Absorption Of Sunlight Research Articles

Density functional theory modeling of critical properties of perovskite oxides for water splitting applications

AbstractWater splitting (WS) driven by solar energy is considered as a promising strategy to produce renewable hydrogen from water with minimal environmental impact. Realization of large‐scale hydrogen production by this approach requires cost‐effective, efficient and stable materials to drive the WS reaction. Perovskite oxides have recently attracted widespread attention in WS applications due to their unique structural features, such as compositional and structural flexibility allowing them to achieve desired sunlight absorption capability, precise control of electrocatalytic and redox activity to drive the chemical reaction, tuneable bandgaps and band edges, and earth‐abundance. However, perovskite oxides contain a large family of metal oxides and experimental exploration of novel perovskites without a priori knowledge of their properties could be costly and time‐consuming. First‐principles approaches such as density functional theory (DFT) are a useful and cost‐effective alternative towards this end. In this review, DFT‐based calculations for accurate prediction of the critical properties of ABO3 perovskite oxides relevant to WS processes are surveyed. Structural, electronic, optical, surface, and thermal properties are grouped according to their relevance to photocatalytic (PC), electrochemical (EC), photo‐electrochemical (PEC), and solar thermal water splitting (STWS) processes. The challenges associated with the choice of exchange‐correlation (XC) functional in DFT methods for precise prediction of these properties are discussed and specific XC functionals have been recommended where experimental comparisons are possible.This article is categorized under: Sustainable Energy > Solar Energy Emerging Technologies > Hydrogen and Fuel Cells Emerging Technologies > Materials

Ternary hierarchical structure based solar‐driven evaporator for long‐lasting concentrated brine treatment

AbstractSolar‐driven evaporation has been a promising desalination method for treating concentrated seawater, since it is cost‐effectiveness, simplicity, and environmentally friendly. However, this method faces an unavoidable long‐term problem that the salt generated in the evaporation processes would affect and hinder its evaporation efficiency. Because the salt inevitably crystallizes on the surface of photothermal evaporation materials, and this crystallization process increases with time to impair the material area of the sunlight absorption and evaporation. Here, we show a ternary hierarchical structure based solar‐driven evaporator that reduces the evaporation material surface coverage of the salt to get long‐lasting concentrated brine treatment capacity. This evaporator is constructed by plugging vertically arranged hollow tube arrays across a porous plate. The top, middle, and bottom of the evaporator respectively serve as the salt crystallization site, the evaporation site, and the light absorption site. Meanwhile, the self‐cleaning of the evaporator can be achieved by back diffusion of the crystallized salts. As a result, this efficient and durable evaporator exhibits freshwater production of 10.21 kg/(m2·day) in outdoor experiment in the treatment of the concentrated natural seawater (21.3 wt%).image

Mo-modified (t-m)-ZrO2 with narrowed band gap and strong ability to activate reactants for photocatalytic CO2 reduction

ZrO2 is a promising candidate for photocatalytic CO2 reduction due to its high conduction potential, but it suffers from narrow sunlight absorption range and weak activation ability to reactants. Herein, we explore Mo-modified (t-m)-ZrO2 photocatalysts by a one-step hydrothermal method. As compared to bared ZrO2, their photoresponse extends to the visible light region, being attributed to the impurity band of Mo 4d states embedded in the ZrO2 band gap. Meanwhile, PL and electrochemical tests illustrate that the impurity band also leads to an increase in the carrier separation efficiency. MoO3 nanoparticles and doping Mo in Mo-modified ZrO2 photocatalysts promotes H2O and CO2 activation, respectively. Moreover, in situ FTIR and theoretical calculation revealed that Mo modification is also favorable for the generation of *COOH intermediate and the desorption of CO. As a result, the optimized Mo-modified ZrO2 exhibited a 27.3 μmol·g−1 of the CO yield with ∼100% selectivity, being 13 times higher activity than bared ZrO2. This work provides a guidance for the exploitation of wide bandgap semiconductors in the field of photocatalytic CO2 reduction.

Decreasing the Energy of Evaporation Using Interfacial Water: Is This Useful for Solar Evaporation Efficiency?

Evaporation of water using solar power is an economical and environmentally friendly method for purification of aqueous solutions. It has been suggested that intermediate states can be used to lower the enthalpy of evaporation of water and therefore to increase the efficiency of evaporation that uses absorption of sunlight. However, the relevant quantity is the enthalpy of evaporation from bulk water to bulk vapor, which is fixed for a given temperature and pressure. The formation of an intermediate state does not alter the enthalpy of the overall process.

Interface-Engineered Ni-Coated CdTe Heterojunction Photocathode for Enhanced Photoelectrochemical Hydrogen Evolution

Photoelectrochemical (PEC) water splitting for hydrogen production using the CdTe photocathode has attracted much interest due to its excellent sunlight absorption property and energy band structure. This work presents a study of engineered interfacial energetics of CdTe photocathodes by deposition of CdS, TiO2, and Ni layers. A heterostructure CdTe/CdS/TiO2/Ni photocathode was fabricated by depositing a 100-nm n-type CdS layer on a p-type CdTe surface, with 50 nm TiO2 as a protective layer and a 10 nm Ni layer as a co-catalyst. The CdTe/CdS/TiO2/Ni photocathode exhibits a high photocurrent density (Jph) of 8.16 mA/cm2 at 0 V versus reversible hydrogen electrode (VRHE) and a positive-shifted onset potential (Eonset) of 0.70 VRHE for PEC hydrogen evolution under 100 mW/cm2 AM1.5G illumination. We further demonstrate that the CdTe/CdS p-n junction promotes the separation of photogenerated carriers, the TiO2 layer protects the electrode from corrosion, and the Ni catalyst improves the charge transfer across the electrode/electrolyte interface. This work provides new insights for designing noble metal-free photocathodes toward solar hydrogen development.

A Review on Recent Progress in Preparation of Medium-Temperature Solar-Thermal Nanofluids with Stable Dispersion.

Direct absorption of sunlight and conversion into heat by uniformly dispersed photothermal nanofluids has emerged as a facile way to efficiently harness abundant renewable solar-thermal energy for a variety of heating-related applications. As the key component of the direct absorption solar collectors, solar-thermal nanofluids, however, generally suffer from poor dispersion and tend to aggregate, and the aggregation and precipitation tendency becomes even stronger at elevated temperatures. In this review, we overview recent research efforts and progresses in preparing solar-thermal nanofluids that can be stably and homogeneously dispersed under medium temperatures. We provide detailed description on the dispersion challenges and the governing dispersion mechanisms, and introduce representative dispersion strategies that are applicable to ethylene glycol, oil, ionic liquid, and molten salt-based medium-temperature solar-thermal nanofluids. The applicability and advantages of four categories of stabilization strategies including hydrogen bonding, electrostatic stabilization, steric stabilization, and self-dispersion stabilization in improving the dispersion stability of different type of thermal storage fluids are discussed. Among them, recently emerged self-dispersible nanofluids hold the potential for practical medium-temperature direct absorption solar-thermal energy harvesting. In the end, the exciting research opportunities, on-going research need and possible future research directions are also discussed. It is anticipated that the overview of recent progress in improving dispersion stability of medium-temperature solar-thermal nanofluids can not only stimulate exploration of direct absorption solar-thermal energy harvesting applications, but also provide a promising means to solve the fundamental limiting issue for general nanofluid technologies.

Light absorption of brown carbon and nitrated phenols in aerosols in a city of South Asia: From sources to atmosphere

Nitrated phenols (NPs) are important components of the brown carbon (BrC) aerosols emitted from biomass burning and vehicle emissions. BrC affects the climate through the absorption of sunlight. Previous studies have reported the emission factors and optical properties of BrC from both primary sources and aerosols. However, the contribution of NPs to the absorption of radiation by BrC in aerosols from primary emission sources and ambient aerosols in South Asia, one of the most polluted regions worldwide, is not well known. We systematically investigated the optical properties and components of BrC from emission sources to atmosphere, and found that the major light-absorbing NPs in BrC from biomass burning (e.g., 4-nitrocatechol and methyl-nitrocatechols) were different from those from vehicle emissions (e.g., 2,6-dimethyl-4-nitrophenol and methyl-nitrophenols), which confirmed that the optical properties of BrC depend on the fuel type of the primary source. The contribution of ∑NPs to methanol-soluble brown carbon (MS-BrC) (f∑NPs/MS-BrC (365nm)) in ambient aerosols in Nepal (1–15%) was significantly higher than the value of f∑NPs/MS-BrC (365nm) from primary sources (0.1–2.0%). This indicates that future research should focus on the light absorption properties and climatic effects of NPs in ambient aerosols.

Tuning the oxidation state of titanium dioxide mesoporous film by 1000 eV argon ion beam irradiation

This work proposes the creation of oxygen vacancies on the surface of TiO2 mesoporous film using a 1000 eV argon ion (Ar+) beam. After X-ray photoelectron spectroscopic characterization, the survey spectra of TiO2 nano-particles reveal the presence of oxygen (with chemical state O 1s), titanium (with chemical state Ti 2p), carbon (with chemical state C 1s) and argon (with chemical state Ar 2p) while the concentrations of each chemical states vary with an irradiation time of the Ar+ beam. The acquired Ti 2p spectra show five peaks at high resolution which correspond to Ti4+ 2p3/2, Ti4+ 2p1/2, Ti3+ 2p3/2, Ti3+ 2p1/2, and Ti2+ 2p1/2. The concentrations of Ti2+ and Ti3+ increase with irradiation time while the concentrations of Ti4+ decrease as the irradiation time increases. Three peaks characterize high-resolution spectra of O 1s which correspond to lattice oxygen, oxygen vacancy, and adsorbed oxygen. The peak area of lattice oxygen decreases with irradiation time while that of oxygen vacancies increases with irradiation time which shows the creation of oxygen vacancies at the expense of contaminant removal due to Ar+ exposure. Valence spectra analysis shows an insignificant effect on the valance band as the sample exposure to Ar+ increases. This proposed method of oxygen vacancy creation would facilitate the effective utilization of TiO2-based semiconductors in addressing many photo-catalytic challenges and widening the sunlight absorption capacity of the semiconductor.

The Properties of the CH3NH3PbI3/TiO2 Composite Layer Prepared from PbO-TiO2 Mesoporous Layer under Air Ambience

In TiO2-based perovskite solar cells (PSC), the preparation of the CH3NH3PbI3/TiO2 composite layer is very important, since the morphology of the perovskite adsorbed onto the surface of the TiO2 nanoparticles has decisive significance for the absorption of the incident sunlight and separation of the generated carrier. The traditional two-step spin-coating method for the deposition of CH3NH3PbI3 into the porous mesoporous TiO2 layer usually suffers from filling block problems. In this study, the PbO-TiO2 mesoporous layer was prepared with various ratios of Pb:Ti in the raw materials. Morphological, optical, and element analysis of the prepared thin films indicated that Pb was gradually mixed into the TiO2 mesoporous layer with the increased Pb:Ti ratios. The element distribution characteristics of the optimal thin films showed that the distribution of Pb was uniform throughout the whole TiO2 thin film, which indicates the successful mixing of Pb into the TiO2 electrode layer. Combined with dip coating, the PbO-TiO2 mesoporous layer was prepared into a CH3NH3PbI3/TiO2 composite layer and subsequently to a solar cell device. The prepared solar cell shows a short-circuit photocurrent density of 16.4 mA/cm2, an open-circuit voltage of 900 mV, a fill factor of 61%, and a power conversion efficiency (PCE) of 9.00%. The PCE of the PSC is promoted by nearly 25% when compared with that prepared with the traditional method. The proposed preparation method that combines TiO2 nanoparticle electrode with a mixing and dip coating provides a new effective way to improve the deposition of perovskite into the mesoporous TiO2 layer, which is very helpful for the fabrication of high-efficiency and low-cost PSC.

Carbonized Fast-Growing Bamboo as a Photothermal Device for Efficient Solar Vapor Generation

Solar steam generation is an effective method for solving the freshwater shortage problem. In this study, porous carbonized bamboo (CB) was prepared through high-temperature (700 °C) carbonization under an argon atmosphere for efficient solar steam evaporation. The vertical porous structure of natural bamboo was retained after carbonization for water transportation. Moreover, carbonized bamboo could effectively enhance the degree of graphitization, which is conducive to the absorption of sunlight. According to the results of analysis test, it was obvious that the carbonized bamboo (CB-700) possessed excellent solar energy evaporation potential. The evaporation rate was up to 2.034 kg m–2 h–1 under 1 sun illumination and its solar absorption was averagely 90% in the range of 500–2500 nm. Moreover, the thermal conductivity coefficients of CB-700 and bamboo were 0.1964 and 0.2374 W m–1 K–1, respectively. Owing to this excellent local heat concentration, the surface temperature of CB-700 could achieve 73 °C under 7 sun illumination. Additionally, the material demonstrated an excellent desalting effect on seawater with satisfactory mechanical stability. Thus, the readily available carbonized bamboo can be potentially applied for solar steam generation.

Blackened nanostructured BaTiO3 and heterojunction with g-C3N4 for enhancing photocatalytic and photoelectrochemical properties

In-situ introduction of oxygen-deficiency in traditional semiconductor nano-oxides has been proved to be one of the most effective strategies for enhancing light-harvesting and energy conversion efficiency. This work intends to correlate oxygen vacancy of ferroelectric oxygen carriers with redox properties. The crystalline-BaTiO3 / amorphous-BaTiO3−x / crystalline-g-C3N4 composite nanoparticles have been synthesized by combining the hydrothermal synthesis and aluminothermic reduction method. The aluminothermic reduction established a shell of amorphous layer contributed by the oxygen vacancy generation, which extended range of sunlight absorption. Meanwhile abundant oxygen vacancies simulate the generation of reactive oxidizing species, resulting in intensive photodegradation ability. The effective degradation process is the result of synergistic interaction among heterojunction, reactive radical species and abundant oxygen vacancies, the degradation efficiency of methylene blue (MB) solution reach to 99.47% within 30 min, which demonstrates the promising prospects of BaTiO3/BaTiO3 − x/g-C3N4 as costing effective, highly stable and efficient photocatalysts.

Photochemical Implications of Changes in the Spectral Properties of Chromophoric Dissolved Organic Matter: A Model Assessment for Surface Waters.

Chromophoric dissolved organic matter (CDOM) is the main sunlight absorber in surface waters and a very important photosensitiser towards the generation of photochemically produced reactive intermediates (PPRIs), which take part in pollutant degradation. The absorption spectrum of CDOM (ACDOM(λ), unitless) can be described by an exponential function that decays with increasing wavelength: ACDOM(λ) = 100 d DOC Ao e-Sλ, where d [m] is water depth, DOC [mgC L-1] is dissolved organic carbon, Ao [L mgC-1 cm-1] is a pre-exponential factor, and S [nm-1] is the spectral slope. Sunlight absorption by CDOM is higher when Ao and DOC are higher and S is lower, and vice versa. By the use of models, here we investigate the impact of changes in CDOM spectral parameters (Ao and S) on the steady-state concentrations of three PPRIs: the hydroxyl radical (•OH), the carbonate radical (CO3•-), and CDOM excited triplet states (3CDOM*). A first finding is that variations in both Ao and S have impacts comparable to DOC variations on the photochemistry of CDOM, when reasonable parameter values are considered. Therefore, natural variability of the spectral parameters or their modifications cannot be neglected. In the natural environment, spectral parameters could, for instance, change because of photobleaching (prolonged exposure of CDOM to sunlight, which decreases Ao and increases S) or of the complex and still poorly predictable effects of climate change. A second finding is that, while the steady-state [3CDOM*] would increase with increasing ACDOM (increasing Ao, decreasing S), the effect of spectral parameters on [•OH] and [CO3•-] depends on the relative roles of CDOM vs. NO3- and NO2- as photochemical •OH sources.

Multistimuli-responsive smart windows based on paraffin-polymer composites

Despite their potential to reduce energy consumption in buildings and increase user's comfort, the general application of smart windows is currently hampered by economic and technological factors. To overcome these limitations, herein we report a new strategy for the fabrication of thermoresponsive smart windows based on polymer films loaded with paraffin nanoparticles. Proper selection of these components allows refractive index matching when the paraffin nanoparticles are in their solid state - i.e., high visible and near-infrared light transparency -, which is lost after melting, thereby resulting in pronounced light scattering - i.e., opacity. As a result, these films show ample modulation of sunlight transmittance upon heating, while additionally exhibiting other advantageous features: facile preparation from low-cost materials; high photostability, flexibility and scalability; and fine tunability of their thermal response. Moreover, by deposition onto transparent electrodes or incorporation of nanostructured photothermal agents, the solar transmittance modulation of our paraffin-polymer composites can also be triggered with low voltages - i.e., to warrant user's control - or sunlight absorption - i.e., to improve self-adaptation to ambient conditions. Actually, films with combined thermal and photothermal activity allow high sunlight transmission in cold weather while efficiently reducing solar heat gain indoors in sunny hot days.

Improvement of mechanical energy using thermal efficiency of hybrid nanofluid on solar aircraft wings: an application of renewable, sustainable energy

ABSTRACT The modern world uses sun-based thermal radiation and nanotechnology to promote new technologies. In addition to solar thermal aircraft, photovoltaic cells, and sun-based hybrid nanofluids, solar energy is the primary source of heat derived from the absorption of sunlight. Researchers are currently investigating the application of nanotechnology to sun-based thermal radiation with the intent of enhancing the efficiency of aircraft flight. This study is focused on the research of heat transport via employing hybrid nanofluid on the interior of solar wings using a parabolic trough solar collector (PTSC) to enrich the investigations of the solar aircraft wing. In addition, the thermodynamics of entropy production for steady tangent hyperbolic fluid is examined for its energy balance and usefulness for significant physical influenced parameters. This study examines the viscoelastic properties of the thermal transfer process of two distinct kinds of nano solid particles, zirconium dioxide and copper (Cu), with non-Newtonian EG (ethylene glycol) as the base fluid. To achieve the model's aims, a novel solution, namely wavelets and the Chebyshev wavelets method (CWM), was employed to solve the velocity, energy equation, and entropy generation. .

Viologens and extended viologen derivatives with mono- and di-hexyl substituents for highly stable all-in-one ECDs and solar cell powered large-area ECDs

Viologen-based electrochromic devices (ECDs) have attracted considerable attention due to their potential applications in smart windows. Herein, two viologen derivatives with N-substituted monohexyl (MHEV) and dihexyl (DHEV), and two extended viologen derivatives with a thiophene unit inserted between the bipyridine moieties and N-substituted monohexyl (m-MHEV) and dihexyl (m-DHEV) were synthesized. All-in-one ECDs were assembled using these materials. m-DHEV and m-MHEV-based ECDs exhibited red and dark orange colors, while DHEV and MHEV-based ECDs exhibited blue and magenta colors. The extended conjugation of the chromophore by the thiophene unit endowed the devices with visible-NIR absorption and excellent cyclic stability. After 10000 cycles, ECDs based on m-DHEV and m-MHEV retained 94.2% and 95.0% of their initial optical contrasts, respectively. A binary chromophore mixture of DHEV and m-DHEV was used to fabricate a uniform large-area ECD (8 cm × 8 cm) with strong sunlight absorption ability. The device maintained high optical contrast (80.2% of initial state) after 2000 cycles. Furthermore, a solar cell powered ECD (8 cm × 8 cm) with negligible loss of optical contrast after 100 cycles of coloring and bleaching under sunlight was developed, demonstrating the application potential of self-powered smart windows using these materials.

Ink‐Stained Chalk: A Low‐Cost 3D Evaporator for Efficient and Stable Solar Desalination

Solar‐driven steam generation is considered one of the most promising techniques to obtain fresh water. Under the same projection area, a 3D evaporator has a larger evaporation area and can get more energy from the environment, resulting into better evaporation performance. 3D evaporators are often hindered by complex and dangerous fabrication processes, special and expensive equipment, and costly raw materials. Herein, a simple method to prepare a low‐cost and highly efficient 3D solar evaporator using chalk and ink that are common in classrooms is proposed. This method does not involve expensive raw materials and any equipment, and the manufacturing process is simple and fast, especially suitable for less developed regions. Thanks to the excellent hydrophilicity of chalk and the strong sunlight absorption of black ink, the ink‐stained chalk (ISC) shows up to 20.49 kg m−2 h−1 of the evaporation rate under one sun illumination. When treating a real seawater sample, ISC prepared from broken or used chalks show highly efficient (8.97–19.91 kg m−2 h−1) and stable (24 h) solar desalination. The ISC presented in this work offers a new avenue to develop 3D solar evaporator for low‐cost and high‐efficient seawater desalination, which is especially attractive for remote and less developed areas.

Vertical graphene on rice-husk-derived SiC/C composite for highly selective photocatalytic CO2 reduction into CO

Coupling graphene-based materials with SiC nanostructures is one of the most feasible strategies to improve the photocatalytic CO2 reduction performance. Here, we synthesized the vertical graphene (VG) sheets on the SiC nanowires achieved from rice husks to form the VG@SiC/C composite, in which the VG sheets possess high surface area, excellent electrical conductivity, and chemical stability, and the SiC nanowires have a suitable bandgap for sunlight absorption. The resulting VG@SiC/C composite provides an enhanced photocatalytic reduction of CO2 to CO and CH4, yielding CO and CH4 evolution yields of 25.5 and 2.3 μmol g−1 h−1, respectively. The achieved CO yield is maximal so far among the SiC-based photocatalysts. The defective VG sheets promote the absorption of sunlight, enhance the CO2 adsorption and activation, increase the separation of photogenerated electron-hole pairs, improve the activity of photocatalyst, and thereby prompt the photocatalytic reduction of CO2 to CO with high yield and selectivity.

Self-lofting of wildfire smoke in the troposphere and stratosphere: simulations and space lidar observations

Abstract. Wildfire smoke is known as a highly absorptive aerosol type in the shortwave wavelength range. The absorption of sunlight by optically thick smoke layers results in heating of the ambient air. This heating is translated into self-lofting of the smoke up to more than 1 km in altitude per day. This study aims for a detailed analysis of tropospheric and stratospheric smoke lofting rates based on simulations and observations. The main goal is to demonstrate that radiative heating of intense smoke plumes is capable of lofting them from the lower and middle free troposphere (injection heights) up to the tropopause without the need of pyrocumulonimbus (pyroCb) convection. The further subsequent ascent within the lower stratosphere (caused by self-lofting) is already well documented in the literature. Simulations of absorbed solar radiation by smoke particles and resulting heating rates, which are then converted into lofting rates, are conducted by using the ECRAD (European Centre for Medium-Range Weather Forecasts Radiation) scheme. As input parameters thermodynamic profiles from CAMS (Copernicus Atmosphere Monitoring Service) reanalysis data, aerosol profiles from ground-based lidar observations, radiosonde potential temperature profiles, CALIOP (Cloud–Aerosol Lidar with Orthogonal Polarization) aerosol measurements, and MODIS (Moderate Resolution Imaging Spectroradiometer) aerosol optical depth retrievals were used. The sensitivity analysis revealed that the lofting rate strongly depends on aerosol optical thickness (AOT), layer depth, layer height, and black carbon (BC) fraction. We also looked at the influence of different meteorological parameters such as cloudiness, relative humidity, and potential temperature gradient. To demonstrate the applicability of our self-lofting model, we compared our simulations with the lofting processes in the stratosphere observed with CALIOP after major pyroCb events (Canadian fires in 2017, Australian fires in 2019–2020). We analyzed long-term CALIOP observations of smoke layers and plumes evolving in the UTLS (upper troposphere and lower stratosphere) height region over Siberia and the adjacent Arctic Ocean during the summer season of 2019. Our results indicate that self-lofting contributed to the vertical transport of smoke. We hypothesize that the formation of a near-tropopause aerosol layer, observed with CALIOP, was the result of self-lofting processes because this is in line with the simulations. Furthermore, Raman-lidar-based aerosol typing (in Leipzig and the High Arctic) clearly indicated the dominance of smoke in the UTLS aerosol layer since August 2019, most probably also the result of smoke self-lofting.

Potential of AMnO3 (A=Ca, Sr, Ba, La) as Active Layer in Inorganic Perovskite Solar Cells.

Inorganic perovskite CaMnO was proposed as a substitution for the TiO anatase in electron transport layers of solar cells containing the hybrid perovskite CH NH PbI based on increased mobility of electrons and better optical matching. Due to a suitable band gap concerning the absorption of sunlight, we investigate the potential of CaMnO and similar manganite perovskites, where Ca is replaced by either Sr, Ba or La, as an absorber layer in inorganic perovskite solar cells. In this study, we have used optical measurements on the synthesized AMnO (A=Ca, Sr, Ba, La) samples to aid density functional theory calculations (DFT) in order to accurately simulate the electronic and optical properties of AMnO compounds and gauge their potential for the role of absorber layer. Both experimental measurements and theoretical calculations show suitable band gap of 1.1-1.5 eV, depending on the compound, and absorption coefficients of the order of cm in the visible part of the spectrum.

Reversed vapor generation with Janus fabric evaporator and comprehensive thermal management for efficient interfacial solar distillation

Interfacial solar steam generation, with high energy efficiency, promotes the solar desalination technology to a new era. However, the problem of low freshwater yield in enclosed distillation system owing to optical loss and insufficient condensation capability remains a challenge. In this work, a reversed interfacial solar distillation system is proposed by combining Janus fabric with comprehensive thermal management to significantly enhance the freshwater yield. Recycled cotton fabric is used to fabricate the low-cost Janus fabric with carbon black@silicone on the top side via a simple and scalable pre-wet coating method. The Janus fabric with high sunlight absorbance (98.0 %) and good sealing properties remarkably guarantees the downward vapor generation to eliminate the optical loss, resulting in the improved freshwater collection of the distiller. Comprehensive thermal management is designed for the distillation system to reduce the heat loss of the evaporator and enhance the condensation effect of the condenser. The optimal Janus fabric-based interfacial solar distiller achieves an outstanding water yield of 1.17 kg m−2h−1 and an efficiency of 78 % under one sun (1 kW m−2) illumination. This work presents a novel design of a high-performance interfacial solar distillation system, offering the potential for large-scale and low-cost industrial production.