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•A highly efficient photo-thermal membrane was fabricated with 3D light-trapping structure.•The membrane has broad spectrum and wide range of absorption angles of light.•The membrane ...has excellent photothermal conversion capacity, efficient solar desalination performance and salt resistance.•The membrane is scale production, low-cost, and recyclable.
Solar-driven interfacial water evaporation has been recognized as one of the promising methods to solve the problem of fresh water shortage. However, due to the dependence of the incident angle of light, the light absorption performance of materials in practical applications is limited. Herein, a three-dimensional (3D) light-trapping structure was constructed by zinc oxide nanowires within carbon-based nanofiber membrane using electrospinning technology, hydrothermal growth and magnetron sputtering techniques for multi-angle wide-spectrum light absorption. It has excellent average absorption (>90 %) performance in a wide range of angles (0°- 80°), and a rapid photo-thermal conversion capacity (70℃ after 30 s solar illumination), which are higher than that in previous literature. The average absorption of light from 200 to 2500 nm can reach 95 %. Under 1 sun irradiation (1 kW m-2), the solar evaporation rate can reach 1.73 kg m-2h-1, and the evaporation efficiency can reach 94 %. The multi-angle wide-spectrum light-absorption of the membrane might provide a promising strategy for collecting water in other practical applications.
To reduce the receiver's energy loss at high temperatures for the next-generation concentrating solar power plant, a novel multi-scale receiver is proposed by combing fin-like structures in the ...macroscale and light-trapping coatings in the nanoscale. The fin-like structure can reabsorb the reflected solar energy while the light-trapping nanostructured coating can increase solar absorption and reduce infrared emissivity. A multi-scale numerical model is developed to evaluate the receiver's optical and thermal performance. It is found that the multi-scale solar receiver can achieve a receiver efficiency of 0.904 at the solar time of 12:00 on spring equinox. However, it is also found that the maximum film temperature of the leading-edge tube will exceed 800 °C, which may decompose the current nitrate salt. To solve this problem, a white coating is used for leading-edge tubes to reduce the temperature by decreasing the maximum heat flux. The results show that this method can effectively regulate the overheating of the leading-edge tube. The maximum film temperature was successfully reduced to less than 800 °C at nearly no expenses of the absorbed solar energy. The study provides a new sight to achieve a receiver efficiency of more than 0.9 for the next generation concentrating solar power plants.
Membrane separation technology with superwetting surfaces is ideal for treating water pollution. However, the fouling problem of membranes limits their practical application in this field. Membranes ...with self-cleaning property during the separation are the key to solve this problem. In this study, inspired by the light-trapping effect of the moth-eye, a kind of composite membrane with efficient self-cleaning by photocatalytic degradation was proposed. The composite membrane is based on polyvinyl alcohol cross-linked tannic acid (PVA-TA) and its photocatalytic function is achieved by doping magnetic titanium dioxide nanoparticles (MTiO2) as well as MXene. Meanwhile, its surface was constructed by magnetically controlled self-assembly method using MTiO2 to mimic the moth-eye structure. The composite membrane has superhydrophilic/underwater superoleophobic, excellent oil-water separation efficiency (99.85%) and long service life (64 cycles). In addition, due to the light-trapping effect of the bionic moth-eye structure and the redox reaction at the interface of MTiO2-MXene composites under sunlight irradiation, the membrane can achieve efficient and convenient photocatalytic degradation self-cleaning by sunlight irradiation. This study will provide new insights into the self-cleaning method of oil-water separation materials.
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•Construction of high light absorption efficiency surface by magnetron self-assembly method inspired by the light-trapping effect of moth-eye structure.•Redox reaction occur at the interface of MTiO2 and MXene composite under sunlight irradiation.•The composite membrane shows excellent oil-water separation performance and long service life.•The composite membrane has excellent sunlight-catalyzed degradation self-cleaning property.
Two-dimensional (2D) semiconductors provide a unique opportunity for optoelectronics due to their layered atomic structure and electronic and optical properties. To date, a majority of the ...application-oriented research in this field has been focused on field-effect electronics as well as photodetectors and light emitting diodes. Here we present a perspective on the use of 2D semiconductors for photovoltaic applications. We discuss photonic device designs that enable light trapping in nanometer-thickness absorber layers, and we also outline schemes for efficient carrier transport and collection. We further provide theoretical estimates of efficiency indicating that 2D semiconductors can indeed be competitive with and complementary to conventional photovoltaics, based on favorable energy bandgap, absorption, external radiative efficiency, along with recent experimental demonstrations. Photonic and electronic design of 2D semiconductor photovoltaics represents a new direction for realizing ultrathin, efficient solar cells with applications ranging from conventional power generation to portable and ultralight solar power.
Thin, flexible, and efficient silicon solar cells would revolutionize the photovoltaic market and open up new opportunities for PV integration. However, as an indirect semiconductor, silicon exhibits ...weak absorption for infrared photons and the efficient absorption of the full above bandgap solar spectrum requires careful photon management. This review paper provides an overview on the fundamental physics of light trapping and explains known theoretical limits. Technologies that have been developed to improve light trapping will be discussed, and limitations will be addressed.
Thin, flexible, and efficient silicon solar cells would revolutionize the photovoltaic market and open up new opportunities for PV integration. However, as an indirect semiconductor, silicon exhibits weak absorption for infrared photons and the efficient absorption of the full above bandgap solar spectrum requires careful photon management. This review paper provides an overview on the fundamental physics of light trapping and explains known theoretical limits.
We fabricate a novel light trapping induced wrinkled nanocone SERS substrate on flexible and transparent PET film for highly sensitive TNT detection based on Meisenheimer complex.
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•We ...report a novel light trapping induced wrinkled nanocone SERS substrate on flexible and transparent PET film.•Highly sensitive TNT detection employed the electromagnetic coupling effect based on Meisenheimer complex.•This flexible substrate can be widely used to detect analytes on irregular or rough surface of the suspicious items.
We reported an ultrasensitive TNT detection method via a novel light trapping induced wrinkled nanocone flexible SERS substrate, which was fabricated by colloidal lithography and oxygen plasma etching on transparent PET film. Especially, a set of nanowrinkles with 50−60 nm was found on the sidewall of nanocone after etching. By coating 30 nm gold film, this flexible SERS substrate provided uniform hot spots, which demonstrated high reproducibility and sensitivity. 4-ATP molecules based Meisenheimer complex, which is a well-known charge-transfer interaction between electron-poor TNT and electron-rich amino group, was taken to detect ultra-low concentration of TNT explosive. The Raman signal of TNT was significantly enhanced by charge-transfer, light trapping effect and coupled electromagnetic field. The detection sensitivity of TNT molecules was as low as 10−13mol/L, and show a good linear response in the range from 10−8 to 10−13mol/L. Consequently, by brushing this flexible SERS substrate onto a cloth bag, trace amount of TNT residues with concentration as low as 10-10mol/L can be easily analyzed. It is believed that the proposed highly sensitive and uniform flexible substrate provides a significant solution for trace analysis of TNT residue in criminal forensic, military and security check.
Porous silicon structures are effective in trapping light due to the abundance of pores on their surface, finding widespread use in optical applications like photoelectric conversion, photon ...collection, and detection. We have successfully created micro-porous silicon with exceptionally high antireflection performance through electrochemical etching using different concentrations of silver catalysts. Results show that this germanium coated porous silicon structure has a smaller range of pore sizes, leading to a reduced reflectivity of 2.6 % under light radiation with wavelengths. To understand the antireflective mechanism further, we explored the surface reflectivity of porous silicon structures by coating the germanium metal on the porous structure. Importantly, germanium coated porous silicon structures with high surface quality and well-preserved pore integrity are identified as beneficial for achieving lower reflectivity in the incident light wavelength range of 300–1200 nm. These findings are significant for the design of porous silicon antireflective materials.
Antimony sulfide (Sb2S3) as a wide‐bandgap, nontoxic, and stable photovoltaic material reveals great potential for the uppermost cells in Si‐based tandem cell stacks. Sb2S3 solar cells with a ...compatible process, acceptable cost, and high efficiency therefore become the mandatory prerequisites to match silicon bottom cells. The performance of vacuum processed Sb2S3 device is pinned by bulk and interfacial recombination. Herein, a thermally treated TiO2 buffer layer induces quasiepitaxial growth of vertical orientation Sb2S3 absorber overcoming interface defects and absorber transport loss. Such novel growth could pronouncedly improve the open‐circuit voltage (Voc) due to the superior interface quality and intraribbon transport. The epitaxial rough Sb2S3 surface shows a texturized‐like morphology. It is optimized by tuning the grain sizes to form strong light trapping effect, which further enhances the short‐circuit current density (Jsc) with a 16% improvement. The final optimal device with high stability obtains a power conversion efficiency of 5.4%, which is the best efficiency for full‐inorganic Sb2S3 solar cells. The present developed quasiepitaxy strategy supports a superior interface, vertical orientation, and surface light trapping effect, which provides a new perspective for efficient noncubic material thin film solar cells.
A facile and efficient strategy is developed to achieve quasiepitaxy growth of hk1 oriented Sb2S3 films by controlling the exposure facet and oxygen vacancy of the TiO2 film. Owing to the superior interface, vertical orientation, and light trapping effect, the epitaxial Sb2S3 solar cell obtains an efficiency of 5.4%, which is the best efficiency for full‐inorganic planar Sb2S3 solar cells.
•A comparative evaluation of various wet texturing methods is reported.•The new recipe with KOH and additives shows high performance of light trapping.•KOH-based surface texturing is more suitable ...for mass production and high efficiency of c-Si solar cells.
Texturing the surface of crystalline silicon wafers is a very important step in the production of high-efficiency solar cells. Alkaline texturing creates pyramids on the silicon surface, lowering surface reflectivity and improving light trapping in solar cells. This article provides a comparative evaluation of various wet texturing methods using alkaline solutions with or without additives commonly known as surfactants. One method uses sodium hydroxide (NaOH) and isopropyl alcohol (IPA) to create a surface with a height of about 4.5 μm by texturing for about 30 min, while the other method uses potassium hydroxide (KOH) and other additions known as additives. Texturing was performed using chemicals for only 15 min to create a surface shape with a height of approximately 3.5 μm. Additionally, the two solutions showed reflectance of 8.01 % or 12.1 % in 400–1100 nm, respectively. Both processes used alkaline etching at 80 °C for saw damage removal (SDR) before texturing. These processes have also been investigated in terms of removing potential organic contaminants from surfaces. Characterization techniques used throughout the investigation included optical microscopy, surface reflectance measurements, scanning electron microscopy (SEM), and electron dispersive spectroscopy (EDS). The purpose of this study is to confirm through experiments which texturing techniques are more suitable for mass production and to develop time- and cost-effective texturing techniques for industrial production of high-throughput, high-efficiency solar cells.
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