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Enhanced Charge Separation in g-C3N4 – BiOI Heterostructures for Visible Light Driven Photoelectrochemical Water Splitting
摘要： Heterojunctions of the low bandgap semiconductor bismuth oxyiodide (BiOI) with bulk multilayered graphitic carbon nitride (g-C3N4) and few layered graphitic carbon nitride sheets (g-C3N4-S) are synthesized and investigated as an active photoanode material for sunlight driven water splitting. HR-TEM and elemental mapping reveals formation of a unique heterostructure between BiOI platelets and the carbon nitride (g-C3N4 and g-C3N4-S) network that consisted of dendritic BiOI nanoplates surrounded by g-C3N4 sheets. The presence of BiOI in g-C3N4-S/BiOI and g-C3N4-S/BiOI nanocomposites extends the visible light absorption profile from 500 nm up to 650 nm. Due to excellent charge separation in g-C3N4/BiOI and g-C3N4-S/BiOI, evident from quenching of the carbon nitride photoluminescence (PL) and a decrease in the PL lifetime, a significant increase in photoelectrochemical performance is observed for both types of g-C3N4-BiOI heterojunctions. In comparison to heterojunctions of bulk g-C3N4 with BiOI, the nancomposite consisting of few layered sheets of g-C3N4 and BiOI exhibits higher photocurrent density due to lower recombination in few layered sheets. A synergistic trap passivation and charge separation is found to occur in the g-C3N4-S/BiOI nanocomposite heterostructure which results in a higher photocurrent and a lower charge transfer resistance.
关键词： visible light driven photocatalysis,earth abundant semiconductor heterostructures,Graphenic semiconductors,photoelectrochemistry
更新于2025-11-21 11:01:37
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Synthesis of Ruthenium Tris-Diimine Photosensitizers Substituted by Four Methylphosphonate Anchoring Groups for Dye-Sensitized Photoelectrochemical Cell Applications
摘要： The design and synthesis of ruthenium tris-diimine photosensitizers appropriately functionalized to be (i) anchored onto transparent conductive oxides (TCO) and (ii) covalently coupled with a water-splitting catalyst represents an important target for solar fuel production in dye-sensitized photoelectrochemical cells (DS-PECs). In this study, two different synthetic routes to prepare heteroleptic [Ru(4,4′-(CH2PO3Et2)2-bpy)2(N^N)](PF6)2 complexes are evaluated, the scope and limitations of the organometallic pathway involving half-sandwich η6-arene ruthenium complexes as synthetic intermediates being especially studied. The spectroscopic and electrochemical characterization of a series of novel structures varying by the nature of the third diimine N^N ligand is reported.
关键词： Photoelectrochemistry,Photosensitizers,Anchoring groups,Ruthenium
更新于2025-11-19 16:56:35
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Improving Photovoltaic and Enzymatic-Sensing Performance by Coupling Core-Shell Au Nanorod@TiO2 Heterostructure with Bioinspired L-DOPA Polymer
摘要： The photoelectrochemistry (PEC) performance of TiO2 is somewhat limited by its wide band gap and low quantum efficiency, and the innovation of its composite materials provides a promising solution for an improved performance. Herein, a composite of an Au nanorod@TiO2 core-shell nanostructure (AuNR@TiO2) and a melanin-like L-DOPA polymer (PD) is designed and prepared, where the outer-layer PD tethered by the TiO2-hydroxyl complexation and the AuNR core can intensify the long-wavelength light harvesting, and the AuNR@TiO2 core-shell structure can strengthen the hot-electron transfer to TiO2. The photocurrent of the PD/AuNR@TiO2 is 8.4-fold improved versus that of commercial TiO2, and the maximum incident photon-to-electron conversion efficiency reaches 65% in the UV-visible-near-infrared region. In addition, the novel PD/AuNR@TiO2 photocatalyst possesses the advantages of good biocompatibility and stability, which can act as a versatile PEC biosensing platform for providing biocompatible environment and improving detection sensitivity. Herein, a PEC enzymatic biosensor of glucose is developed on the basis of the immobilization of dual enzyme (glucose oxidase (GOx) and horseradish peroxidase (HRP)) in PD and the signalling strategy of biocatalytic precipitation. In phosphate buffer containing glucose and 4-chloro-1-naphthol, the HRP-catalyzed oxidation of 4-chloro-1-naphthol by GOx-generated H2O2 can form a precipitate on the electrode, by which the decrement of photocurrent intensity is proportional to the common logarithm of glucose concentration. The linear detection range is from 0.05 μM to 10.0 mM glucose, with a limit of detection of 0.01 μM (S/N=3). Glucose in some human serum samples is analyzed with satisfactory results.
关键词： Au nanorod@TiO2 core-shell heterostructure,biocatalytic precipitation,bioinspired L-DOPA polymer,photoelectrochemistry,enzymatic sensing of glucose
更新于2025-11-14 17:04:02
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A novel photoelectrochemical biosensor for the sensitive detection of dual microRNAs using molybdenum carbide nanotubes as nanocarriers and energy transfer between CQDs and AuNPs
摘要： Herein, a novel photoelectrochemical (PEC) biosensor was developed for the ultrasensitive detection of dual microRNAs (miRNAs), with the detection being based on energy transfer (ET) between carbon quantum dots (CQDs) and gold nanoparticles (AuNPs). The PEC platform consisted of a CQDs@Mo2C nanotube modified ITO electrode. Two hairpin probes (H1 and H2) carrying the Au NPs were used “switch off” and “switch on” the PEC signal of the CQDs, with a close approach of the tagged AuNPs to the CQDs quenching the PEC signal. The introduction of different miRNAs (miRNA-159b and miRNA-166a) altered the interparticle distance between the AuNPs and CQDs, thereby affecting the intensity of the PEC response. This approach allowed the highly sensitive detection of both miRNA-159b and miRNA-166a. The linear range of the biosensor for miRNA-159b and miRNA-166a detection were 0.5–5000 fM, with low detection limits of 0.15 fM and 0.21 fM, respectively. To our knowledge, this is the first reported CQDs-based ET biosensor for the PEC detection of dual miRNAs. Results suggest that this approach offers a promising platform for the ultrasensitive detection of multiple miRNAs.
关键词： MicroRNA detection,AuNPs,Photoelectrochemistry,Energy transfer,CQDs@Mo2C
更新于2025-11-14 17:03:37
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Enzyme-free “on-off-on” photoelectrochemical biosensor based on cascaded quadratic amplification strategy for miRNA 141 detection
摘要： MicroRNAs (miRNAs) assay is of great significance for early diagnosis of diseases, so an enzyme-free “on-off-on” PEC biosensor has been developed for sensitive miRNA 141 determination. Manganese-doped cadmium sulfide coupled with zinc sulfide quantum dots (Mn:CdS@ZnS QDs) and manganese porphyrin (MnPP) have been used as photoelectric material and photosensitizer, respectively. And a high photocurrent of approximately 70.0 μA has been obtained. Cascaded quadratic amplification strategy has been applied in the system. Mn:CdS@ZnS QDs was characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX). Photoelectrochemical and electrochemical technologies were used to monitor the fabrication process of the biosensor. The sensing platform exhibits recommendable stability and good selectivity, miRNA 141 can be accurately quantified with a linear range of 1.00 × 10-14 to 1.00 × 10-8 mol·L-1 and the detection limit of 3.30 fmol·L-1. This method provides promising potential to explore sensitive detection models for various biological molecules.
关键词： Hybridization chain reaction,Catalytic hairpin assembly,Manganese-doped cadmium sulfide coupled with zinc sulfide quantum dots,MiRNA 141,Photoelectrochemistry,On-off-on
更新于2025-11-14 17:03:37
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Mo/CIGS/CdS Structures by E‐ALD
摘要： The chalcopyrite CuIn(1-x)GaxSe2 (CIGS) thin films and their cadmium sulfide (CdS) window layer structures (CIGS/CdS) were grown on Mo foil substrate in layer-by-layer fashion by electrochemical atomic layer deposition (E-ALD) and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and photoelectrochemical (PEC) activity. XRD shows distinct pattern changes from chalcopyrite to chalcopyrite plus CdS structures upon adding E-ALD CdS layer to CIGS layers on Mo substrate. SEM shows that uniform and homogeneously distributed nanoparticles of CdS formed on top of CIGS layers, and EDS shows the successful preparation of CIGS/CdS structures with good atomic ratios in each layer. PEC performance reveals that bare CIGS films were of p-type conductivity but that CIGS/CdS structures n-type with p-type response near null.
关键词： Photoelectrochemistry,CuIn(1-x)GaxSe2/cadmium sulfide,Chalcopyrites,Electrochemical atomic layer deposition
更新于2025-11-14 14:48:53
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Quantifying Photocurrent Loss of a Single Particle–Particle Interface in Nanostructured Photoelectrodes
摘要： Particle?particle interfaces are ubiquitous in nanostructured photoelectrodes and photovoltaics, which are important devices for solar energy conversion. These interfaces are expected to cause performance losses in these devices, but how much loss they would incur is poorly defined. Here we use a subparticle photoelectrochemical microscopy approach in combination with specific photocurrent measurement electrode configurations to quantify the current losses from single particle?particle interfaces formed between individual TiO2 nanorods operating as photoanodes in aqueous electrolytes. We find that a single interface leads to ～20% photocurrent loss (i.e., ～80% retention of the original current). Such quantitative, first-of-its-kind, information provides a metric for guiding the optimization and design of nanostructured photoelectrodes and photovoltaics.
关键词： single nanorod photoelectrodes,interface losses,Subparticle photoelectrochemistry
更新于2025-09-23 15:23:52
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Challenges in semiconductor single entity photoelectrochemistry
摘要： It is challenging to study the single semiconductor (SC) nanocrystal electrochemistry and photoelectrochemistry. The photocatalytic process that results from the electron-hole pair formed within a nanoparticle (NP) like the oxidation of methanol and iodide allow the detection of discrete current transient events assigned to single entities. Photocatalytic current amplification allows detection of collisions between the semiconductor NPs and the ultramicroelectrode (UME) that produce current transient. Staircase responses and blips in the i vs. t response indicate that irreversible and reversible NP/electrode interactions result depending on the experimental conditions. Dye sensitization increases the photocurrent magnitude of ZnO and TiO2 with respect to bare TiO2 NPs. The microelectrodes used are Pt, TiO2/Pt, TiO2/Au and F-doped SnO2 (FTO).
关键词： semiconductor,photoelectrochemistry,ultramicroelectrode,nanoparticle,dye sensitization,single entity
更新于2025-09-23 15:23:52
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Significant enhancement of photoactivity in one-dimensional TiO2 nanorods modified by S-, N-, O-doped carbon nanosheets
摘要： Titanium dioxide (TiO2) represents one of the most active photocatalysts among metal oxides for the degradation of pollutants and for solar water splitting to produce hydrogen. The most critical drawbacks hindering its broad practical use are the absorption majorly in the UV part of solar spectrum and slow charge dynamics. Combination of TiO2 with a suitable partner in a hybrid nanostructure can effectively address these drawbacks. Here we report a novel nanocomposite system based on one-dimensional TiO2 nanorods wrapped with a sulfur-, nitrogen-, and oxygen-doped carbon (SNOC) nanosheets. The SNOC nanosheets are synthesized by a cost-effective and facile route using eco-friendly carrageenan as a sulfur, oxygen, and carbon source and urea as a nitrogen source. Silica was used as the templating agent that leads to large surface area materials after its removal at the end of the synthesis. Therefore, the synthesized material exhibits superior photocatalytic performance for decoloring representative Rhodamine B (RhB) under visible light irradiation. SNOC shows the apparent rate constant of 7.6 × 10–3 min–1, which is almost 3 times higher than that of a SNOC material without using silica (2.8 × 10–3 min–1). This performance of doped carbon material can be assigned to the effect of large surface area and effective visible light adsorption. The TiO2 NRs / SNOC nanocomposite was investigated for photoelectrochemical water splitting showing much higher photocurrent densities (0.85 mA cm–2) than pure TiO2 nanorod arrays (0.35 mA cm–2), which was due to significant improvement in the charge transfer dynamics and co-catalytic effect of SNOC. All the materials prepared were evaluated on the basis of physical properties such as crystalline structure, optical absorption, surface topography, and electronic properties.
关键词： Water splitting,Photoelectrochemistry,Photocatalysis,Heterojunction,TiO2 nanorods,S, N, O-doped mesoporous carbon
更新于2025-09-23 15:23:52
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Photocathodic hydrogen evolution from catalysed nanoparticle films prepared from stable aqueous dispersions of P3HT and PCBM
摘要： Photo-assisted hydrogen evolution is achieved on photocathodes comprising of nanoparticles of poly(3-hexylthiophene) (npP3HT) and nanoparticles of phenyl-C61-butyric acid methyl ester (npPCBM) onto which ultra-low loadings of Pt nanoparticles are deposited. The nanoparticles, npP3HT and npPCBM, are prepared individually via miniemulsion using surfactants of opposite head group polarity. Aqueous dispersions of npP3HT:npPCBM, devoid of organic solvent, are cast conformally onto ITO-coated glass to yield water-insoluble bulk-heterojunction films. Pt is deposited photoelectrochemically onto ITO/npP3HT:npPCBM photocathodes and found to nucleate preferentially on PCBM nanoparticles. ITO/npP3HT:npPCBM/Pt photocathodes produce 65 μA/cm2 photocurrent under 100 mW/cm2 of visible light at 0.0 VSHE and liberate H2 gas. The photocurrents observed for electrodes prepared using npP3HT:npPCBM are twice as large, and the onset potential is ～0.4 V more positive than analogous photocathodes cast from nanoparticles each comprising an intimate blend of P3HT and PCBM. These are encouraging results for large scale synthesis of organic photoelectrochemical devices, given the simplicity of the photoelectrode, i.e., prepared from aqueous solutions and devoid of vacuum-deposited films such as charge transport layers and protective films.
关键词： Polymer nanoparticle,Photoelectrochemistry,P3HT: PCBM bulk-heterojunction,Solar hydrogen generation,Organic semiconductor,Mini-Emulsion
更新于2025-09-23 15:23:52