Solar Photons Research Articles

Stokes and anti-Stokes emission characteristics of Er3+/Yb3+ co-doped zinc tellurite glasses under 377 and 1550 nm excitations for solar energy conversion application

One of the best rare earth combinations for down- and up-converting the solar photons is Er3+/Yb3+. Therefore, at present, by using the traditional melt quench technique, zinc tellurite glasses doped with Er3+ and Er3+/Yb3+ were characterised. Several methods of down-conversion that result in the emission of 1000 nm from the acceptor (Yb3+) under excitation of donor (Er3+) were studied. On the other hand, the impact of acceptor (Yb3+) concentration and excitation pump power on the excited state absorption and its influence on the up-conversion emission (1000 nm) properties were investigated in detail under 1535 nm excitation. The studies on emission and decay results are discovered to be very significant. Suggesting that these glasses when used as conversion layers, can append the conversion efficiency of Si-based solar cells.

Numerical optimization of cesium tin-germanium triiodide/antimony selenide perovskite solar cell with fullerene nanolayer

SCAPS-1D platform was used to simulate a solar cell with FTO/CdS/Sb2Se3/CuInSe2/Au structure which was recently fabricated by Liu et al. (2022) [1] [Journal of Energy Chemistry68 521–528 (2022)] and a very similar result was obtained. Reported parameters were Fill Factor (FF) = 53.60 %, short circuit current density (JSC) = 26.18 mA/cm2, open circuit voltage (VOC) = 0.37 V, and power conversion efficiency (PCE) = 5.19 %, while simulated parameters were FF of 54.68 %, JSC of 27.54 mA/cm2, VOC of 0.36 V, and PCE = 5.55 %. The advancements have been evaluated by analyzing FTO/CdS/Sb2Se3/CuInSe2/Au and FTO/C60/Sb2Se3/CuInSe2/Au configurations, serving as the reference cells. To improve the cell performance, the CdS layer was replaced with another layer (C60) which shows excellent electron transport properties. Replacing the CdS layer with C60 led to an increase in the power conversion efficiency by 65 % (from 5.55 % up to 9.20 %). In photovoltaic systems, the PCE constitutes a pivotal parameter that can be enhanced through the absorption of a broad spectrum of incident photons. Consequently, the implementation of two absorber layers within a solar cell, each characterized by a graded band gap energy, enables the capture of solar photons over a more extensive spectral range. Therefore, a perovskite containing a band gap of 1.5 eV, lead-free, and Sn-based was used as the second absorber layer in the device. Therefore, a solar cell with FTO/C60/CsSn0.5Ge0.5I3/Sb2Se3/CuInSe2/Au structure was simulated, and significant results were achieved. Results showed that inserting the CsSn0.5Ge0.5I3 layer led to an increase in PCE up to 11.42 %.

Design of 600 WP Solar Power Plant for Juice Vendors Through Off-Grid System

Solar power plants (PLTS) generate electricity from the energy of solar photons. Solar cells, or solar cells made of crystalline silicon, are examples of solar panels that generate electricity through the photovoltaic effect. Thus, the construction of solar power plants (PLTS) is one of the right choices to save energy. The purpose of this study is to utilize the energy that is owned and to introduce it to the surrounding community. The community has widely used solar power generation (PLTS) technology, one of the main components of solar power plants is solar photovoltaic technology, which is used to operate juice blenders, cup sealers, and energy-efficient lighting. PLTS functions as an alternative energy source to help juice traders. Based on solar energy for this off-grid system, it has a power capacity of 3 x 200 WP. This monocrystalline solar panel also has a 300 Ah VRLA battery, a 2000 W inverter, and a 50 A solar charger controller (SCC). In addition, the PLTS off-grid system for juice traders has blender equipment, cup sealers, and lighting with an average power rating of 600 Watts. With an efficiency calculation of 80%, this system can be fully used to support business operations. This study is to develop and Design a 600-watt peak Solar Power Plant using an off-grid system for juice vendors that costs Rp. 22,000,000, including all essential components and services needed to ensure that the system can operate properly

Quantifying External Energy Inputs for Giant Planet Magnetospheres

AbstractThe long‐standing “energy crisis” at the giant planets refers to the anomalous heating of planetary thermospheres compared to the available energy from solar irradiance. The coupling between planetary magnetospheres and their upper atmospheres is thought to address these crises, though the sources and pathways of energy transport have not been fully explored at each system. In particular, the total available energy from the upstream solar wind at each planet has not been comprehensively quantified. Here we apply recently developed models of energy conversion by magnetic reconnection and the Kelvin‐Helmholtz instability to each of the Giant Planets, providing estimates of the average external energy inputs for each system between 1985 and 2020. We find that external energy associated with solar‐wind‐magnetospheric coupling significantly exceeds that from solar extreme ultraviolet photons. While internal energy sources are known to dominate at Jupiter and Saturn, external sources may be significant at Uranus and Neptune.

Optimization of solar energy using artificial neural network vs recurrent neural network controller with positive output super lift Luo converter

In today’s world, the need for clean energy is crucial. Historically, Renewable energy sources like hydropower, wind, and solar offer sustainable solutions. Photovoltaic (PV) systems convert sunlight into electricity using semiconductor PV cells, which have been efficient for over 30 years. PV cell efficiency depends on irradiance (solar photon intensity) and temperature. Higher irradiance increases efficiency, while higher temperatures decrease it. PV systems, despite low voltage outputs, can be optimized using DC-DC Positive Output Super Lift Luo converters to match load requirements, enhancing system efficiency. Solar irradiance varies throughout the day, affecting PV cell output. Maximum Power Point Trackers (MPPTs) adjust the system's operating point to maintain peak efficiency. This study focuses on designing AI controllers to manage MPPT. We compare the performance of Artificial Neural Networks (ANN) and Recurrent Neural Networks (RNN) using three datasets. The goal is to identify the most efficient AI controller for optimizing solar energy systems.

Helical Micropillar Processed by One-Step 3D Printing for Solar Thermal Conversion.

Solar thermal utilization has broad applications in a variety of fields. Currently, maximizing the photo-thermal conversion efficiency remains a research hotspot in this field. The exquisite plant structures in nature have greatly inspired human structural design across many domains. In this work, inspired by the photosynthesis of helical grass, a HM type solar absorber made in graphene-based composite sheets is used for solar thermal conversion. The unique design promoted more effective solar energy into thermal energy through multiple reflections and scattering of solar photons. Notably, the Helical Micropillar (HM) is fabricated using a one-step projection 3D printing process based on a special 3D helical beam. As a result, the solar absorber's absorbance value can reach 0.83 in the 400-2500nm range, and the surface temperature increased by ≈128.3% relative to the original temperature. The temperature rise rate of the solar absorber reached 22.4°Cmin-1, demonstrating the significant potential of the HM in practical applications of solar thermal energy collection and utilization.

The Pigment World: Life's Origins as Photon-Dissipating Pigments.

Many of the fundamental molecules of life share extraordinary pigment-like optical properties in the long-wavelength UV-C spectral region. These include strong photon absorption and rapid (sub-pico-second) dissipation of the induced electronic excitation energy into heat through peaked conical intersections. These properties have been attributed to a "natural selection" of molecules resistant to the dangerous UV-C light incident on Earth's surface during the Archean. In contrast, the "thermodynamic dissipation theory for the origin of life" argues that, far from being detrimental, UV-C light was, in fact, the thermodynamic potential driving the dissipative structuring of life at its origin. The optical properties were thus the thermodynamic "design goals" of microscopic dissipative structuring of organic UV-C pigments, today known as the "fundamental molecules of life", from common precursors under this light. This "UV-C Pigment World" evolved towards greater solar photon dissipation through more complex dissipative structuring pathways, eventually producing visible pigments to dissipate less energetic, but higher intensity, visible photons up to wavelengths of the "red edge". The propagation and dispersal of organic pigments, catalyzed by animals, and their coupling with abiotic dissipative processes, such as the water cycle, culminated in the apex photon dissipative structure, today's biosphere.

Chirped Laser Pulse Control of Vibronic Wavepackets and Energy Transfer in Phycocyanin 645.

Photosynthetic organisms use light-harvesting complexes to increase the spectrum of light that they absorb from solar photons. Recent ultrafast spectroscopic studies have revealed that efficient (sub-ps) energy transfer is mediated by vibronic coherence in the phycobiliprotein phycocyanin 645 (PC645). Here, we report studies that employ broadband pump-probe spectroscopy with linearly chirped excitation pulses to further investigate the relationship between vibronic state preparation and energy transfer dynamics in PC645. Negatively chirped pulse excitation is found to enhance wavepackets of a high-frequency mode (1580 cm-1) and increase the rate of downhill energy transfer, while on the other hand, positively chirped pulses suppress these oscillatory features and decrease this rate. Model calculations incorporating the influence of the chirped pump pulse are used to understand its effect on initial state preparation. These results provide mechanistic insight into how the overall nonequilibrium rate of energy transfer is influenced by initial state preparation.

SCAPS 1D based study of hole and electron transfer layers to improve MoS2–ZrS2 solar cell efficiency

In the realm of photovoltaic applications, scientists and technocrats are striving to maximize the solar cell input photon energy conversion to electricity. However, achieving optimal cell efficiency requires significant time and energy investment for each variation and optimization. To overcome this issue authors simulated and studied the fabricated cell for optimizing conditions, which can save time and efforts for the relatively better outcomes. The family of transition metal chalcogenides holds promise as a material that yield improved outcomes in optoelectronic applications, particularly in photovoltaics. These materials are employed in experimental investigations aimed at enhancing solar cell parameters, resulting in the development of the FTO/ZnO/ZrS2/MoS2/CuO/Au composite cell. Numerical simulations utilizing SCAPS-1D software is conducted, focusing on the significance of CuO as a hole transport layer (HTL), and ZnO as an electron transport layer (ETL). The investigation examines into the impact of various factors, including thickness, bandgap, and carrier densities for both HTL and ETL, on fundamental solar cell parameters. The study indicates that device parameters are influenced by factors such as recombination rate, photogenerated current, charge carrier length, and built-in-voltage. Optimized parameters for HTL, including thickness, bandgap, and carrier concentration, are determined to be 0⋅35 μm, 1⋅2 eV, and 1⋅0 × 1020 cm–3, respectively. For ETL, the optimized parameters are found to be 0⋅05 μm, 3⋅1 eV, and 1⋅0 × 1018 cm–3, respectively. With these optimized parameters, the efficiency of the solar cell reached 20⋅64%, accompanied by open circuit voltage, short circuit current density, and fill factor values of 0.836 V, 36.021 mA⋅cm–2, and 68⋅54%, respectively. The simulated results indicate that addition of two extra layers and the use of efficient binary materials in heterojunction formation can effectively enhance device parameters, offering advantages such as low-cost and large-scale fabrication.

Prospects on the detection of solar dark photons by the International Axion Observatory

Dark (hidden) photons are widely recognised as well motivated candidates for physics beyond the standard model, and have been invoked for the solution of several outstanding problems, including to account for the dark matter in the universe. In this paper, we consider a simple model for dark photons, which is coupled to ordinary matter only through kinetic mixing with ordinary photons. Within this framework, we calculate the flux of solar dark photons on Earth and revise the potential to detect it with the next generation of axion helioscopes, particularly with the International AXion Observatory (IAXO). This paper extends on previous theoretical analyses in two main ways. Firstly, it includes a more complete analysis of the possible sources of dark photons from the sun, including the contribution of the solar magnetic field and of nuclear processes, and secondly it includes predictions on the parameter space accessible in the gas-filled phase of IAXO.

Effects of an Explicit Time-dependent Radiation Pressure Force on Trajectories of Primary Neutral Hydrogen in the Heliosphere

Radiation pressure exerted by solar photon output is salient to the motion of primary neutral hydrogen atoms streaming into the inner heliosphere directly from the local interstellar medium. The action of a time-dependent radiation pressure force, when coupled with the usual gravitational force, changes the characteristic velocities, and therefore energies, of the atoms when they reach regions in which explorer probes are present. A study is presented that uses a 2D code to backtrace neutral hydrogen trajectories from representative target points located 1 au from the Sun. It makes use of both a radiation pressure function and a function for the photoionization rate at 1 au that both oscillate with time based on measurements over a typical solar cycle, as well as a time-independent charge exchange ionization rate at 1 au. Assuming a Maxwellian distribution in the distant upwind direction, phase space data is calculated at the target points, at different moments in time. The dependence of the force on the radial particle velocity has been omitted in the analysis, such that the emphasis is on the effects of the global solar UV intensity variations through the solar cycle. This process allows for the analysis of direct and indirect Maxwellian components through time and space in the time-dependent force environment. Additionally, pseudo-bound orbits caused by energy losses associated with this force environment are observed, and their properties are evaluated with the aim of determining their effects on potential measurements by explorer probes.

Thermal-structural and prestressed modal analyses for a solar sail with nonlinear shape memory alloy spring

The objective of this research is to forecast the impact of alternating non-uniform temperature distributions on the deformation and internal stress within the thin film of a solar photon sail, as well as to assess how stress variations affect the sail’s characteristics. To maintain the internal stress amplitude within the film during extreme temperature fluctuations, the solar sail employs an innovative pre-tensioning technique utilizing shape memory alloy (SMA) springs. A thermal-structural model is formulated specifically for a hexagonal solar sail. Subsequently, thermal-structural analyses are conducted to quantify deformations and stresses within the sail during its operation on the Earth-Moon L1 halo orbit. Incorporating the prestress factor, the out-of-plane deflection of the film under solar pressure is computed. Furthermore, prestressed modal analyses are performed to determine mode shapes and natural frequencies, taking into account both the prestress and the solar pressure acting on the film. Finally, numerical results are used to compare the performance of the solar sail in hot and cold environments.

Exploring ionospheric dynamics: a comprehensive analysis of GNSS TEC estimations during the solar phases using linear function model

Abstract The modeling and forecasting of Total Electron Content (TEC) play a major role in influencing signals from satellite-based navigation systems and impact the performance of diverse satellite-dependent technologies. The intensity of solar ionizing radiation and the state of geomagnetic field activity influence the Global Navigation Satellite System (GNSS)-TEC. This paper uses a Linear TEC Function (LTF) climatology model to understand ionospheric behavior under solar and geomagnetic activities that cause variations in the electron distribution of the ionosphere medium. The LTF model integrates representations of solar EUV photon (MgII) and geomagnetic (SYMH) activities, incorporating solar-modulated oscillations (periodic variations) at four seasonal cycles and a linear trend. The LTF model examined the time series of GPS-TEC at a location (geographic 34.95° N, 134.05° E) with a time resolution of 1 h, from 1997 to 2016, covering solar cycles 23 and 24. The Root Mean Square Deviation (RMSD) and correlation coefficient between the GNSS-TEC and model TEC (LTF) was 5.30 TECU and 95 %. The results indicate that solar components, as well as annual and semi-annual variations, have a significant impact on the daily average TEC. Solar activity appears to be the predominant determining factor of TEC during the solar phases of cycles 23 and 24. In contrast, periodic influences primarily outline TEC during periods characterized by minimal solar activity. The geomagnetic component presents an increased influence, particularly during storm periods. The model demonstrates superior performance in Total TEC modeling compared to other state-of-the-art approaches.

Experimental study on the radiation-induced destruction of organic compounds on the surface of the Moon

Volatile organic molecules and a complex organic refractory material were detected on the Moon and on lunar samples. The Moon’s surface is exposed to a continuous flux of solar UV photons and fast ions, e.g. galactic cosmic rays (GCRs), solar wind (SW), and solar energetic particles (SEPs), that modify the physical and chemical properties of surface materials, thus challenging the survival of organic compounds. With this in mind, the aim of this work is to estimate the lifetime of organic compounds on the Moon’s surface under processing by energetic particles. We performed laboratory experiments to measure the destruction cross section of selected organic compounds, namely methane (CH4), formamide (NH2CHO), and an organic refractory residue, under simulated Moon conditions. Volatile species were deposited at low temperature (17 - 18 K) and irradiated with energetic ions (200 keV) in an ultra-high vacuum chamber. The organic refractory residue was produced after warming up of a CO:CH4 ice mixture irradiated with 200 keV H+ at 18 K. All the samples were analyzed in situ by infrared transmission spectroscopy. We found that destruction cross sections are strongly affected (up to one order of magnitude) by the dilution of a given organic in an inert matrix. Among the selected samples, organic refractory residues are the most resistant to radiation. We estimated the lifetime of organic compounds on the surface of the Moon by calculating the dose rate due to GCRs and SEPs at the Moon’s orbit and by using the experimental cross section values. Taking into account impact gardening, we also estimated the fraction of surviving organic material as a function of depth. Our results are compatible with the detection of CH4 in the LCROSS eject plume originating from layers deeper than about 0.7 m at the Moon’s South Pole and with the identification of complex organic material in lunar samples collected by Apollo 17 mission.

Probing Lorentz Invariance Violation with Absorption of Astrophysical γ-Rays by Solar Photons

We compute in detail the absorption optical depth for astrophysical γ-ray photons interacting with solar photons to produce electron–positron pairs. This effect is greatest for γ-ray sources at small angular distances from the Sun, reaching optical depths as high as τ γ γ ∼ 10−2. We also calculate this effect including modifications to the absorption cross-section threshold from subluminal Lorentz invariance violation (LIV). We show for the first time that subluminal LIV can lead to increases or decreases in τ γ γ compared to the non-LIV case. We show that, at least in principle, LIV can be probed with this effect with observations of γ-ray sources near the Sun at ≳20 TeV by HAWC or LHAASO, although a measurement will be extremely difficult due to the small size of the effect.

A Missing Piece of the E‐Region Puzzle: High‐Resolution Photoionization Cross Sections and Solar Irradiances in Models

AbstractMost ionospheric models cannot sufficiently reproduce the observed electron density profiles in the E‐region ionosphere, since they usually underestimate electron densities and do not match the profile shape. Mitigation of these issues is often addressed by increasing the solar soft X‐ray flux which is ineffective for resolving data‐model discrepancies. We show that low‐resolution cross sections and solar spectral irradiances fail to preserve structure within the data, which considerably impacts radiative processes in the E‐region, and are largely responsible for the discrepancies between observations and simulations. To resolve data‐model inconsistencies, we utilize new high‐resolution (0.001 nm) atomic oxygen (O) and molecular nitrogen (N2) cross sections and solar spectral irradiances, which contain autoionization and narrow rotational lines that allow solar photons to reach lower altitudes and increase the photoelectron flux. This work improves upon Meier et al. (2007, https://doi.org/10.1029/2006gl028484) by additionally incorporating high‐resolution N2 photoionization and photoabsorption cross sections in model calculations. Model results with the new inputs show increased O+ production rates of over 500%, larger than those of Meier et al. (2007, https://doi.org/10.1029/2006gl028484) and total ion production rates of over 125%, while production rates decrease by ∼15% in the E‐region in comparison to the results obtained using the cross section compilation from Conway (1988, https://apps.dtic.mil/sti/pdfs/ADA193866.pdf). Low‐resolution molecular oxygen (O2) cross sections from the Conway compilation are utilized for all input cases and indicate that is a dominant contributor to the total ion production rate in the E‐region. Specifically, the photoionization contributed from longer wavelengths is a main contributor at ∼120 km.

Comparison of the SRP spherical model between LEO and GEO satellites

Solar Radiation Pressure (SRP) is a phenomenon caused by the pressure exerted by solar photons on a satellite’s surface when it is exposed to sunlight. It is a form of radiation force and can significantly impact the motion and behaviour of satellites in space. SRP influences a satellite’s orbit by causing changes in its semimajor axis, eccentricity, inclination, argument of perigee, right ascension of the ascending node, and mean anomaly. SRP models are used to simulate the effects of solar radiation pressure on satellites. These models are essential for accurately predicting satellite trajectories and orbital behaviour. There are several types of SRP models, such as spherical model, flat model, box-wing model, faceted model, and analytical SRP models. This research focuses on Telkom 1 and LAPAN A1 satellites, both belonging to Indonesia and positioned in Geostationary Earth Orbit (GEO) and Low Earth Orbit (LEO) orbits, respectively. The study aims to find a comparison of the effects of SRP spherical model on LEO and GEO satellites. Our modelling shows that the semimajor axis and eccentricity are sensitive to SRP, while the inclination and right ascension of the ascending node are not significantly affected. Comparing the effects of SRP on LEO and GEO satellites, we concluded that both LEO and GEO orbit experience the most significant fluctuations in January (perihelion), likely due to the influence of solar radiation pressure.

Effects of Heliolatitudinal Anisotropy of Solar Far-ultraviolet/Extreme-ultraviolet Emissions on Lyα Helioglow

We present a study of the influence of solar UV anisotropy on the heliospheric backscatter helioglow generated by resonant scattering of solar Lyα photons on interstellar hydrogen atoms around the Sun. Simulations based on the WawHelioGlow model suggest that the response of the helioglow pole-to-ecliptic ratio to the anisotropy is linear, but 15% of the anisotropy (polar darkening) generates 30%–40% change in the ratio in the solar minimum and 15%–20% in the solar maximum. We attribute this difference to an interplay between the solar UV anisotropy and the latitudinal structure of the solar wind in solar minima. The solar UV anisotropy also increases the helioglow intensity from the downwind direction by 5%–10%, due to the influence of the anisotropy on the ionization losses and trajectories of atoms passing by the Sun in polar regions. Consequently, midlatitude regions (in the heliographic and ecliptic coordinates) are least affected by the UV anisotropy. By comparison of the simulation results with observations of the Solar and Heliospheric Observatory/SWAN satellite instrument, we derive the day-by-day time evolution of the solar Lyα anisotropy for the north and south poles over two solar cycles from 1996 to 2022. The inferred anisotropy is ∼5%–10% in solar minima and ∼15%–25% in solar maxima, the northern anisotropy being stronger than the southern one. Our study suggests that in solar minima a highly structured solar wind is associated with relatively small solar UV anisotropy, while in solar maxima the solar wind is more isotropic but a substantial solar UV anisotropy appears.

Planar semiconductor junctions with robust driving forces synergistically orienting direct water splitting

Pure water splitting by charged semiconductors and solar photons to concurrently generate H2 and O2 molecules has gained notable attention due to worldwide clean energy generation and storage. Despite significant advancements, challenges facing severe carrier recombination and sluggish electron transport continue to hinder the intrinsic efficiency of water splitting. Here, we fabricate two-dimensional graphitic carbon nitride-hybridized sulfur thionic polymorphs (CN/S100/S010 junctions) by incorporating photoactive semiconductors within lateral nanosheets. As a result, the charge rectification effect within the coplanar graphitic carbon nitride/S100/S010 junctions is induced by well-designed driving forces: favorable band offsets and cascade polarized surface work functions. During the water splitting process, the photogenerated electrons are sequentially transferred from graphitic carbon nitride to element semiconductor sulfur {100} and subsequently oriented to sulfur {010} facets. This unique behavior of charge migration within CN/S100/S010 photocatalysts contributes to impressive rates of H2 and O2 production, reaching 740 and 363 µmol g−1·h−1, respectively, nearly 13-fold higher than that of the parent carbon nitride. Comprehensive spectroscopic and theoretical analyses confirm the formation of CN/S100/S010 hierarchies with long-lived charge carriers during hydrogen energy production. This work introduces novel avenues for automatically orienting photogenerated carriers and holds promising prospects for clean energy production.

Ambient solid-state triplet-triplet annihilation upconversion in ureasil organic-inorganic hybrid hosts.

Triplet-triplet-annihilation upconversion (TTA-UC) has attracted significant attention as an approach to harvest low energy solar photons that cannot be captured by conventional photovoltaic devices. However, device integration requires the design of solid-state TTA-UC materials that combine high upconversion efficiency with long term stability. Herein, we report an efficient solid-state TTA-UC system based on organic-inorganic hybrid polymers known as ureasils as hosts for the archetypal sensitiser/emitter pair of palladium(ii) octaethylporphyrin and diphenylanthracene. The role of the ureasil structure on the TTA-UC performance was probed by varying the branching and molecular weight of the organic precursor to tune the structural, mechanical, and thermal properties. Solid-state green-to-blue UC quantum yields of up to 1.86% were observed under ambient conditions. Notably, depending on the ureasil structure, UC emission could be retained for >70 days without any special treatment, including deoxygenation. Detailed analysis of the structure-function trends revealed that while a low glass transition temperature is required to promote TTA-UC molecular collisions, a higher inorganic content is the primary factor that determines the UC efficiency and stability, due to the inherent oxygen barrier provided by the silica nanodomains.