- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Semiconductor Photocatalysis - Materials, Mechanisms and Applications || Photocatalytic Removal of Organics over BiVO4-Based Photocatalysts
摘要： Organic compounds, such as organic dyes and phenols, are the main pollutants in wastewater. In the past years, a large number of studies on the fabrication and photocatalytic organics degradation of BiVO4 and its related materials have been reported in the literature. In this chapter, we shall focus on the advancements in the synthesis and photocatalytic applications of several kinds of BiVO4-based photocatalysts: (i) well-defined morphological BiVO4 photocatalysts, (ii) porous BiVO4 photocatalysts, (iii) heteroatom-doped BiVO4 photocatalysts, (iv) BiVO4-based heterojunction photocatalysts, and (v) supported BiVO4 photocatalysts. We shall discuss the structure–photocatalytic performance relationship of the materials and the involved photocatalytic degradation mechanisms. In addition, we also propose the research trends and technologies for practical applications of the BiVO4-based photocatalytic materials.
关键词： BiVO4-based heterojunction,well-defined morphology,heteroatom-doped BiVO4,supported BiVO4,porous BiVO4 photocatalyst
更新于2025-09-23 15:21:01
-
Determination of the Optimal Sensing Temperature in Pt/Ta2O5/MoO3 Schottky Contacted Nanobelt Straddling Heterojunction
摘要： Nanostructured Schottky barrier gas sensors have emerged as novel semiconductor devices with large surface areas and unique electronic characteristics. Although it is widely known that operating these gas sensors requires heating to an optimal temperature for the highest sensitivity, the fundamental mechanism that governs the temperature-dependent sensitivity has yet been well understood. In this work, we present new evidence to support that thermionic field emission (TFE) is the dominant transport mechanism for Schottky contacted nanostructured heterojunction gas sensors at their optimal sensing temperature. Through the fabrication and characterization of Pt/MoO3 Schottky contacts, and Pt/Ta2O5/MoO3 heterojunctions, we found a previously unreported connection between TFE transport and optimal gas sensing temperature. This connection enables the description of Schottky barrier gas sensing performance using transport theory, which is a major step towards systematic engineering of gas sensors with nanostructured high-k oxide layers.
关键词： nanobelt,Ta2O5,optimal sensing temperature,heterojunction,Schottky barrier,MoO3
更新于2025-09-23 15:21:01
-
Lithography-free and dopant-free back-contact silicon heterojunction solar cells with solution-processed TiO2 as the efficient electron selective layer
摘要： Lithography-free interdigitated back-contact silicon heterojunction (IBC-SHJ) solar cells with dopant-free metal oxides (TiO2 and MoOx) as the carriers selective transport layers were investigated. Spin-coating and hot-wire reactive-sublimation deposition together with low cost mask technology were used to fabricate the solar cells. Insertion of a SiOx layer with the thickness of about 2.4 nm between the intrinsic amorphous Si (a-Si:H(i)) passivation layer and the spin-coated TiO2 layer greatly improves the solar cell performance due to the enhanced field-effect passivation of the a-Si:H(i)/SiOx/TiO2 layer stack. Efficiency up to 20.24% was achieved on the lithography-free and dopant-free IBC-SHJ devices with a-Si:H(i)/SiOx/TiO2 layer stack as the electron selective transport layer, a-Si:H(i)/MoOx as the hole selective transport layer, and WOx as the antireflection layer. The novel IBC-SHJ solar cells show significant advantages in simplification of the technology and process compared with the IBC-SHJ devices whose back surface pattering and carrier selective layers relied on photolithography and plasma enhanced chemical vapor deposition (PECVD).
关键词： Heterojunction,Dopant-free,Back-contact,Lithography-free,Passivation
更新于2025-09-23 15:19:57
-
Laser firing in silicon heterojunction interdigitated back contact architecture for low contact resistance
摘要： This work reports a laser firing technique applied to completed silicon heterojunction interdigitated back contact solar cells in order to lower contact resistance. Previously, the implementation of a-Si:H(i) at the electron contact of polycrystalline silicon solar cells on glass substrates led to an increase in series resistance. The cell architecture with the current record efficiency of 14.2% (with illumination through glass) utilizes only an a-Si:H(nt) layer (cid:0) 2 of short circuit current density is lost due to electrical shading under the electron contact and 2–2.9 mA cm [1,2]. The goal of implementing an a-Si:H(i) layer and laser firing at this contact is to achieve low contact resistance at fired spots while preserving a-Si:H(i) passivation in unfired regions. After the laser firing, VOC was (cid:0) 2 loss in JSC. In the best retained, while up to 14% absolute increase in FF was obtained with a mere 0.2 mA cm (cid:0) 2 loss in JSC. Two laser sources were used to first performing cell, a 72.1% FF was achieved with a 0.7 mA cm ablate a part of the silver contact metal, and then to laser fire through the Si(n)/a-Si:H(i/nt)/ITO/Ag contact. (cid:0) 2 (355 nm, picosecond pulse duration) and The optimal laser fluence was found to be 1.1–0.5 J cm (cid:0) 2 (532 nm, nanosecond pulse duration), respectively. The upper limit on specific contact resistance 4.4–5.2 J cm in the laser fired spots was calculated to be 38 ? 20 mΩcm2 as a conservative estimate.
关键词： Liquid phase crystallized silicon,Passivation,Interdigitated back contact,Foreign substrates,Laser fired contacts,Silicon heterojunction
更新于2025-09-23 15:19:57
-
An efficient and robust exfoliated bentonite/Ag <sub/>3</sub> PO <sub/>4</sub> /AgBr plasmonic photocatalyst for degradation of parabens
摘要： Efficient visible-light-driven heterojunction photocatalysts have attracted broad interest owing to their promising adsorption and degradation performances in the removal of organic pollutants. In this study, a mesoporous exfoliated bentonite (EB)/Ag3PO4/AgBr (30%) photocatalyst was obtained by stripping and exfoliating bentonite as the support for loading Ag3PO4 and AgBr. The particle size ranges of Ag3PO4 and AgBr were about 10–30 nm and 5–10 nm, respectively. The exfoliated bentonite could greatly improve the dispersion and adsorption of Ag3PO4 and AgBr, and significantly enhance the stability of the material during paraben photodegradation. 0.2 g L?1 methylparaben (MPB) was completely decomposed over the EB/Ag3PO4/AgBr (30%) in 40 min under visible light irradiation. In addition, the photocatalytic activity of EB/Ag3PO4/AgBr (30%) remained at about 91% after five recycling runs manifesting that EB/Ag3PO4/AgBr (30%) possessed excellent stability. Radical quenching tests revealed that holes (h+) and hydroxyl radicals (?OH) were the major radicals. They attacked the side chain on the benzene ring of parabens, which were gradually oxidized to the intermediates, such as benzoic acid, 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, azelaic acid, and eventually became CO2 and H2O. The enhancement of photocatalytic activity and photo-stability could be ascribed to the stable structural characteristics, enlarged surface area, high absorption ability, and improved light absorption ability from loading Ag3PO4 onto EB. Meanwhile, the matched energy levels of Ag3PO4 and AgBr made the photoelectron–hole pairs separate and transfer effectively at the interfaces. As a result, the photocatalytic properties of EB/Ag3PO4/AgBr (30%) composites were enhanced.
关键词： heterojunction photocatalysts,exfoliated bentonite,Ag3PO4/AgBr,paraben photodegradation,visible-light-driven
更新于2025-09-23 15:19:57
-
Utility of copper oxide nanoparticles (CuO-NPs) as efficient electron donor material in bulk-heterojunction solar cells with enhanced power conversion efficiency
摘要： In the present work, we have endeavored the utilization of wet-chemically synthesized copper oxide nanoparticles (CuO-NPs) as the active layer in hybrid bulk heterojunction (BHJ) solar cells. The BHJs with CuO-NPs display significantly different physics from customary BHJs, and prove a noteworthy improvement in their performance. It is noted that with the addition of CuO-NPs, the morphology of the photoactive layer endures significant changes. Incorporating CuO-NPs is an additional paradigm for BHJs solar cells which enhances the photocurrent density from 9.43 mA/cm2 to 11.32 mA/cm2 and the external quantum efficiency as well. Also the power-conversion efficiency (PCE) improved from 2.85 % to 3.82 % without harming the open circuit voltage and the fill factor. The enhancement in PCE achieved here makes it worthy to design high-performance organic solar cells holding inorganic nanoparticles.
关键词： thin films,Bulk heterojunction,Solar cells,external quantum efficiency,Copper oxide nanoparticles,photo current density
更新于2025-09-23 15:19:57
-
Measurement and Theoretical Interpretation of Exciton Diffusion as a Function of Intermolecular Separation for Squaraines Targeted for Bulk Heterojunction Solar Cells
摘要： The efficiency of bulk heterojunction (BHJ) organic photovoltaic (OPV) devices depends significantly upon absorption of photons and the migration of the photogenerated excited state to the heterojunction interface between the electron donor and electron acceptor. Within anilino-squaraine, molecules known for their successful use in the active layer of OPV devices, electronic aggregation strongly influences the absorption spectrum, energy transfer (EnT), and exciton migration to this heterojunction interface. Therefore, the long-range transition dipole coupling and the relative populations of the associated excited states dictate the general effectiveness of these materials in optoelectronic devices. This work presents subpicosecond transient absorption (TA) data that probe the excited-state photophysics of samples with a continuum of intermolecular separation, from monomers in solution to high-concentration solid solution thin films analogous to OPV active layers. EnT times are calculated for each squaraine concentration, and pump-power dependence provides evidence for significant EnT despite a high preponderance of H-aggregation. Theoretical modeling of essential states supports the interpretation from TA spectra that excited states relax into more tightly packed H-aggregates. This work prompts further questions regarding a far-reaching mechanistic EnT bottleneck for molecular and polymeric BHJ devices.
关键词： H-aggregation,squaraine,organic photovoltaic,bulk heterojunction,exciton diffusion,energy transfer
更新于2025-09-23 15:19:57
-
Heterostructural CsPbX3-PbS (X=Cl,Br,I) Quantum Dots with Tunable Vis-NIR Dual Emission
摘要： Perovskite and chalcogenide quantum dots (QDs) are important nano semiconductors. It has been a challenge to synthesize heterostructural QDs combining perovskite and chalcogenide with tailorable photoelectronic properties. In this report, heterostructural CsPbX3-PbS (X=Cl, Br, I) QDs were successfully synthesized via a room temperature in-situ transformation route. The CsPbX3-PbS QDs show a tunable dual emission feature with the visible and near infrared (NIR) photoluminescence (PL) corresponding to CsPbX3 and PbS, respectively. Typically, the formation and evolution of the heterostructural CsPbBr3-PbS QDs with reaction time was investigated. Femtosecond transient absorption spectroscopy (TAS) was applied to illuminate the exciton dynamics in CsPbBr3-PbS QDs. The mild synthetic method and TAS proved perovskite to PbS energy transfer may pave the way toward high efficient QD photovoltaic and optoelectronic devices.
关键词： Perovskite,Photoluminescence,Dual Emission,Heterojunction,Quantum-Dots
更新于2025-09-23 15:19:57
-
Designed synthesis of microstructure and defect-controlled Cu-doped ZnO-Ag nanoparticles: exploring high-efficiency sunlight-driven photocatalysts
摘要： Cu-doped ZnO nanoparticles composited with Ag were synthesized by one-step sol-gel method in this work, aiming at highly photocatalytic activity and possible application under sunlight (especially near ultraviolet and visible light regions, 300-760 nm) irradiation. Scanning electron microscopy (SEM) shows that the introduction of Cu inhibits particle aggregation. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) reveal that Zn(Cu)O-Ag nanoparticles (CZA NPs) are composed of metallic Ag (Ag0) and Zn(Cu)O nanocrystals; while at the Cu concentration of higher than 2%, a little CuO nanocrystals appear. Transmission electron microscopy (TEM) results evidenced the well-defined formation of Zn(Cu)O-Ag and/or CuO-ZnO-Ag heterojunctions. UV–vis spectra display that the visible absorption of the samples is obviously enhanced after the Cu introduction. At a low Cu doping level (0.2%) and moderate Cu concentration (3~5%), the blue and green photoluminescence (PL) emission strength of the samples become very weak in comparison to other samples, indicative of the high separation of photogenerated electron-hole pairs. Reasonably, the higher photocatalytic degradation (complete degradation of methylene blue (MB) and methyl orange (MO) within 40 minutes under the simulated sunlight irradiation) are achieved in these cases: low Cu doping level (0.2%) and moderate Cu concentration (3~5%) in CZA NPs. Further, we checked the effects of other factors on the photocatalytic degradation for possible application. Our results suggest that one well-designed composite type such as element-doped Zn(M)O-Ag nano-heterojunction or complicated metal oxide-ZnO-Ag nanocomposites possessing suitable band structures for the separation and utilization of photo-generated carriers, will remarkably improve the photocatalytic performance of nano-ZnO under sunlight irradiation.
关键词： ZnO-Ag nanocomposites,heterojunction,sunlight irradiation,Cu-doped ZnO,photocatalytic degradation
更新于2025-09-23 15:19:57
-
One-step H2S reactive sputtering for 2D MoS2/Si heterojunction photodetector
摘要： A technique for directly growing two-dimensional (2D) materials onto conventional semiconductor substrates, enabling high-throughput and large-area capability, is required to realise competitive 2D transition metal dichalcogenide devices. A reactive sputtering method based on H2S gas molecules and sequential in-situ post-annealing treatment in the same chamber was proposed to compensate for the relatively deficient sulfur atoms in the sputtering of MoS2 and then applied to a 2D MoS2/p-Si heterojunction photodevice. X-ray photoelectron, Raman, and UV-visible spectroscopy analysis of the as-deposited Ar/H2S MoS2 film were performed, indicating that the stoichiometry and quality of the as-deposited MoS2 can be further improved compared with the Ar-only MoS2 sputtering method. For example, Ar/H2S MoS2 photodiode has lower defect densities than that of Ar MoS2. We also determined that the factors affecting photodetector performance can be optimised in the 8–12 nm deposited thickness range.
关键词： H2S gas,two-dimensional layered MoS2,reactive sputtering,heterojunction photodiode
更新于2025-09-23 15:19:57