin-perovskites show significant changes in electronic structure and built–in potentials according to the ratio of FA to MA. Through a local probe with potential and current mapping, charge transport has been intensively examined. The best cell in this study is obtained as 5.37% at FA : MA = 3 : 1 with only iodine at the halide sites. Even though the value itself is not comparable with lead halides but it could pave a new direction to improve lead–free perovskite solar cells.
关键词： perovskite solar cells,tin perovskites,TiO2 mesoporous,charge extraction,organic cations
更新于2025-09-11 14:15:04
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Dopant-Free Squaraine-Based Polymeric Hole-Transporting Materials with Comprehensive Passivation Effects for Efficient All-Inorganic Perovskite Solar Cells
摘要： Quantum-dot (QD) white light-emitting diodes (LEDs) are promising for illumination and display applications due to their excellent color quality. Although they have a high quantum yield close to unity, the reabsorption of QD light leads to high conversion loss, significantly reducing the luminous efficacy and stability of QD white LEDs. In this report, SBA-15 mesoporous particles (MPs) with two-dimensional hexagonal pore structures (2D-HPS) are utilized to largely enhance the luminous efficacy and color-conversion efficiency of QD white LEDs in excess of 50%. The reduction in conversion loss also helps QD white LEDs to achieve a lifetime 1.9 times longer than that of LEDs using QD-only composites at harsh aging conditions. Simulation and testing results suggest that the waveguide effect of 2D-HPS helps in reducing the reabsorption loss by constraining the QD light inside the wall of 2D-HPS, decreasing the probability of being captured by QDs inside the hole of 2D-HPS. As such, materials and mechanisms like SBA-15 MPs with 2D-HPS could provide a new path to improve the photon management of QD light, comprehensively enhancing the performances of QD white LEDs.
关键词： stability,two-dimensional hexagonal pore structure,reabsorption,luminous efficacy,SBA-15 mesoporous particle,quantum-dot white light-emitting diode
更新于2025-09-11 14:15:04