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The design of a polyaniline-decorated three dimensional W18O49 composite for full solar spectrum light driven photocatalytic removal of aqueous nitrite with high N2 selectivity
摘要： Photocatalysis using solar energy is the most promising green technology for nitrite removal. However, effective photocatalytic performance is often challenged by the limited light absorption, utilization of expensive noble metals and undesired products (nitrate and ammonium). Here, we report for the first time that a full solar light response polyaniline-decorated three dimensional W18O49 composite (PANI@W18O49), a noble metal-free photocatalyst, possesses excellent photocatalytic activity for aqueous nitrite removal with high N2 selectivity. The prepared sample was thoroughly identified via XRD, Raman, FTIR, SEM, TEM, UV–vis DRS and PL. The catalytic results demonstrated that over 80% N2 selectivity (initial concentration 1.0 mM) was achieved through the PANI@W18O49 without sacrificial agent under 300 W Xe lamp irradiation for 60 min. Such advantages were attributed to the built-in junction between n-type W18O49 and p-type PANI, offering suitable redox levels of electron-hole pairs for NO2? reaction. The modification of PANI also benefited the light harvesting ability and activated carriers migration, the calculated rate constant of PANI@W18O49 is about four times as high as that of W18O49. The current study not only prepared a promising photocatalyst, but also provides new insights into improving the photocatalytic activity and N2 selectivity for nitrite treatment.
关键词： Nitrite,Polyaniline,Tungsten oxide,Full solar spectrum light driven,Photocatalysis
更新于2025-09-23 15:23:52
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Geometry error analysis in solar Doppler difference navigation for the capture phase
摘要： Deep space exploration missions continue to become more ambitious, driving the need to investigate autonomous navigation systems that are accurate and timely. The solar Doppler difference navigation is a newly-developed and promising celestial autonomous navigation method for use, particularly in the crucial capture period. In this paper, we present novel analyses for three error sources for the solar Doppler difference navigation from the perspective of geometry, motivated with a Mars Deep Space Exploration example. The geometry error sources include the area overlap rate of the direct and the reflected solar light sources, the spread effects related to the time difference of arrival (TDOA) of light, and the solar rotation Doppler difference error. The area overlap rate and the spread effects of TDOA can be utilized to assess the overlap degree of the direct source and the reflected source in both space and time. Theoretical analyses and simulation results demonstrate that the direct and the reflected light sources can be accurately approximated as the same source. The solar rotation Doppler difference error is explored using a velocity error model. This model forms a hemi-ellipsoid that can be utilized to compensate the Doppler error caused by the solar rotation. The three errors decline with the deep space explorer approaching Mars, which means that the performance of the solar Doppler difference navigation method continuously improves in the critical capture period. These results can offer a reference for the system design of the solar Doppler difference navigation.
关键词： error analysis,solar spectrum,Doppler effects,navigation,geometry error
更新于2025-09-23 15:22:29
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[IEEE 2019 11th International Conference on Electronics, Computers and Artificial Intelligence (ECAI) - Pitesti, Romania (2019.6.27-2019.6.29)] 2019 11th International Conference on Electronics, Computers and Artificial Intelligence (ECAI) - Design of an LED-based solar spectrum simulator for porphyrin dye-sensitized solar cell characterization
摘要： This paper presents the design considerations for a special solar spectrum simulator, based on LED technology, specifically conceived for the characterization of porphyrin-based dye-sensitized solar cells.
关键词： solar spectrum,photovoltaics,solar simulator,DSSC,LED
更新于2025-09-23 15:21:01
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Performance Analysis of Submerged Polycrystalline Photovoltaic Cell in Varying Water Conditions
摘要： Exploring the underwater solar energy by solar photovoltaic (PV) cells leads to a huge advantage by utilizing the humongous space of water covered by the earth’s surface. Even though the amount of solar radiation decreases with the depth of the water, water provides sustainable cooling and cleaning for solar PV cells underwater. There are many challenges and constraints to develop solar PV cells underwater because they are mostly calibrated and amenable to space, dryland, terrestrial, etc., and the solar spectrum is prone to get narrower with the depth of the water. The implementation of solar PV cells underwater is pliable in various commercial and defense applications, such as sensors, water monitoring systems, autonomous vehicles, underwater gliders, etc. In this article, first, a mathematical model has been developed for the solar cell spectrum to incorporate the changes in the solar irradiance with the depth of the water. Furthermore, an experimental setup was designed and implemented to mimic an underwater environment. The performance of the polycrystalline encapsulated solar cell was studied based on the different types of water and the depth of the solar cell underwater. This article manifests that there is a sufficient amount of underwater solar power that can be utilized using PV cells to operate various devices and systems.
关键词： polydimethylsiloxane (PDMS),Photovoltaic (PV) cells,underwater solar power,polycrystalline solar cell,solar spectrum,water salinity,solar irradiance
更新于2025-09-16 10:30:52
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The Influence of Solar Spectrum and Concentration Factor on the Material Choice and the Efficiency of Multijunction Solar Cells
摘要： In this work, we revisit the theoretical study on the conversion efficiency of series-connected multijunction solar cells. The theoretical method, based on the detailed balance model, is then applied to devices with 2 to 6 junctions under different illumination conditions. As results, (i) we show that the peaks in the efficiency distribution occur for recurrent values of bottom junction bandgap energy corresponding to atmospheric absorption in the solar spectrum, and (ii) we demonstrate that variations in the number of junctions, in the incident solar spectrum, and in the concentration factor lead to changes in the optimum bandgap energy set but that the bottom junction bandgap energy only changes among the recurrent values presented before. Additionally, we highlight that high conversion efficiencies take place for a broad distribution of bandgap energy combination, which make the choice of materials for the device more flexible. Therefore, based on the overall results, we propose more than a hundred III-V, II-VI and IV semiconductor material candidates to compose the bottom junction of highly efficient devices.
关键词： conversion efficiency,material choice,concentration factor,Multijunction solar cells,solar spectrum
更新于2025-09-16 10:30:52
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Optimization and maximum efficiency of concentrating photovoltaic cell‐gas turbine system with spectrum splitting
摘要： The spectrum splitting system (SSS) is an efficient approach to relieve the energy losses in the solar cell and boost the efficiency of solar energy utilization. A model of the concentrated solar spectrum splitting photovoltaic (PV) cell-gas turbine (GT) hybrid system is established to evaluate the performance of the system and predict the maximum efficiency. The numerical calculations show that the area ratio of the solar collector to the PV cell significantly affects the maximum efficiency of the spectrum system, but most of the previous studies are not considered. The maximum efficiency of the system is 50.6% when the parameters including the cell voltage, collector temperature, and band gap energy of the PV cell are optimized at the same areas of the collector and PV cell. The proposed SSS can achieve the maximum efficiency of 52.3% when the area ratio of the collector to the PV cell is further optimized. The results obtained are compared with those of a single concentrating PV cell or solar-powered GT, and consequently, the advantages of a concentrating spectrum splitting PV cell-GT hybrid system are revealed.
关键词： maximum efficiency,optimization,solar spectrum splitting,gas turbine,photovoltaic cell
更新于2025-09-12 10:27:22
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Disorder Engineering in Monolayer Nanosheets Enabling Photothermic Catalysis for Full Solar Spectrum (250 <b>-</b> 2500?nm) Harvesting
摘要： A persistent challenge in classical photocatalyst systems with extended light absorption is the unavoidable trade-off between maximizing light harvesting and sustaining high photoredox capability. Alternatively, cooperative energy conversion through photothermic activation and photocatalytic redox is a promising yet unmet scientific proposition that critically demands a spectrum-tailored catalyst system. Here, we construct a solar thermal-promoted photocatalyst, an ultrathin “biphasic” ordered–disordered D-HNb3O8 junction, which performs two disparate spectral selective functions of photoexcitation by ordered structure and thermal activated conversion via disordered lattice for combinatorial photothermal mediated catalysis. This in situ synthetically immobilized lattice distortion, constrained to a single-entity monolayer structure not only circumvents interfacial incompatibility but also triggers near-field temperature rise at the catalyst–reactant complexes’ proximity to promote photoreaction. Ultimately, a generic full solar conversion improvement for H2 fuel production, organic transformation and water purification is realized.
关键词： redox reaction,photothermic catalysis,defect engineering,order–disorder,full solar spectrum
更新于2025-09-10 09:29:36
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The Analysis of Starlight (Two Centuries of Astronomical Spectroscopy) || The analysis of sunlight: the earliest pioneers
摘要： The story of solar, and hence also of astronomical spectroscopy, began in 1666 when the young Isaac Newton (1642–1726) wrote these famous words: I procured me a Triangular glass-Prisme, to try therewith the celebrated Phaenomena of Colours. And in order having darkened my chamber, and made a small hole in my window-shuts, to let in a convenient quantity of the Suns light, I placed my Prisme at his entrance, that it might thereby be refracted to the opposite wall. [1]
关键词： sunlight,solar spectrum,spectroscopy,Isaac Newton,prism
更新于2025-09-10 09:29:36
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Fundamental molecules of life are pigments which arose and co-evolved as a response to the thermodynamic imperative of dissipating the prevailing solar spectrum
摘要： The driving force behind the origin and evolution of life has been the thermodynamic imperative of increasing the entropy production of the biosphere through increasing the global solar photon dissipation rate. In the upper atmosphere of today, oxygen and ozone derived from life processes are performing the short-wavelength UV-C and UV-B dissipation. On Earth’s surface, water and organic pigments in water facilitate the near-UV and visible photon dissipation. The first organic pigments probably formed, absorbed, and dissipated at those photochemically active wavelengths in the UV-C and UV-B that could have reached Earth’s surface during the Archean. Proliferation of these pigments can be understood as an autocatalytic photochemical process obeying non-equilibrium thermodynamic directives related to increasing solar photon dissipation rate. Under these directives, organic pigments would have evolved over time to increase the global photon dissipation rate by (1) increasing the ratio of their effective photon cross sections to their physical size, (2) decreasing their electronic excited state lifetimes, (3) quenching radiative de-excitation channels (e.g., fluorescence), (4) covering ever more completely the prevailing solar spectrum, and (5) proliferating and dispersing to cover an ever greater surface area of Earth. From knowledge of the evolution of the spectrum of G-type stars, and considering the most probable history of the transparency of Earth’s atmosphere, we construct the most probable Earth surface solar spectrum as a function of time and compare this with the history of molecular absorption maxima obtained from the available data in the literature. This comparison supports the conjecture that many fundamental molecules of life are pigments which arose, proliferated, and co-evolved as a response to dissipating the solar spectrum, supports the thermodynamic dissipation theory for the origin of life, constrains models for Earth’s early atmosphere, and sheds some new light on the origin of photosynthesis.
关键词： photosynthesis,thermodynamic dissipation,UV-C,solar spectrum,UV-B,Archean,organic pigments,origin of life
更新于2025-09-09 09:28:46
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Revision of the Sun’s Spectral Irradiance as Measured by SORCE SIM
摘要： The Spectral Irradiance Monitor (SIM) instrument on board the Solar Radiation and Climate Experiment (SORCE) performs daily measurements of the solar spectral irradiance (SSI) from 200 to 2400 nm. Both temporal and spectral corrections for instrument degradation have been built on physical models based on comparison of two independent channels with different solar exposure. The present study derives a novel correction for SIM degradation using the total solar irradiance (TSI) measurements from the Total Irradiance Monitor (TIM) on SORCE. The correction is applied to SIM SSI data from September 2004 to October 2012 over the wavelength range from 205 nm to 2300 nm. The change in corrected, integrated SSI agrees within 0.1 W m?2 (1σ ) with SORCE TIM TSI and independently shows agreement with the SATIRE-S and NRLSSI2 solar models within measurement uncertainties.
关键词： Solar spectral irradiance,Degradation correction,Solar spectrum,Solar variability,Solar cycle
更新于2025-09-04 15:30:14