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Plasmonic MoO2 as co-catalyst of MoS2 for enhanced photocatalytic hydrogen evolution
摘要： Generally, photocatalytic water splitting on MoS2 nanomaterials is restricted owing to the high carrier recombination and limited utilization of the visible light. This study describes the enhancement of the MoS2-catalysed hydrogen evolution by incorporating metallic MoO2 as a co-catalyst introduced by coupling with MoS2 nanosheets through a facile calcination strategy, forming a Schottky junction between MoO2 and MoS2. The localized surface plasmon resonance effect induced by the oxygen vacancies and favourable Fermi lever position of MoO2 lead to a broad spectral response and a significant improvement in the exciton generation and dissociation. The electron gets transferred from the conduction band (CB) of MoS2 to MoO2, wherein MoO2 acts as an ‘electron pool’ that gathers the photoexcited electrons, which are rapidly shuttled to the surface of MoO2, where the redox reaction occurs due to its great metallic conductivity. Resultantly, a 242% increment in the production of hydrogen gas by MoS2/MoO2 is achieved in comparison with that of the MoS2 nanosheets.
关键词： Photocatalytical hydrogen production,co-catalysts,MoS2/MoO2,LSPR effect,Schottky junction
更新于2025-09-19 17:13:59
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Enhanced photoresponse and surface charge transfer mechanism of graphene-tungsten disulfide heterojunction
摘要： Two dimensional (2D) materials based heterostructures have gained profound interest in optoelectronics and electronic technology due to additional functionalities over the individual structures. This study demonstrates the fabrication and characterization of van der Waal heterostructure by selective coverage of graphene (Gr) with tungsten disulfide (WS2). The electrical transport measurements divulge the tweaking of charge carriers in graphene after WS2 coverage. Such architecture provides route towards the formation of heterojunction within graphene FET based on surface charge transfer between Gr/WS2 heterointerface. Furthermore, the exposure of device towards deep ultraviolet light (DUV) enhances the charge transfer mechanism and as a result more pronounced junction is observed. The photoelectrical characterization of heterostructure is also investigated by calculating detectivity (D*), external quantum efficiency (EQE) photoresponsivity (Rλ). Our results suggest that 2D heterostructures in combination with DUV irradiations are more efficient and suitable choice to selectively tune the properties of 2D material-based optoelectronic devices.
关键词： p-n junction,Tungsten disulfide,Graphene,Photoresponse,Deep ultraviolet light (DUV),Heterostructure
更新于2025-09-19 17:13:59
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Solar Panels and Photovoltaic Materials || Multicell Design for Concentrated Photovoltaic (CPV) Module
摘要： Despite its highest efficiency, concentrated photovoltaic (CPV) technology is still finding its way into the current photovoltaic market which is saturated with conventional flat-plate photovoltaic systems. CPV systems have a great performance potential as they utilize third-generation multi-junction solar cells. In the CPV system, the main aspect is its concentrating assembly design which affects not only its overall performance but also its operation and fabrication. Conventional CPV design targets to use individual solar concentrator for each solar cell. The main motivation of this chapter is to propose a novel concentrating assembly design for CPV that is able to handle multiple solar cells, without affecting their size, using single solar concentrator. Such proposed design, named as multicell concentrating assembly (MCA), will not only reduce the assembly efforts during CPV module fabrication, but it will also lower the overall system cost with simplified design. In this chapter, a detailed design methodology of multicell concentrating assembly (MCA) for CPV module is presented and developed with complete verification through ray tracing simulation and field experimentation.
关键词： homogenizer,CPV,concentrator photovoltaic,multi-junction solar cell,novel concentrator
更新于2025-09-19 17:13:59
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Solar Hydrogen Production || Solar photovoltaics (PV)
摘要： The photovoltaic conversion is based on the photovoltaic effect, that is, on the conversion of the light energy coming from the sun into electrical energy. To carry out this conversion, devices called solar cells are used, constituted by semiconductor materials in which a constant electric field has been created artificially (by means of a pn junction). Next, we will try to understand in a qualitative way how light is converted into electricity. This requires remembering some concepts of physics and chemistry.
关键词： light energy,solar cells,pn junction,photovoltaic effect,semiconductor materials,electrical energy
更新于2025-09-19 17:13:59
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High Responsivity and High Rejection Ratio Self-Powered Solar-Blind Ultraviolet Photodetector Based on PEDOT:PSS/β-Ga2O3 Organic/Inorganic p-n Junction
摘要： A high responsivity self-powered solar-blind deep UV (DUV) photodetector with high rejection ratio was proposed based on inorganic/organic hybrid p-n junction. Owing to the high crystalized β-Ga2O3 and excellent transparent conductive polymer PEDOT:PSS, the device exhibited ultrahigh responsivity of 2.6 A/W at 245 nm with a sharp cut off wavelength at 255 nm without any power supply. The responsivity is much larger than that of previous solar-blind DUV photodetectors. Moreover, the device exhibited an ultrahigh solar-blind/UV rejection ratio (R245 nm /R280 nm) of 103, which is two orders of magnitude larger than the average value ever reported in Ga2O3-based solar-blind photodetectors. In addition, the photodetector shows a narrow band-pass response of only 17 nm in width. This work might be of great value in developing high wavelength selective DUV photodetector with respect to low cost for future energy-efficient photoelectric devices.
关键词： Self-Powered,PEDOT:PSS/β-Ga2O3,Plasmonics and Optoelectronics,Organic/Inorganic p-n Junction,Energy Conversion and Storage,High Rejection Ratio,High Responsivity,Solar-Blind Ultraviolet Photodetector
更新于2025-09-19 17:13:59
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Redefinition the quasi-Fermi energy levels separation of electrons and holes inside and outside quantum wells of GaN based multi-quantum-well semiconductor laser diodes
摘要： Both accurate experiments and a self-consistent theoretical simulation using the near-ABC or ab initio method have uncovered the anomalous changes in the junction voltage (Vj ) of GaN-based lasers (Li et al 2013 Appl. Phys. Lett. 102 123501, Feng et al 2018 J. Phys. D: Appl. Phys. 51 095102 and Feng et al Appl. Phys. B 124 39). Here, further accurate emission spectral characteristics and band-gap simulation of a GaN based laser diodes (LDs) confirmed that previous researchers may have confused the junction voltage (Vj ) and the separation between the two Fermi levels of electrons and holes in the active region divided by the electronic charge (ΔEf /e). For the multiple-quantum wells (MQWs), there are obvious differences between them. For an ideal GaN-based LDs, despite the increase in junction voltage, physical quantities including the separation between the two Fermi levels of electrons and holes in the MQW region, and the optical net gain remain unchanged beyond the threshold region after an unpredictable sharp increase in the threshold region.
关键词： multi-quantum-well (MQW),steady state,junction voltage,quasi-Fermi energy levels separation,GaN based laser diodes (LD)
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Cost-Efficiency Trade-off of Silicon Solar Cells for use in Perovskite-Silicon Tandem Modules
摘要： We use techno-economic analysis to examine the potential of low-cost, lower-efficiency multi-crystalline silicon bottom cells in perovskite-silicon tandem solar cells, compared to high-efficiency, higher-cost mono-crystalline silicon cells. Two representative tandems, a low-cost and a high-efficiency device, are examined and compared based on levelized cost of electricity (LCOE) in current and future utility and residential systems. This analysis is then extended to explore the impact of top cell bandgap and top cell module cost, thus providing broader insight into the effect of variations and uncertainty in the properties of the perovskite top cell, as well as yielding implications for the use of other materials, such as cadmium telluride, in a tandem solar module. A clear case for the value of low-cost silicon for use as a silicon bottom cell is demonstrated.
关键词： techno-economic,perovskite,tandem,silicon,multi-junction
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - In Situ Transmission Electron Microscopy: A Powerful Tool for the Characterization of Carrier-Selective Contacts
摘要： This paper investigates the manufacturability-aware process of p-n junction formation for photovoltaic cells involving with Si nanoparticle layer. The furnace-based dopant diffusion process of forming a p-n junction consumes a substantial amount of energy. In addition, repetitive production steps prevent the possibility of Si ink-based cells integrating onto flexible substrates. This research examined the local heating dopant diffusion process by using a fiber laser at a wavelength of 1064 nm. The infrared beam is delivered onto the wafer stack with a nanoparticle carbon layer and n-type Si ink layer on p-type Si substrates. The nanoparticle carbon film absorbs infrared beam energy and converts photon energy as a thermal source to diffuse the n-type dopant in Si ink into the p-type Si wafer. The Si ink in this paper contains a mixture of Si nanoparticles and an n-type spin-on dopant solution. The TEM results show that Si nanoparticles are uniformly dispersed on the Si wafer surface. This research investigated sheet resistance as a function of laser parameters, including laser power, scanning speed, and pulse frequency for the samples coated with Si ink. Secondary ion mass spectroscopy measurements indicate the presence of an n-type dopant in p-type substrates, with an approximate diffusion depth of 100 nm. The results indicate that the proposed infrared laser treatment technique is promising for the formation of p-n junctions with Si ink-based photovoltaic cells.
关键词： Flexible photovoltaic cell,fiber laser,pn junction,spin-on dopant (SOD),silicon ink,carbon nanoparticle,silicon nanoparticle
更新于2025-09-19 17:13:59
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Temperature Sensing Characteristics and Long Term Stability of Power LEDs Used for Voltage vs. Junction Temperature Measurements and Related Procedure
摘要： A detailed study about the direct measurement of junction temperature TJ of off-the-shelf power light emitting diodes (LED) is presented. The linear dependence on temperature of the voltage drop across the device terminals at a constant current is in particular exploited and fully characterized, in the temperature range from T = 35 ?C to 135 ?C, with tests repeated at one thousand different probe currents. The accurate experimental data, obtained on several LED samples bearing two different part numbers, are reported, showing that they exhibit a high degree of linearity in wide current ranges, a circumstance that allows for a fast and reliable calibration as sensors. The measurement error is also fully characterized in terms of repeatability and stability over time, with measurements repeated after 600, 900, 1200 and 1800 hours of applied electro-thermal stress, demonstrating that the relevant sensor parameters stabilize after a few hundred hours of operation. A full set of parameters is provided for the two device models, allowing the direct use of each LED for the self-monitoring of the junction temperature and ensure compliance with their safe operating area over time. Moreover, a procedure and a simple circuit for the real time measurement of TJ , while the LED is on, are presented. The procedure does not require a stable current source, and relies instead on the application of a sub-threshold current ramp for such a short time that the change in the output light is not perceived by human eyes.
关键词： junction temperature,diode sensors,light emitting diodes,temperature sensors,LED
更新于2025-09-19 17:13:59
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Specifications of Photovoltaic Pumping Systems in Agriculture || Photovoltaic Energy: Basic Principles
摘要： The sun is a star which provides nearly 95% of its energy to generate nearly all the energy available on the earth. In fact, the earth energy is a direct or indirect conversion form of the sun’s lights. For instance, the solar heat ensures the plants evaporation-transpiration by converting the sunlight energy into storable chemical form through the photosynthesis process, which allows the fauna and flora to be maintained in the earth. Moreover, the sunlight is the source of generating wind and wave energies, by causing temperature difference in the atmosphere. Additionally, sunlight generates the photothermal and photovoltaic energies, which are used to provide electrical and heat energies. Consequently, sun means life.
关键词： P-N junction,Silicon atom,Solar radiation,Photovoltaic energy,Solar cell efficiency
更新于2025-09-19 17:13:59