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Bi4NbO8Cl {001} nanosheets coupled with g-C3N4 as 2D/2D heterojunction for photocatalytic degradation and CO2 reduction
摘要： Photocatalytic activity is largely restricted by insufficient photoabsorption and intense recombination between charge carriers. Here, we first synthesized Bi4NbO8Cl nanosheets with {001} exposing facets by a molten-salt growth method, which shows largely promoted photocatalytic performance for the degradation of tetracycline (TC) and bisphenol A (BPA) in comparison with Bi4NbO8Cl particles obtained by solid-state reaction. The 2D/2D Bi4NbO8Cl/g-C3N4 heterojunction photocatalysts were then fabricated via high-energy ball-milling and post-sintering to realize intimate interfacial interaction. The photocatalytic activity of all the Bi4NbO8Cl/g-C3N4 composites largely enhances compared to Bi4NbO8Cl nanosheets and g-C3N4, also far exceeding the mechanically-mixed Bi4NbO8Cl nanosheets and g-C3N4. The impact of different reaction parameters on the photocatalytic degradation activities was investigated, including catalyst concentration, pH value and TC concentration. In addition, Bi4NbO8Cl/g-C3N4 also presents improved photocatalytic CO2 reduction activity for CO production. The large enhancement on photocatalytic activity of Bi4NbO8Cl/g-C3N4 composites is owing to the synergistic effect of favorable 2D/2D structure and construction of type II heterojunction with intimate interfacial interaction, thus boosting the charge separation. The formation of type II heterojunction was evidenced by selective photo-deposition of Pt and MnOx, which demonstrate that the reductive sites and oxidative sites are on Bi4NbO8Cl nanosheets and g-C3N4, respectively. This work may provide some insights into fabrication of efficient visible-light driven photocatalysts for environmental and energy applications.
关键词： g-C3N4,photodegradation,Bi4NbO8Cl nanosheets,CO2 reduction,heterojunction
更新于2025-09-11 14:15:04
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High-speed heterojunction photodiodes made of single- or multiple-layer MoS2 directly-grown on Si quantum dots
摘要： Recently, chemical vapor deposition-grown molybdenum disulfide (MoS2) has been actively employed for MoS2/Si-wafer heterojunction (HJT) photodetectors due to the attractive optoelectronic properties. However, the MoS2/Si HJT is not so advantageous in that it exhibits low photoresponse due to the low light absorption despite the simple device structure. In addition, there is a limitation in achieving high-quality MoS2 films due to the defects at the MoS2/Si interface developed during the transfer of the MoS2 films to the target substrate, resulting from the restriction of the direct growth on the Si wafer. Here, we first report successful direct growth of single- and multi-layer MoS2 films on Si quantum dots (SQDs) multilayers (MLs) embedded SiO2 (SQDs:SiO2 MLs) substrates. The multilayer MoS2/SQDs HTJ photodiodes show response speed of rise time: ~60 ns/fall time: ~756 ns, highest than ever achieved, and detectivity of 6.1 x 10^13 cm Hz^1/2 W^-1. This excellent performance can be attributed to well formation of the HJT at the MoS2/SQDs:SiO2 interface by the direct growth, resulting in the reduction of the defects, thereby facilitating the carrier transport, and high light absorptivity of the SQDs:SiO2 MLs.
关键词： MoS2,Heterojunction,Photodiode,Si quantum dot,Response speed,Direct growth
更新于2025-09-11 14:15:04
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Preparation of visible-enhanced PbI2/MgO/ Si heterojunction photodetector
摘要： Fabrication and characterization of p-PbI2/MgO/n-Si photodetectors by pulsed laser deposition within (2.7-2.5) eV. The current-voltage and capacitance-voltage properties of PbI2/MgO/Si photodetector were investigated. The best responsivity of p-PbI2/MgO/n-Si photodetectors was ~ investigated using x-ray diffraction XRD, UV-Vis absorption and scanning electron microscope SEM. The XRD results revealed a single crystalline MgO with cubic structure along the (200) PLD under different deposition temperatures Ts were demonstrated for the first time. Structural, optical and morphological properties of nanostructured MgO and PbI2/MgO films were plane, while the PbI2 film deposited on MgO was a single crystalline with hexagonal phase along (001) plane. The optical energy gaps of PbI2 films deposited on MgO film were found to be perovskite solar cells, photodetectors, X-ray detectors, photoconductors, biological labeling and diagnostics, active matrix flat panel imagers, and γ-ray detectors [3, 4]. PbI2 films are usually prepared thermal evaporation, chemical methods, pulsed laser deposition, atomic layer deposition, and electron beam evaporation [5-8]. The wider optical energy gap MgO (7.3 eV at room temperature) is a non-toxic, high specific surface reactivity and cubic crystal structure with Fm-3m space group and transparent at the visible light. MgO films have been used in many [1, 2]. Lead iodide has been used in numerous applications, for example, light emitting diodes, Lead iodide has a hexagonal structure with optical band gap around 2.2eV at room temperature Keywords: PbI2; MgO; PLD; Heterojunction; Silicon; photodetector; Deposition temperature 0.88A/W at 410nm when the photodetector was prepared at Ts = 45°C.
关键词： Silicon,photodetector,MgO,Deposition temperature,PbI2,Heterojunction,PLD
更新于2025-09-11 14:15:04
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An in situ inward etching strategy for constructing a p-p heterojunction Cu2S/Cu2-xSe material based on brass as an effective counter electrode for quantum dot sensitized solar cells
摘要： Composite counter electrode Cu2S/Cu2-xSe nanosheets based on brass are fabricated by an in situ inward etching method using Cu(OH)2 nanotubes as a template. Due to superior electrocatalytic activity towards the polysulfide electrolyte, the quantum dot-sensitized solar cells constructed with Cu2S/Cu2-xSe counter electrodes deliver a considerable power conversion efficiency of 6.10% under 1 sun illumination, which is a 22% enhancement compared to that of Cu2S/brass (5.00%). According to the results of BET testing, solid-state J-V measurements and transient photocurrent measurements, the enhanced electrocatalytic activity is attributed to two aspects: one is the larger surface active area, which provides more active sites for the electrolyte, and the other is the formation of a p-p heterojunction for more effective electron transfer in the counter electrode. In addition, the band energy structure of the Cu2S/Cu2-xSe heterojunction is further investigated to understand the behavior of interfacial electron transfer. Finally, the outstanding electrochemical catalytic activity and stability of the Cu2S/Cu2-xSe counter electrode are proved by electrochemical impedance spectroscopy, Tafel polarization and cyclic voltammetry results for symmetric dummy cells, demonstrating that the Cu2S/Cu2-xSe composite is a desirable material as a counter electrode for quantum dot sensitized solar cells.
关键词： Cu2S/Cu2-xSe CE,Electrochemical catalytic activity,QDSCs,p-p heterojunction,Stability
更新于2025-09-11 14:15:04
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Facile approaches to prepare n-ZnO/(i-ZnO)/p-GaN heterojunction light-emitting diodes with white-light-electroluminescence
摘要： White-light-emitting diode (LED) with effective energy conservation and long service life could be employed in numerous applications. In this study, the high-performance n-ZnO films were first prepared via pulsed laser deposition on p-GaN substrates and then the n-ZnO/p-GaN heterojunction LED was fabricated. This LED exhibits blue and yellow light emission, and their emission intensities can be tuned by adjustment of the fabrication parameters (e.g. oxygen pressure) and/or by introduction of a semi-insulating i-ZnO layer to form a p-GaN/i-ZnO/n-ZnO heterojunction. Thus, a facile approach has been proposed for the preparation of white LED.
关键词： n-ZnO,white-light-electroluminescence,heterojunction,p-GaN,light-emitting diodes
更新于2025-09-11 14:15:04
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[Frontiers of Nanoscience] Nanostructured Thin Films Volume 14 || Spectroscopic and electrical properties of hybrid thin films for solar cell applications
摘要： Third-generation solar cells are designed in order to be able to fabricate thin film solar cells with solution deposition techniques and to obtain high-efficiency solar cells. There are two types of well-known solution-phase-fabricated solar cells: (1) multilayer structure and (2) bulk heterojunction (BHJ) solar cells. Multilayer structure solar cells are fabricated layer by layer of semiconductors, whereas BHJ solar cells consist of two semiconducting materials mixed in one common solvent and deposited onto a conductive glass substrate. Compared with multilayer structures, the BHJ method enables a reduction of the electron pathways between the two materials. One type of solution process for BHJ solar cells is the polymer-nanocrystal BHJ (or hybrid) solar cell. Hybrid BHJ solar cells are fabricated by blending the conducting polymer and inorganic colloidal NCs, and thus combining the properties of both organic and inorganic nanocrystals semiconductors. In this process, the performance of hybrid BHJ solar cells is influenced by the nanocrystals’ shape, solubility, and surface modification, as these properties are believed to affect the crystals’ incorporation in the polymer matrix.
关键词： bulk heterojunction,charge transport,ligand exchange,solar cells,nanocrystals,thin films,polymer
更新于2025-09-11 14:15:04
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Charge Carrier Dynamics in Electron-Transport-Layer-Free Perovskite Solar Cells
摘要： Better understanding the carrier dynamics process in electron transport layer (ETL) -free perovskite solar cells (PSCs) enables the further exploration of the perovskite potential and corresponding device structure design. Herein, ETL-free perovskite/transparent conductive film SnO2:F(FTO) contact with different perovskite thickness illuminated by varied light intensity was investigated by scanning probe microscopy technology. Strong charge transfer is occurred at the perovskite/FTO contact, evidenced by the variations of both surface contact potential and local current value. Mott-Schottky analysis based on capacitance-voltage measurements suggests that the interface property of perovskite/FTO contact is similar to the perovskite/TiO2/FTO structure, make it ideal to fabricate ETL-free PSCs. The cross-sectional surface potential drop was found to be mainly located at the CH3NH3PbI3/FTO heterojunction, suggesting a single diode junction in the ETL -free PSCs. Furthermore, a single-side abrupt p-n++ junction model is employed to illustrate the energy level alignment at the perovskite/FTO contact. This study will be helpful for understanding the carrier dynamics process and thus achieving high device efficiency in the ETL-free PSCs.
关键词： perovskite solar cells,Carrier dynamics,surface potential,scanning probe microscopy,heterojunction
更新于2025-09-11 14:15:04
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AIP Conference Proceedings [AIP Publishing 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - Fes, Morocco (25–27 March 2019)] 15th International Conference on Concentrator Photovoltaic Systems (CPV-15) - P-type SiOx front emitters for Si heterojunction solar cells
摘要： We have applied p-type nanocrystalline silicon-oxide (p-SiOx) as front emitter in silicon heterojunction solar cells. The evolution of structural, optical, and electrical properties of p-SiOx as a function of the carbon-dioxide/silane flow rate ratio used in the gas mixture has been investigated, comparing also the film characteristics with those of p-type amorphous and nanocrystalline silicon thin films often used in the cells. Selected p-SiOx films with suitable electrical properties have been inserted in silicon heterojunction solar cells based on n-type FZ c-Si <100> wafers, passivated with ultrathin intrinsic a-Si:H buffers. Improvement of all the photovoltaic parameters has been observed with the emitter with higher oxygen content. The results have been correlated with the increased transparency and enhanced field-effect passivation obtained thanks to the presence of sufficient carbon dioxide in the gas mixture for the p-SiOx layer growth.
关键词： field-effect passivation,silicon heterojunction solar cells,p-type nanocrystalline silicon-oxide,optical and electrical properties,carbon-dioxide/silane flow rate ratio
更新于2025-09-11 14:15:04
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AIP Conference Proceedings [AIP Publishing INTERNATIONAL SYMPOSIUM ON GREEN AND SUSTAINABLE TECHNOLOGY (ISGST2019) - Perak, Malaysia (23–26 April 2019)] INTERNATIONAL SYMPOSIUM ON GREEN AND SUSTAINABLE TECHNOLOGY (ISGST2019) - Advances with resist-free copper plating approaches for the metallization of silicon heterojunction solar cells
摘要： The metallization of silicon heterojunction (SHJ) solar cells by selective Cu electroplating without any resist-mask is in development. A thin multi-functional PVD Cu-Al stack is deposited to mask the ITO and to promote homogeneous current distribution for simultaneous bifacial plating. This investigation reviews different approaches to perform the Al-patterning – by printing of a metallic ink, laser metal transfer or selective metal etching – to produce a metal-seed susceptible to plate selectively against the self-passivated Al surface. This NOBLE – native oxide barrier layer for selective electroplated, metallization allows reaching a first promising efficiency of 20.0% on a full area SHJ solar cell with low contact resistivity to ITO. This simultaneous bifacial metallization features several advantages: low temperature processing, high metal conductivity of plated copper, no organic masking and low material costs (almost Ag-free).
关键词： bifacial plating,silicon heterojunction solar cells,resist-free,metallization,PVD Cu-Al stack,Cu electroplating
更新于2025-09-11 14:15:04
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Designing WO <sub/>3</sub> /CdIn <sub/>2</sub> S <sub/>4</sub> type-II heterojunction with both efficient light absorption and charge separation for enhanced photoelectrochemical water splitting
摘要： WO3 is a typical photoanode material for photoelectrochemical (PEC) water splitting. However, the PEC activity of WO3 photoanode is limited by its poor visible light absorption as well as severe carrier recombination at the electrode/electrolyte interface. Herein, we integrate small-band-gap CdIn2S4 nanoplates with hydrothermally grown WO3 nanowall arrays to form into a three-dimensional (3D) WO3/CdIn2S4 heterojunction through a chemical bath deposition process. The synthesis parameters of CdIn2S4, including reaction time and temperature, have been tuned to optimize the PEC performance. The WO3/CdIn2S4 composite photoanode prepared at 50 °C for 5 h exhibits the highest photocurrent of 1.06 mA cm?2 at 1.23 V versus reversible hydrogen electrode without the presence of holes scavenger, which is about 5.9 times higher than that of bare WO3 photoanode. The band alignment between WO3 and CdIn2S4 is confirmed by the ultraviolet–visible light absorption spectra and ultraviolet photoelectron spectra. The PEC performance enhancement is attributed to the enhanced light absorption benefiting from the small band gap of CdIn2S4 and efficient charge separation originating from the type-II alignment between WO3 and CdIn2S4.
关键词： photoanode,WO3,CdIn2S4,photoelectrochemical water splitting,heterojunction
更新于2025-09-11 14:15:04