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The ternary zinc nitrides CaZn2N2 and SrZn2N2 are promising materials for solar energy conversion because their direct band gaps are tunable to optimal values, and they contain only earth-abundant ...

The use of nanocrystalline materials in optoelectronic devices has been studied extensively over the last decade. Their size-dependent properties, low cost, low energy solution processing, and the ...

We propose a scheme for ultra-broadband and polarization-insensitive metamaterial perfect absorber (PA) by utilizing a thin metal-insulator-metal (MIM) stack, which is comprised of an array of cross-shaped titanium resonators, a silica dielectric spacer, and an opaque titanium slab. The bandwidth of absorption (A) > 90% is up to 2100 nm, ranging from the visible to near infrared region. At the wavelength range of 400-2500 nm, this metamaterial absorber shows strong absorption of electromagnetic waves. The spectral average absorptivity reaches 93.8% and the maximal absorptivity is up to 99.8%. In addition, the simulations show that the absorption remains high over a broad range of incident angles. Additionally, we have investigated the influences of geometries, structural parameters and material features on the absorption properties. The utilization of titanium rather than the noble metals efficiently lowers the fabrication cost and enhances the thermal stability and biocompatibility, thus paving a way to numerous applications such as solar energy harvesting, imaging, infrared detection and bio-medical techniques.

The solar absorber is a key component in a solar cell as it captures photons and converts them into electron–hole pairs. Its efficiency is driven by the carrier lifetime and the latter is controlled by Shockley–Read–Hall non-radiative processes, which involve defects. Here, we present an ab initio high-throughput screening approach to search for new high-efficiency photovoltaic absorbers taking into account carrier lifetime and recombination through defects. We first show that our methodology can distinguish poor and highly efficient solar absorbers. We then use our approach to identify a handful of defect-tolerant, high carrier lifetime, absorbers among more than 7000 Cu-based known materials. We highlight K3Cu3P2 and Na2CuP as they combine earth-abundance and the potential for high efficiency. Further analysis of our data articulates two challenges in discovering Cu-based solar absorbers: deep anti-site defects lowering the carrier lifetime and low formation-energy copper vacancies leading to metallic behavior. The alkali copper phosphides and pnictides offer unique chemistries that tackle these two issues.

Solar-thermal evaporation is a promising technology for energy-efficient desalination, but salt accumulation on solar absorbers and system longevity are the major challenges that hinder its widespread application. In this study, we present a sustainable Janus wood evaporator that overcomes these challenges and achieves a record-high evaporation efficiencies in hypersaline water, one of the most difficult water sources to treat via desalination. The Janus wood evaporator has asymmetric surface wettability, where the top layer acts as a hydrophobic solar absorber with water blockage and salt resistance, while the bottom hydrophilic wood layer allows for rapid water replenishment and superior thermal insulation. An evaporation efficiency of 82.0% is achieved for 20% NaCl solution under 1 sun, and persistent salt-resistance is observed during a 10-cycle long-term test. To ensure the environmental impact of the Janus wood evaporator, for the first time, a life cycle assessment (LCA) is conducted to compare this Janus wood evaporator with the emerging Janus evaporators, indicating a functional and more sustainable opportunity for off-grid desalination and humanitarian efforts.

A novel technique providing a cost effective sustainable wet chemical etching method of synthesizing black Moly thin films rapidly has been presented. A top- down method for fabricating MoO3 has been investigated to understand the effect of chemical etchant concentration on the structural, morphological and optical properties of the thin films on Mo substrates. The XRD patterns demonstrated the formation of Tugarinovite MoO2 films on Mo substrate after annealing at 500°C in a vacuum. In this work, we developed nanostructured MoO3 on Mo substrate solar absorber, with a high solar absorptance of over 89%. These results suggest that solar absorbers made from refractory metal oxide nanostructures can be used for solar thermal applications.

A conversion of shortwave to longwave radiation heat transfer in building envelope system represents an substantial part in low-energy design campaing. For that reason, an experimental test sample ...

Complex compound semiconductors, such as the emerging solar cell material Cu2ZnSn(S,Se)4 (CZTS), present major experimental challenges in terms of understanding and controlling growth processes and defect formation. This study aims to shed light upon the complicated interplay of the synthesis conditions and CZTS thin film properties. Composition-spread thin films are fabricated in different atmospheric conditions during the annealing step. The span of the single-phase region is identified by a phase analysis combining XRD and Raman mapping. The phase characterisation is strengthened by STEM-EDX analysis. Our results show that the stability of the CZTS phase is strongly affected by the process conditions which is observed as a shift in the secondary phase boundaries and different levels of maximum cation ordering achieved in the different samples. With regard to the photoluminescence intensity, all investigated samples show the same trends: regions with Cu3SnS4 secondary phase show the lowest intensity, while the presence of SnSx secondary phases greatly enhances the photoluminescence intensity. The single-phase region features an overall low photoluminescence intensity without a remarkable composition dependence and we propose the presence of deep defects in absence of secondary phases that limit the radiative recombination. We discuss implications for future efforts in defect engineering toward improving the efficiency of CZTS thin film devices.

In recent years, as a renewable clean energy with many excellent characteristics, solar energy has been widely concerned. In this paper, we propose an ultra-broadband solar absorber based on metal tungsten and semiconductor GaAs structure. A multilayer metal semiconductor composite structure composed of W-Ti-GaAs three-layer films and GaAs gratings is proposed. The finite difference time domain method is used to simulate the performance of the proposed model. High efficiency surface plasmon resonance is excited by adjusting the geometric parameters, and the broadband absorption of up to 2,350 nm in 500–2850 nm is realized. The spectrum of the structure can be changed by adjusting the geometric parameters to meet different needs. The proposed absorber has good oblique incidence characteristics (0–60°) and high short-circuit current characteristics. The geometry of the absorber is clear, easy to manufacture, and has good photoelectric performance. It can realize solar energy collection, light heat conversion, high sensitive sensing and other functions.

A new selective solar absorbers (SSA) optimized to work at 250°C without concentration is presented. The new SSA, based on Cr2O3/Cr multilayers, allows to obtain very high thermal efficiency up to 250°C in evacuated flat solar thermal panels without concentration. Multilayers have been deposited by magnetron sputtering on different copper substrates and characterized by reflectivity measurement as well as calorimetric measurements. Stagnation temperatures close to 400 °C have been obtained with a nominal irradiance of 1000W/m2. These results pave the way to the use of evacuated flat thermal panels for green industrial steam generation.

Solar energy is an inexhaustible clean energy. However, how to improve the absorption efficiency in the visible band is a long-term problem for researchers. Therefore, an electromagnetic wave absorber with an ultra-long absorption spectrum has been widely considered by researchers of optoelectronic materials. A kind of absorbing material based on ZnS material is presented in this paper. Our purpose is for the absorber to achieve a good and wide spectrum of visible light absorption performance. In the wide spectrum band (553.0 THz–793.0 THz) of the absorption spectrum, the average absorption rate of the absorber is above 94%. Using surface plasmon resonance (SPR) and gap surface plasmon mode, the metamaterial absorber was studied in visible light. In particular, the absorber is insensitive to both electric and magnetic absorption. The absorber can operate in complex electromagnetic environments and at high temperatures. This is because the absorber is made of refractory metals. Finally, we discuss and analyze the influence of the parameters regulating the absorber on the absorber absorption efficiency. We have tried to explain why the absorber can produce wideband absorption.

Graphene-based efficient metasurface solar absorber is presented. Graphene monolayer sheet is integrated over silicon dioxide dielectric layer to improve the bandwidth and achieve maximum absorption in the visible region from 430 to 770 THz. Simulation results indicate that the average absorption of our graphene-based metasurface absorber is more than 84% in the visible range. The absorber C-shape metasurface top layer placed above the graphene sheet is made up of tungsten material, and bottom layer made up of tungsten material helps in absorbing incoming electromagnetic light. The resonance frequency can be tuned in a wide frequency range by changing different physical parameters of proposed absorbers design. The absorption efficiency results of the proposed design are also compared with previously published similar absorber design to show the improvement of absorption in the proposed design. The proposed design is useful for designing next-generation graphene-based sensors and photovoltaic devices. Purposed graphene-based metasurface absorber can be used as a basic building block of solar energy-harvesting photovoltaic devices.

The single-element-based selective solar absorber (SSA) is attractive as it does not suffer from mismatched thermal expansion and consequent performance degradation in composite selective solar abs...

Solar-driven interfacial evaporation has received increasing attention due to its energy conversion efficiency being higher than that of conventional photothermal utilization. Although tremendous p...

Aimed at the problem of solar radiation loss from the spacing of ordinary evacuated tube absorber, a solar absorber which combined the external compound parabolic concentrator (CPC) and the all-glass evacuated tube had been developed in this paper. A mathematical model of solar photo-thermal conversion had been created and solved by home-built program, and the experimental setups were carried out for the proposed solar collector system. The photo-thermal performance of the CPC absorber was theoretically and experimentally compared and analyzed with that of the ordinary absorber. The tested and predicted values are in a good agreement and the difference between the two absorbers is also analyzed and performed. Furthermore, the mathematical expressions of optical efficiency versus projected incidence angle for the two absorbers are respectively obtained based on fitting method. It is found that the overall thermal efficiencies in theory and experiment are respectively 68.9% and 66.8% in term of the CPC absorber with an average optical efficiency of 70.5%, and are respectively 54.3% and 53.7% in term of the ordinary absorber with an average optical efficiency of 55.7%. The encouraging research results could provide a fundamental technology reference for the optimization design of performance of solar collector system.

This work investigates the synthesis of a new ternary alloyed metal sulfide semiconductor SnxSb2–yS3 and its application in solar cells. SnxSb2–yS3 nanocrystals were synthesized by incorporating Sn...

Zn3-3xMg3xN2 alloy layers with x ≤ 0.3 can be epitaxially grown at a temperature as low as 140 °C. The bandgap (Eg) of Zn3-3xMg3xN2 widens from 1.2 to 2.5 eV with increasing x. The Eg value of 1.4 eV is obtained at x = 0.18, and the x = 0.18 film has a large absorption coefficient (104–105 cm−1) in the visible region. The Zn3-3xMg3xN2 with Eg = 1.4 eV shows n-type conductivity with a reasonably high electron mobility of 47 cm2 V−1 s−1. Therefore, Zn3-3xMg3xN2 is a candidate for an earth-abundant solar absorber that can be fabricated at low temperatures.

Solar-driven interfacial evaporation, as one of the most effective ways to convert and utilize solar energy, has attracted lot of interest recently. Most of the previous research studies, however, mainly focused on nonpatterned solar absorbers by improving the structural and chemical characteristics of the solar absorbers used in the interfacial evaporation systems. In this work, we investigated the influence of patterned surface on the evaporation performance of solar absorbers. The patterned surfaces studied, which include black patterns and white patterns, were achieved by selectively printing carbon black on the air-laid paper. Such a design leads to the lateral temperature differences between adjacent patterns of the solar absorber under solar illumination. The temperature differences result in the lateral heat and mass transfer between those patterns, which can effectively accelerate solar-driven vapor generation. With similar patterns and same coverage of carbon black, the increase in the circumference of the surface patterns leads to the increase in the evaporation performance. Additionally, we found that the evaporation performance can be optimized through the design of surface patterns, which demonstrates the potential in reducing the usage of the light-absorbing materials in the solar absorber. The findings in this work not only expand the understanding of the interfacial evaporation systems but also offer additional guidelines in designing interfacial evaporation systems.

As photovoltaics have grown to become one of the dominant renewable energy generating technologies, attention has fallen upon thin-film materials as a route to lightweight, flexible and portable solar cells. NaSbS2 has recently been proposed as a non-toxic, earth abundant solar absorber for thin-film cells. In this study, we use a combined theoretical and experimental approach to characterize and assess the electronic and optical properties of NaSbS2 as an emerging solar absorber. Our results, utilising two theoretical efficiency metrics, demonstrate that NaSbS2 may be limited for use in single-junction cells by a forbidden band gap and slow absorption onset. Other features of its electronic structure, however, indicate that the material may still be promising in thermoelectric applications.

In this chapter, we review the basic underlying physics of the spectrally selective coatings (SSCs) utilized for solar thermal absorber applications. The chapter presents an exhaustive review of the oxide systems utilized so far for intrinsic solar absorber coatings in tandem with metal substrates. The criteria for maximizing the performance of SSC, in general, have been discussed with relevant theoretical background, and particular example oxides employed for SSC so far have been reviewed. The effect of nanocrystalline nature and nanosized thickness of the thin films has been discussed exclusively for the first time in the context of oxide SSCs.

As the key approach to enhance the efficient application of solar energy, solar selective absorbers have been extensively investigated in the past years. With great efforts contributed by scientists and engineers all around the world, new materials and excellent structures were achieved in solid progress to stimulate applications in broad fields. In this book, we will present an overview of both theory and experimental methods to fulfill the high-efficiency solar absorber devices. It begins with a historical description of the study and development for the spectrally selective solar absorber materials and structures based on the optical principles and methods in past decades. The optical properties of metals and dielectric materials are addressed to provide the background on how to realize high performance of the solar absorber devices applied in the solar energy field. In the following sections, different types of materials and structures, including the experimental methods, are discussed for practical construction and fabrication of the solar absorber devices, aiming at maximally harvest the solar energy, at the same time to suppress the heat-emission loss effectively. The optical principles and methods used to evaluate the performance of solar absorber devices with broad applications in different physical conditions are presented. The book will be suitable for graduate students in applied physics fields with valuables reference also for the researchers working actively in the solar energy fields.

In this work, for the first time, we studied the temperature-dependent spectral emittance of highly refractory ceramics, e.g. silicon carbide (SiC) and two ultra-high temperature ceramics (tantalum diboride (TaB2), zirconium diboride (ZrB2)) to evaluate their potential for solar tower receivers applications. We measured the spectral normal emittance from 1 µm to 21 µm at temperatures up to 850 °C, in vacuum, by means of a novel experimental setup composed by an electric furnace connected to a FT-IR spectrometer. Comparison with previously published data collected with a different setup was also carried out to validate the results. In addition, the experimental spectral emittance was also compared with the values calculated from hemispherical reflectance at room temperature by means of Kirchhoff’s law. The results show that surface features play a fundamental role in the emittance of investigated ceramics.

Recent technological advances in solar absorber production may have created opportunities for new applications of these materials in buildings. A low-emissivity enhanced polymer-based absorber foil was developed and prototyped to demonstrate feasibility of the concept. This paper describes key development factors leading to a particular composition of the prototype and its testing, specifically spectroscopy measurements (both for shortwave and longwave regions) and environmental impact assessment of its production. It also provides comparison of the tested parameters with commercially available absorbers. The results show that the developed absorber has relatively good thermal emissivity (approx. 0.3), high solar absorption (0.95) and selectivity (3.2), and significantly lower (up to 98%) environmental impacts compared to the commercially available metal-based solar selective absorbers.

This study refers to the optimization of a Selective Solar Absorber to improve the Sun-to-thermal conversion efficiency at mid temperatures in high vacuum flat thermal collectors. Efficiency has been evaluated by using analytical formula and a numerical thermal model. Both results have been experimentally validated using a commercial absorber in a custom experimental set-up. The optimization procedure aimed at obtaining Selective Solar Absorber is presented and discussed in the case of a metal dielectric multilayer based on Cr2O3 and Ti. The importance of adopting a real spectral emissivity curve to estimate high thermal efficiency at high temperatures in selective solar absorber is outlined. Optimized absorber multilayers can be 8% more efficient than the commercial alternative at 250 °C operating temperatures and up to 27% more efficient at 300 °C. Once the multilayer has been optimized the choice of a very low emissivity substrate such as copper allows to further improve efficiency and to reach stagnation temperature higher than 400 °C without Sun concentration.

Multilayer optical film plays a significant role in broad fields of optical application. Due to the nonlinear relationship between the dispersion characteristics of optical materials and the actual performance parameters of optical thin films, it is challenging to optimize optical thin film structure with the traditional models. In this paper, we present an implementation of Deep Q-learning, which suited for the most part for optical thin film. As a set of concrete demonstrations, we optimize solar absorber. The optimal program could optimal this solar absorber in 500 epoch (about 200 steps per-epoch) without any human intervention. Search results perform better than researchers’ manual searches.

We demonstrated the broadband and near-perfect solar absorption of carbon nanotube (CNT) based black coating prepared by low-cost wet-deposition method on reflective metal surface for mid-temperature non-evacuated Concentrated Solar Power (CSP) application. The controlled density of CNTs in the ceramic matrix exhibits absorptance of 0.985 in the entire solar spectrum and emittance of 0.90 in IR region. The coating exhibits durable superhydrophilic property with 0° contact angle after plasma treatment without affecting the solar absorptance and excellent coating adhesion measured at 85-95% of the area. The efficiency of the coating was evaluated by analytical models and it reveals that the CNT-based coating shows higher efficiency at low temperature and at high concentration ratio than that of selective coatings.

The innovative ultra-high vacuum technology applied to solar thermal flat panels, allows to reach high operating temperatures (up to 200 °C) without concentration, cutting out both convective and conductive thermal losses of the internal gas. The system losses are mainly due to the radiative energy emitted by the absorber. In this paper, a power balance equation has been used to perform the best fit of the data recorded with the absorber first exposed to the Sun illumination (up to the stagnation temperature, typically above 300 °C) and then cooled down by using an opaque shield. In particular, the fitting procedure is useful to evaluate the spectrally averaged absorptivity and the temperature dependent spectrally averaged emissivity of the absorber in a realistic operating condition.

This study investigates the influence of Ni–Al coating thickness on the spectral selectivity and thermal performance of a parabolic trough collector (PTC). Three thicknesses of Ni–Al coating for use as solar absorber material were successfully prepared on the outer surface of a stainless steel 316L (SS) tube by flame spray. The phase, morphology, and reflectance (R) of the Ni–Al coatings were characterized using several techniques. The PTC and solar receiver tube were specially designed and constructed for observing the collector thermal performance by following ASHRAE 93-1986. Looking at the results, the actual average thicknesses of the three Ni–Al coatings turn out to be 195, 215, and 299 μm. The morphology and chemical composition of all three thicknesses are similar. The chemical composition in the cross-sectional view exhibits non-uniform distribution. The three thicknesses of the coating are composed of NiO and Al2O3 phases, which also corresponded to the results of SEM–EDX mapping. The differences in a solar absorptance (α) of the three thicknesses of Ni–Al coating are not statistically significant, with an average α value of 0.74–0.75. However, there are differences in thermal efficiency of the PTC depending on the thickness of the Ni–Al coating. Of the three samples, the thickest one (299 µm) demonstrates the highest ability to convert solar radiation into thermal energy.

Wavelength-selective nanoantenna emitters have attracted considerable attention due to their widespread applications ranging from thermal radiation management to thermophotovoltaics. In this paper, we design a wavelength-selective nanoantenna emitter based on the excitation of gap-surface plasmon modes using a metal–insulator–metal configuration (silicon dioxide (SiO2) sandwiched between silver (Ag) layers) for satisfying multiple infrared applications. The proposed design, which is called design I, realizes triple narrowband perfect absorptions at the resonance wavelengths of 1524nm,2279nm, and 6000nm, which perfectly match the atmospheric absorption bands while maintaining relatively low emissivity in the atmospheric transparency windows of 3-5 µm and 8-12 µm. Later, the functionality of design I is extended, which is called design II, to include a broadband absorption at the near-infrared region to minimize the solar irradiation reflection from the nanoantenna emitter. Finally, single- and three-layer graphene are introduced to provide a real-time tuning of the infrared signature of the proposed nanoantenna emitter (design II). It is also demonstrated that the three-layer graphene structure can suppress an undesired absorption resonance wavelength related to the intrinsic vibrational modes (optical phonons) of the SiO2 layer by 53.19% compared to 25.53% for the single-layer one. The spectral analysis of design I is validated using both analytical and numerical approaches where the numerical simulation domain is extended for the analysis of design II. The thermal characteristic analyses of design I and design II (without/with graphene layers) reveal that infrared signatures of the blackbody radiation are significantly reduced for the whole wavelength spectrum at least by 96% and 91% within a wide temperature ranging from room temperature to 500K, respectively.

Herein, both from the experimental and theoretical point of view, the optical absorption properties of a subphthalocyanine (SubPc), an organic macrocycle commonly used as a sunlight harvester, coupled to metallic optical cavities are analyzed. How different electronic transitions characteristic of this compound and specifically those that give rise to excitonic (Q band) and charge transfer (CT band) transitions couple to optical cavity modes is investigated. It is observed that whereas the CT band couples weakly to the cavity, the Q band transitions show evidence of hybridization with the photon eigenstates of the resonator, a distinctive trait of the strong coupling regime. As a result of the different coupling regimes of the two electronic transitions, very different spectral and directional light-harvesting features are observed, which for the weakly coupled CT transitions are mainly determined by the highly dispersive cavity modes and for the strongly coupled Q band by the less angle-dependent exciton-polariton bands. Modeling also allows discriminating parasitic from productive absorption in each case, enabling the estimation of the expected losses in a solar cell acting as an optical resonator.

Tantalum carbide, as a Ultra-High Temperature Ceramic, is known to be characterized by intrinsic spectral selectivity, which makes it attractive for novel high-temperature thermal solar absorbers. However, a weakness point of TaC is the solar absorbance, which, in absence of any treatment, is usually lower than that of other materials currently under development for solar absorber applications. In the present work we have investigated the effect of surface texturing by femtosecond laser machining on this superhard material. Laser-induced microstructural and optical property changes have been characterized in two samples with different starting roughness and for four laser treatments each, as a function of the accumulated laser fluence. As the interaction with the laser beam takes place and gets stronger, both surface and chemical composition changes appear. Optical properties are heavily affected: solar absorbance considerably increases, at a slight expense of spectral selectivity.

In this study, a simple and novel oxide-nanoparticles-based process was applied to prepare Cu2FeSnS4 (CITS) thin films. Firstly, the low cost and naturally abundant oxides (e.g. CuO, Fe2O3 and SnO2) were coated on the glass substrate. Secondly, CITS thin films were grown through the sulfurization of oxides precursors in a low toxic sulfur atmosphere. To investigate the phase transformation during sulfurization, the different annealing temperatures were used. It was found that the intermediate phase Cu3SnS4 and Cu2Sn3S7 existed during the CITS growth. Finally, the phase-pure CITS films with large grains were obtained when the sulfurization temperature increased to 580 °C. Furthermore, an obvious photoelectric response of CITS thin film is displayed, which suggests its potential application as one kind of low cost solar absorber materials.

The field of photovoltaics is undergoing a surge of interest following the recent discovery of the lead hybrid perovskites as a remarkably efficient class of solar absorber. Of these, methylammonium lead iodide (MAPI) has garnered significant attention due to its record breaking efficiencies, however, there are growing concerns surrounding its long-term stability. Many of the excellent properties seen in hybrid perovskites are thought to derive from the 6s2 electronic configuration of lead, a configuration seen in a range of post-transition metal compounds. In this review we look beyond MAPI to other ns2 solar absorbers, with the aim of identifying those materials likely to achieve high efficiencies. The ideal properties essential to produce highly efficient solar cells are discussed and used as a framework to assess the broad range of compounds this field encompasses. Bringing together the lessons learned from this wide-ranging collection of materials will be essential as attention turns toward producing the next generation of solar absorbers.

Tarkista embargo! /MSo To meet the need to the “customized eco-friendly” design of flexible solar materials in vivid colors, here, the solar kitchen foils are devised which are selective, omnidirectional, and colored. The experimental and simulation results enable drawing the roadmap of the fabrication of glowing, colored flat foils for diverse energy, packaging, and decoration purposes. A new gold-free golden foil, i.e., mimicking gold optically and visually, is designed as a prototype for the sustainable fabrication of advanced colored foils with glowing colors, e.g., golden with no need to neither hazardous anodization nor dying processes. The solar foil performs based on the newly developed concept of the polarizonic interference allowing production of omnidirectional structural colors by a disordered plasmonic nanocomposite. As the specific highlight, selective reflective coloration by plasmonic dipoles in a hybrid dielectric host, i.e., the building block of ultrathin solar absorbers with tailored, vivid colors, on an aluminum foil is demonstrated. In terms of the production technique, the applied sputtering technique is simple, versatile, cost-effective, and compatible with the industrial packaging, decoration, and solar absorber manufacturing processes. Thus, it holds great promise for creation of advanced, flexible, colored solar absorbers in a simple, scalable, and sustainable fashion.

Here we present a robust molecular precursor-based approach to synthesize high-quality thin films of silver bismuth sulfide (AgBiS2). Pure-phase cubic AgBiS2 thin films are prepared, which are smoo...

Since solar energy is the ultimate energy resource and a significant amount of global energy utilization goes through heat, there have been persistent efforts for centuries to develop devices and systems for solar–thermal conversion. Most recently, interfacial solar vapor generation, as an emerging concept of solar–thermal conversion, has gained significant attention for its great potentials in various fields such as desalination, sterilization, catalysis, etc. With the advances of rationally designed materials and structures and photon and thermal management at the nanoscale, interfacial solar vapor generation has demonstrated both thermodynamic and kinetical advantages over conventional strategies. In this review, we aim to illustrate the definition, mechanism and figures of merit of interfacial solar vapor generation, and to summarize the development progress of relevant materials and applications, as well as to provide a prospective view of the future.

CSP (Concentrated Solar Power) plants technologies use the concentration of solar energy on a receiver to produce heat and then electricity by a thermodynamical process. A solar absorber material is used to convert the energy carried by light into heat. This type of material works at high temperatures (up to 1000 °C) under a highly concentrated solar flux (up to x1000 or more). Optical properties determine the performance of absorbers and it is thus necessary to measure their spectral absorptance and emittance. Solar absorptance is directly linked to the capacity of the absorber material to convert the solar flux into heat. Emittance drives the radiative thermal losses for the heated absorber and depends on the absorber temperature. The characterization of a material in operational conditions at high temperatures requires advanced apparatuses, and different measurement methods exist for the characterization of these two quantities of relevance regarding an absorber. A Round Robin Test (RRT) was conducted with the objective of comparing different new optical apparatuses and methods for measuring the emittance or luminance of various solar absorbers in air. Measurements were carried out directly at temperatures up to 560 °C while heating the samples, and also indirectly by hemispherical reflectance measurements at room temperature. In this paper, the Round Robin Test procedure to compare apparatuses is described, as well as the corresponding reflectance and emittance results on four types of materials. In addition, a discussion of some factors of influence over high temperature measurements in air and of the observed discrepancies among results from the evaluators is presented. The reliability of reflectance/emittance measurements is also demonstrated and statistics of deviations from the mean value are analysed. These allow us to infer information about measurement reproducibility. The reflectance spectra of all samples after high temperature measurements in air (up to 500 °C) do not show any significant changes.

Despite its high solar absorbance and surface coating abilities, pristine graphene as a semimetal is not promising for photovoltaic applications. In this study, we predict that Glycine (Gly), an amino acid, which is normally bound to pristine graphene by a weak van der Waals attraction, can form an organic coating durable to ambient condition when adsorbed on vacancy patterned graphene surface. Moreover, adsorbed Gly coating induces metal-insulator transition and concomitantly increases the solar absorbance of pristine graphene more than three times. This way, graphene attain critical functionalities to be used in solar energy and photovoltaic applications.Despite its high solar absorbance and surface coating abilities, pristine graphene as a semimetal is not promising for photovoltaic applications. In this study, we predict that Glycine (Gly), an amino acid, which is normally bound to pristine graphene by a weak van der Waals attraction, can form an organic coating durable to ambient condition when adsorbed on vacancy patterned graphene surface. Moreover, adsorbed Gly coating induces metal-insulator transition and concomitantly increases the solar absorbance of pristine graphene more than three times. This way, graphene attain critical functionalities to be used in solar energy and photovoltaic applications.

A novel broadband solar absorber is numerically studied based on the commercial digital versatile disc (DVD). Refractory titanium (Ti) material is artificially coated onto the surface of the DVD, which then forms the plasmonic resonant metasurface. Spectral average absorption reaches 91.3% in the whole visible and near-infrared range (0.38–1.50 μm). The total solar absorption in these energy regions is also up to 92.1%. Moreover, the high spectral absorption is insensitive to the incident angle. Interestingly, the absorption is observed to be with high tolerance for the polarized light even if the grating structure is used in the platform. These features suggest that the broadband solar absorption can be maintained well under complex electromagnetic surroundings. Otherwise, the absorbed energy is mainly confined at the proximity surface area of the Ti cavity, which suggests the strong plasmonic near-field localization and paves the feasible way to carry out the local heating operation for thermal antibacterial/antivirus applications.

Earth-abundant and nontoxic absorber materials have been extensively studied for thin-film solar cells. One of the most viable candidate materials for solar absorber applications is Cu2SnS3 (CTS). The feasibility of producing fully dense CTS materials by combining mechanical alloying (MA) and spark plasma sintering (SPS) is reported for the first time. X-ray diffraction analysis revealed the formation of the CTS compound, with a monoclinic structure, after 2 h of MA. SPS consolidation of the CTS powder particles was performed at 600 °C yielding high densification without much sulfur loss or oxidation. Optical band gaps ranging from 1.34 eV to 1.11 eV were estimated with diffuse reflectance measurements. The approach used constitutes a simple and economic alternative to conventional sintering techniques already used to prepare thin-films from nanopowders and, in the near future, it is believed that SPS will be able to produce dense absorber layers of CTS for thin-film solar cells.