Cryogenic thermal control coatings represent a significant advancement over existing coatings limited to high reflectance in the 0.2-2.5 μm solar spectrum range, being able to reflect 96.6% of solar irradiance and to reach about 145 K equilibrium temperature, offering transformative potential for deep-space exploration, remote sensing, and other cryogenic applications. To achieve the cryogenic temperature further lower than 100 K in space, the peculiar optical property to reflect 99.9% of solar irradiance becomes necessary, which can be realized by an ultra-broadband reflectance from 0.2 to 8 μm. Here, we propose a bi-layer meta-composite comprising two distinct photonic random media, where rationally designed scatterer sizes selectively target short- and long-wavelength solar irradiance. By matching the scattering peak regimes, the meta-composite achieves a weighted solar reflectance of 97.3% over an ultrabroad 0.2-8 μm region. In the home-built deep-space simulator, the bi-layer meta-composite maintains an equilibrium temperature of 145 K, superior to existing coatings designed for room-temperature thermal control. Ground simulated irradiation tests further demonstrate exceptional optical stability under charged particles and atomic oxygen irradiations, with degradation of less than 1.5%. Moreover, the meta-composite retains optical properties comparable to existing coatings even after long-term ultraviolet irradiation. This work not only highlights the viability of photonic random meta-composites for cryogenic thermal control but also introduces a scattering regime matching strategy to broaden the spectral selectivity of disordered photonic systems.

Most widely-studied semiconductor catalysts have low efficiency in utilizing near-infrared (NIR) light in the solar spectrum, while also facing major issues such as slow charge-carrier migration rate and lack of active sites that limit photocatalytic performance. Here, a new strategy to promote the solar-light driven photocatalytic activity of ZnIn2S4 was proposed by introducing Rh single atom (SAs) into CeO2:Yb,Er/ZnIn2S4 with photo-thermo-electric effects. The introduction of Rh SAs into ZnIn2S4 effectively suppresses charge recombination, and improves reaction rate through photo-thermal effect. CeO2:Yb, Er converts NIR light into visible light via up-conversion photo-optical processes and generates high-energy electrons via two-photon photo-electronic process, both of which can activate ZnIn2S4. Large contact area and strong interface electric field between CeO2 and ZnIn2S4 enhance photo-electric conversion efficiency. The CeO2:Yb,Er/Rh-ZnIn2S4 exhibits a hydrogen production rate of up to 99.68 mmol·g-1·h-1 at 10°C and 148.06 mmol·g-1·h-1 with non-temperature-controlled conditions. Under mild conditions, the photocatalysts can convert glucose into high-value-added chemicals (e.g., arabinose) while simultaneously generating hydrogen. This work provides a new strategy to improve NIR light utilization efficiency and enhance charge-carrier separation capability through photo-thermo-electric effects, promoting the production of green hydrogen and biomass conversion into high-value-added chemicals.

The United States Army Institute for Surgical Research conducted an analysis of 3 prototype sensor suites; all candidates were designed to passively document care delivery in tactical combat casualty care environments. This study aims to ensure sensor suites remain resilient and adaptive in complex battlefield environments. This research effort conducts a systematic comparative assessment of prototype solutions. The assessment methodology prioritized functionality, usability, and performance. The assessment consisted of three phases: (1) tabletop evaluations, (2) simulated use testing, and (3) a sensor suite rodeo simulation event. The second and third phases included human participants leveraging the technology prototypes in hyperrealistic tactical combat casualty care simulation environments. Additionally, the third phase allowed the researchers to assess the performance of each prototype in a range of operational environmental lighting conditions. During the tabletop evaluation phase, all 3 prototype sensor suite solutions demonstrated acceptable results (≥1) in the technical specification assessment. The 2-part heuristic analysis revealed variability, where the least complex configurations received the highest assessment scores. To capture and record raw data, scores ranged from 44.6 to 87 on a 100-point scale. To offload and export the raw data, scores ranged from 22.9 to 87.5 on a 100-point scale. During simulated user testing, all 3 sensor suites achieved passing quantitative scores (≥60); the system usability scores (SUS) ranged from 60 to 85 on a 100-point scale. More complex technology configurations received higher usability scores. From a qualitative perspective, vital sign monitor latency display issues led to reliability concerns. All 3 prototypes successfully generated raw data; the individual outputs ranged from 0.06 to 0.13 GB/minute. During the sensor suite rodeo simulation event, all 3 sensor suites achieved passing quantitative scores (≥60); the SUS ranged from 66.7 to 86.7 on a 100-point scale; the most complex technology prototype configuration scored higher. Qualitative findings identified data transfer issues with large file sizes and pairing issues with vital sign monitors. All 3 prototypes successfully generated raw data; the individual outputs varied (ranging from 0.012 to 0.24 GB/min) based on the environmental lighting conditions (full sun, indoor lighting, and low light). However, from a data quality perspective, only 1 camera component produced viable video data in all 3 environments. The comparative assessment revealed opportunities to combine the strengths of both approaches in a next-generation implementation. This preliminary assessment was constrained by several factors: (1) effective tracking of consumable medical supplies, (2) advancement of artificial intelligence algorithms to process the raw data, and (3) ability to manage multiple casualties or patients. Follow-on evaluations are needed to address these limitations. This systematic, 3-part methodology evaluates early-stage sensor suite prototypes and provides a reproducible framework for advancing battlefield medical technologies.

Copper and zinc oxides (CuO, Cu2O, ZnO) are semiconductors with p-type and n-type conductivity, respectively, which have attracted attention as perspective materials for the research and development of p-n junction-based devices. Their low cost and abundance are ideal for applications in electronics and solar radiation sensing and harvesting. Most research involving these materials has been focused on UV-VIS photodetectors and solar cells, as well as p-n junction-based diodes. However, less attention has been paid to thermoelectric applications or the detection/energy harvesting of infrared radiation, which constitutes a significant part of the solar spectrum. In this work, electrical properties and the unbiased response to infrared radiation of CuO-Cu2O-ZnO heterojunction nanowires are studied. The vertically arranged CuO-Cu2O-ZnO nanowire arrays were synthesized directly on copper substrates using a combined thermal oxidation/thermal evaporation method and studied in-situ inside a scanning electron microscope using nanomanipulation techniques. The nanowires were found to exhibit diode-like behavior, indicating the presence of a p-n junction. Furthermore, a pronounced unbiased response to infrared radiation was observed and attributed to the photo-thermoelectrical effect. The estimated Seebeck coefficient, power factor, and responsivity of the CuO-Cu2O-ZnO heterojunction nanowires were 120 µV/K, 18 nW/mK2, and 150mA/W respectively. The absorbance capabilities of the material widen the potential for applications in effective harvesting of the full spectrum of solar energy. Additionally, the material furthers the development of nano-power generators operating at low-temperature differences of a few degrees Celsius, which may be favorable for a wide range of applications, like wearable electronics, Internet-of-Things, environmental and health sensors.

Dual-vacancy engineering in self-sacrificial Bi4O5Br2/Bi13S18I2 step-scheme heterojunction boosts photothermal photocatalytic removal of hexavalent chromium and tetracycline.

IO2- and IO2 have been detected in the atmosphere and suggested as reactive intermediates in the destruction of ozone. Here, photoelectron action spectroscopy provides evidence for a vibrational progression of anion resonances, characterized by a vibrational frequency of ∼0.03 eV, originating from a weakly bound (close to the photodetachment threshold) electronically excited state of IO2-. Photoelectron spectroscopy of IO2- at visible wavelengths shows indirect electron loss processes, likely autodetachment of the vibrational resonances leading to internally excited IO2, alongside direct detachment. Given that the excited state has a vertical excitation energy in the visible portion of the solar spectrum, it is likely that photoexcitation of IO2- is occurring in the atmosphere, providing a new route for the formation of electrons and internally excited IO2.

The process of photosynthetic carbon fixation by microalgae represents a significant pathway for achieving green and sustainable carbon capture. However, the mismatch between the microalgal pigments' absorption spectrum and the solar spectrum severely limits light conversion efficiency. To mitigate this limitation, NaErF4:Tm(0.5%)@NaYF4 upconversion nanoparticles were employed to facilitate the conversion of near-infrared (NIR) photons into photosynthetically active radiation. This extended the usable spectral range of microalgae beyond the conventional photosynthetically active region of 400-700 nm by converting near-infrared photons into red light that can be used for photosynthesis, thereby enhancing light conversion efficiency. The biohybrid system of microalgae integrating NaErF4:Tm(0.5%)@NaYF4 exhibited a 157.41% enhancement in light absorption in the 950-1000 nm region and a 27.98% increase in the 1500-1600 nm region, accompanied by red emission at 650-700 nm that can be efficiently utilized by microalgae. The maximum electron transport rate (ETRmax) of microalgae increased by 20.18%, while ATP and NADPH contents rose by 47.06% and 19.82%, respectively, and the maximum CO2 fixation rate increased by 94.31%. Consequently, compared with the control group, the density of the microalgal biomass rose by 19.67%, while the light conversion efficiency increased by 34.99% to reach 8.4%. This work develops a biohybrid system that enhances NIR light harvesting and photosynthetic carbon fixation, elucidates the role of NIR photon upconversion in regulating photosynthetic electron transport and metabolism in microalgae, and thereby provides a pathway for efficient microalgal photosynthetic carbon capture.

Herein, an ‘antenna-mediated’ singlet fission (SF) molecular platform is reported, in which a phenyldiketopyrrolopyrrole (PDPP) chromophore with strong visible-light absorption is strategically integrated into TIPS-pentacene (P) dimers as a conjugated bridge to overcome the intrinsically weak absorption of conventional P-based SF systems. Owing to the complementary absorption and emission characteristics of PDPP and P, the resulting conjugates enable highly efficient intramolecular Förster resonance energy transfer (FRET) from PDPP to P, followed by intramolecular SF of the P dimer. Upon selective excitation of the PDPP antenna, ultrafast and nearly unity FRET occurs on a picosecond timescale, populating the singlet excited state of P and triggering SF with rates identical to those observed under direct P excitation. This demonstrates that antenna-mediated excitation fully preserves the intrinsic SF dynamics while extending excitation across the entire visible solar spectrum. The exceptional energy-transfer efficiency is rationalized by a large orientation factor, substantial spectral overlap, and the high fluorescence quantum yield of PDPP. Moreover, solvent polarity provides an external handle to modulate the spectral overlap and thereby tune both the FRET and SF rate constant, without requiring chemical modification of the molecular framework. Overall, this work establishes an antenna-enabled strategy for broadband solar-energy harvesting coupled to efficient SF, offering a general molecular design concept for next-generation SF materials with enhanced solar utilization efficiency.

Advanced radiative cooling textiles represent a promising avenue for improving human thermal comfort in the face of global warming. However, their limited sweat evaporation capacity and low thermal conductivity significantly reduce the cooling efficiency, particularly in hot outdoor climates. Herein, a novel transpiration-inspired metafabric that integrates precise solar spectrum regulation, a high heat conduction pathway, and splendid moisture-wicking capacity was presented through multi-scale electrospun structural design. The gradient micro-nano porous metafabric can broadly scatter the solar spectrum while establishing a gradual refractive index transition to enhance mid-infrared absorption. The solar reflectivity and infrared emissivity of the metafabric reached 99.7% and 93.3%, respectively, inducing a cooling effect of 10.2°C and net cooling power (Pnet) of 110.1W/m2. Meanwhile, the metafabric with a gradual wettability gradient and capillary force gradient exhibited a high one-way transport index (R) of 1330.7% and a reverse breakthrough pressure of 15.0cm H2O, effectively preventing liquid pinning and back penetration. What's more, the coupled strategy of thermal radiation, conduction, and evaporation resulted in a temperature drop of 20.2°C in the sweaty state. The metafabric also demonstrated superb mechanical robustness, breathability, and washability. The work may offer a scalable and energy-efficient strategy for advanced thermal and moisture management textiles.

Accurately calculating photovoltaic (PV) module efficiency is a key step in solar energy applications. As PV efficiency is influenced by the spatiotemporal variability of the solar spectrum, it is essential to employ local spectra as a replacement for the single AM1.5 G standard spectrum to assess PV modules’ performance. Focusing on the PV-relevant spectral range (280–1400 nm), a total of 186,357 valid solar spectra measured in Beijing over one year were compiled, and a data-driven approach was used to establish a set of five local reference (LR) spectra. An autoencoder was used to reduce spectral dimensionality to five, and k-means clustering (k = 5) was applied to group the spectra, with the cluster-centroid spectra adopted as the LR spectra. Cluster 1 deviated most from AM1.5 G in band-integrated irradiance, with a maximum difference of 77.14%. APE increased from 1.713 eV for AM1.5 G to 1.81 eV for Cluster 5, corresponding to a maximum relative change of 5.66% among the five LR spectra. For common PV materials with different bandgaps, the spectral factor under the LR spectra versus AM1.5 G differed by up to 9.6%, and AM1.5 G tended to overestimate PV efficiency for most of the time in Beijing. The proposed LR spectra provide a practical regional spectral baseline for PV performance evaluation. • Long-term spectra measurements were conducted to capture spectral characteristics. • The significant difference between the spectra in Beijing and AM1.5 G was detected. • Local reference spectra were generated by data-driven techniques. • Most PV modules’ performance is overestimated by the AM1.5 G spectrum in Beijing. • APE can’t characterize the impact of the spectrum on PV modules alone.

Dual-mode Upconversion and Downconversion in Yb3+/Er3+ Co-doped BiOCl for enhanced solar spectrum harvesting

Inkjet printing technology was successfully applied to flexible substrates to produce, for the first time, >10% efficient flexible kesterite solar cells, which also retained over 90% of their initial performance after 500 bending cycles. Cu 2 ZnSn(S,Se) 4 (CZTSSe or kesterite) is an emerging inorganic light absorber with a bandgap of 1.0–1.5 eV, ideal for efficient solar spectrum harvesting. This material can be grown on both rigid and flexible substrates, standing as one of the most promising candidates for Integrated Photovoltaics. Solution-based methods are currently the best choice for CZTSSe synthesis, relying on the deposition of multiple layers. The most widely used techniques are blade coating, spray pyrolysis, dip coating, and spin coating, with the latter achieving the highest efficiencies. However, this technology’s small-area limitations and large precursor waste still hinder the kesterite solar cells’ scalability. In contrast, drop-on-demand inkjet printing is a promising and industrially appealing solution-based technique suitable for processing large areas. To date, it has been tested in a few cases, yielding encouraging results with rigid solar devices; however, it has never been used to fabricate flexible CZTSSe solar cells. In this work, we report on the first-time realization of inkjet-printed flexible kesterite solar cells. The resulting devices exhibit an efficiency enhancement over our spin-coated references, driven by improved film crystallinity, reduced shunting, and enhanced fill factor. The inkjet-printed flexible champion device achieved an efficiency of 10.4%, outperforming our spin-coated reference counterpart. Structural, morphological, and optoelectronic analyses confirm the superior quality of the inkjet-deposited absorber. This scalable, solution-based approach establishes a pathway for the roll-to-roll fabrication of earth-abundant, lightweight kesterite photovoltaics for next-generation, integrated, and flexible photovoltaic applications, a key factor for the advancement of kesterite materials in the photovoltaic sector.

Solar-driven environments disinfection via optimized S-scheme Bi2MoO6/KNbO3 heterostructures: Decoupling surface redox reactions and band alignment effects.

Grid stability is of prime importance for grid-tied solar power systems as they are prone to power quality issues caused by the varying intensity of sun radiation and grid disturbances. To maintain grid stability, various PV power tracking algorithms have been developed. However, classical power tracking models often fail to maintain grid stability and sustain required power reserves under real-time variations in grid conditions and solar generation. To address this limitation, a Dynamic Reserve Power Point Tracking (DRPPT) control algorithm is proposed to ensure grid stability by dynamically adjusting reserve power. By continuously monitoring the PV array and grid conditions, the proposed controller determines the dynamic solar reserve power and accordingly selects the suitable operating mode. The operating point of PV array is then regulated by Flexible Power Point Tracking (FPPT) technique, which performs fine-tuning of the reference voltage followed by grid injection. By combining FPPT and Maximum Power Point Tracking (MPPT) functionalities, the proposed DRPPT controller maintains optimal reserve levels, ensuring the grid can rapidly respond to sudden changes in power supply or demand while meeting customer requirements. The proposed model is tested on hardware and simulated on software, and both results show the ability of DRPPT algorithm to handle real-time grid frequency changes and adapt the RPPT operation accordingly to meet grid stability standards. The proposed model has achieved superior THD mitigation, thereby improving grid stability, with 53.75%, 50%, and 7.5% lower THD compared to the conventional RPPT, Global FPPT (GFPPT), and Genetic Algorithm (GA)-based FPPT techniques, respectively.

Nanofluid-based spectral filtering offers a promising approach to enhance photovoltaic/thermal (PV/T) system performance by utilizing the full solar spectrum. However, system optimization remains challenging due to complex nonlinear relationships between nanofluid parameters and overall performance. This study develops a prediction-optimization framework integrating deep neural networks (DNN) with genetic algorithms (GA) to accurately analyze multi-parameter interactions and achieve globally optimal designs for nanofluid-based PV/T systems. High-throughput datasets for three nanofluids (Ag, Au, Al) were constructed using theoretical calculations that combined Lorentz–Mie theory, Monte Carlo simulations, and a coupled opto-electro-thermal model. Three machine learning models—DNN, random forest (RF), and decision tree (DT)—were employed to predict key PV/T performance parameters. By synergizing machine learning with GA, a closed-loop prediction-optimization process was established to efficiently identify optimal design parameters. Among the models evaluated, the DNN demonstrated superior performance, achieving prediction accuracies above 99.48% for all three key performance indicators (ηpv, ηth, and MF), significantly outperforming the RF and DT models. Furthermore, SHAP analysis was conducted to quantify the contribution of each input feature and enhance model interpretability. Coupled with the GA, the DNN-GA framework successfully identified globally optimal design parameters for each nanofluid. For instance, for Ag nanofluid, the optimal combination (r = 4.02 nm, h = 9.91 mm, fv = 9.45 × 10−5) yielded a maximum MF value of 1.3603. This work presents an innovative machine learning framework for designing nanofluid filters in PV/T systems, which reduces reliance on iterative experimentation and accelerates the development of high-performance solar energy systems, demonstrating practical value.

Sillen X1 oxychlorides, with the general formula MBiO2Cl (M = Ca, Sr, Ba, Cd), possess unique two-dimensional layered structures featuring self-induced internal electric fields that promote charge separation; however, their wide band gaps limit their applications in the visible portion of the solar spectrum. There is no straightforward cation-doping scheme to tune the optical bandgap into the visible region in Sillen X1 oxyhalides. In this study, we tuned the bandgap of CaBiO2Cl to the visible range by systematically incorporating Fe at the Bi site and synthesizing the samples via a modified gas-solid synthesis method. Substitution of up to 20 mol % Fe in CaBiO2Cl was successful, and the monoclinic symmetry (S.G.: P21/m) was retained. The Fe inclusion caused lattice contraction and local cationic disorder. Fe existed in mixed Fe2+/Fe3+ oxidation states, which led to the oxidation of some amount of Bi3+ to Bi5+. A significant red shift of the band edge with signatures of extended LMCT, intervalence charge transfer, and subtle d-d transitions (due to Fe2+) was observed in UV-visible spectra of the Fe-containing samples. The bandgap narrowed from 3.39-3.52 (CaBiO2Cl) to 2.02 eV (CaBi0.80Fe0.20O2Cl), indicating electronic band structure modification. A similar set of changes was observed when Bi in orthorhombic PbBiO2Cl (S.G.: Cmcm) was substituted with Fe, where the bandgap narrowing was limited (from 2.53-2.71 to 2.04 eV (PbBi0.80Fe0.20O2Cl)). The Fe-substituted samples catalyzed the decoloration of crystal violet dye within 120 min under visible-light irradiation, following pseudo-first-order kinetics. The reactive oxygen species involved in the photocatalytic decoloration were identified. Both catalysts demonstrated recyclability, with their crystal structures remaining intact after use. The demonstrated strategy for tuning the band gaps of the Sillen X1 phases, together with the enhancement of the visible-light photocatalytic properties by efficient charge migration via redox shuttling, qualifies them as sustainable photocatalysts.

Purple bacteria are a diverse group of photosynthetic organisms that can capture and convert light energy with high quantum efficiency across a variety of ecological niches. They absorb light via an array of antenna proteins, primarily light-harvesting complex 2 (LH2), and rapidly transport the energy to the reaction center, where charge separation occurs. LH2 typically consists of eight or nine subunits that each contain three bacteriochlorophyll and one carotenoid. In the marine species Marichromatium (Mch.) purpuratum, the LH2 subunits bind an additional carotenoid, boosting absorbance in the blue where the underwater solar spectrum peaks. In order to accommodate the additional carotenoid, LH2 from Mch. purpuratum consists of only seven subunits, unique among known LH2. Using ultrafast transient absorption (TA) spectroscopy, time-resolved fluorescence, and steady-state techniques, we investigated the effects of these structural differences on the energy transfer dynamics of LH2 from Mch. purpuratum. Our results show, relative to other species, significantly slower rates of energy transfer within LH2 and an excited-state manifold likely to also slow energy transfer between LH2. LH2 from Mch. purpuratum is therefore tuned to match the solar spectrum of its ecological niche, suggesting that the variations in the molecular organization of these antenna proteins may be primarily for optimal light absorption.

Natural dyes offer a promising alternative to synthetic dyes in dye-sensitised solar cells (DSSCs), though their narrow optical absorption limits the efficiency of DSSCs. In present study, five flower samples, five leaf samples, turmeric rhizomes and Basella rubra berries were chosen for initial screening based on their optical absorption characteristics. Following preliminary analysis of visible-region absorption, leaf samples, turmeric rhizomes and Basella rubra berries were selected for further investigation. Chlorophyll, curcumin and anthocyanin pigments were extracted from curry leaves, turmeric rhizomes and Basella rubra berries, respectively. Optical absorption properties of each dye were studied using UV-Visible absorption spectroscopy. The chlorophyll pigment exhibited prominent absorption peaks at 434 nm and 664 nm, while curcumin and anthocyanin showed absorption at 420 nm and 534 nm, respectively. Given that individual dyes absorb only within a specific wavelength range, a co-sensitisation method was adopted to enable the dye to absorb the broad region of the solar spectrum. The bi-pigment blend of chlorophyll and curcumin and the tri-pigment blend of chlorophyll, curcumin and anthocyanin, demonstrated an increase of 159% and 171% respectively, in absorption coefficient, relative to the individual dyes. This enhanced spectral response suggests potential for higher photocurrent density for DSSCs.

Density functional theory (DFT) calculations were employed to investigate quaternary AlGaSi2X6 (X = S, Se, Te) monolayers as two-dimensional semiconductors for photocatalytic and nanoelectronic applications. All three monolayers are predicted to be both dynamically and thermally stable and exhibit indirect band gaps that systematically decrease with increasing chalcogen atomic weight, from 2.79 eV for AlGaSi2S6 to 2.32 eV for AlGaSi2Se6 and 1.12 eV for AlGaSi2Te6. Vacuum-referenced band-edge alignments indicate that AlGaSi2S6 and AlGaSi2Se6 can thermodynamically drive overall water splitting under illumination, whereas AlGaSi2Te6 possesses an insufficient band gap to provide the required photovoltage. Gibbs free-energy profiles further support photoassisted hydrogen and oxygen evolution reactions (HER/OER) on the S- and Se-based monolayers. Moreover, AM1.5G solar spectrum estimates yield solar-to-hydrogen (STH) efficiencies of 3.90% for AlGaSi2S6 and 10.86% for AlGaSi2Se6. Deformation-potential analysis predicts electron-dominated transport with carrier mobilities reaching 1.7 × 103 cm2 V-1 s-1, identifying AlGaSi2Se6 as the most promising overall candidate among these monolayers.

The development of radiative cooling materials through colloidal particle assembly methods represents a promising advancement in thermal management through spectral control. In this work, a cuboid-patterned array of SiO 2 nanorods is proposed to form hyperbolic metamaterials with slow-light waveguiding behavior. The SiO 2 nanorods are vertically assembled into three-dimensional arrays and coated with aluminum-doped zinc oxide (AZO) on their inner surfaces via atomic layer deposition, resulting in effective indefinite dielectric properties—i.e., hyperbolic dispersion—in the infrared regime. Due to the bulk plasmonic resonance of AZO in the infrared range, determined by its doping level, a relative group velocity vg/c as low as one-thousandth can be achieved within the 3–10 µm wavelength range, offering what we believe to be a novel route to enhance infrared emissivity. Furthermore, the fabricated structure exhibits an average emissivity of 84.7% in the 8–13 µm atmospheric window and a low average absorptivity of only 14.6% in the full solar spectrum. Both the experimental results and the electromagnetic simulations confirm the structural potential for daytime radiative cooling.