Phys.org April 19, 2024 The light-induced ultrafast switching between molecular isomers norbornadiene and quadricyclane can reversibly store and release a substantial amount of chemical energy. Prior work observed signatures of ultrafast molecular dynamics in both isomers upon ultraviolet excitation but could not follow the electronic relaxation all the way back to the ground state experimentally. An international team of researchers (USA – Kansas State University, University of Nebraska–Lincoln, SLAC National Accelerator Laboratory, Brown University, UK, Germany, Italy, Sweden, Australia) identified two competing pathways by which electronically excited quadricyclane molecules relaxed to the electronic ground state. The fast pathway (<100 femtoseconds) was […]
Category Archives: Solar energy
Physicists develop new solar cell design for better efficiency
Phys.org February 20, 2024 Photovoltaics offers a large potential for the supply of clean and renewable energy. Silicon solar cells used for this purpose have efficiency limits. One reason for this is that some of the energy from short-wave radiation is not converted into electricity, but into unwanted heat. Through computer simulation researchers in Germany showed that to increase the efficiency, the silicon solar cell could be provided with an organic layer, for example made from the semiconductor tetracene. Short-wave light is absorbed in this layer and converted into high-energy excitons. These excitons decay in the tetracene into two low-energy […]
Copper-doped tungstic acid nanocrystals transform infrared light conversion
Nanowerk September 13, 2023 The technology to utilize the full spectrum of solar radiation is still in its infancy as conventional methods constrain their all-solar response. Researchers in Japan have proposed using – submerged photosynthesis of crystallites (SPsC). They showed that strategic doping with copper and oxygen vacancies can induce opto-critical phases from the non-stoichiometric tungstic acids. These opto-critical phases enabled a dynamic equilibrium shift in lattice defect stabilization, facilitating an unprecedented whole solar wavelength response. The response manifested photo-assisted water evaporation, and photo-electrochemical characteristics. According to the researchers their strategy of harnessing all-solar energy, the one-pot SPsC strategy, may […]
Team develops strategy to regulate light absorption behaviors of titanium oxo clusters
Phys.org January 23, 2023 Researchers in China constructed two heterometallic clusters to improve the solar absorption and performance of titanium oxo clusters. Their studies indicated that these structures exhibited enhanced visible-light absorption and significantly reduced optical band gaps which could be mainly attributed to the introduction of electron-rich molybdenum (Mo) pairs as heterometals. They found that the electron-rich Mo–Mo pairs could be introduced to titanium oxo clusters to enhance visible-light absorption. They attributed the reduction in the band gaps to the introduction of electron-rich Mo-Mo pairs as heterometals. They also found that the bands shift effectively toward the visible-light region. […]
Self-repairing healing solar cells recovering in the dark of the night
Nanowerk January 4, 2023 Perovskite solar cells degrade when exposed to sunlight, which results in decreasing performance over time. An international team of researchers (Sweden, Israel) demonstrated that metal halide perovskite solar cells, which degrade in sunlight, can rebuild their efficiency at night, when it’s dark. They exposed single crystals of lead-based metal halide perovskites to powerful lasers, which made them lose their ability to glow. However, they found that the material regained its photoluminescence following some recuperation time in darkness. They observed this in a solar cell’s thin, multicrystalline layer and the other one in single crystals. It is […]
Paper-thin solar cell can turn any surface into a power source (w/video)
Nanowerk December 10, 2022 To date, demonstrations of ultra-thin photovoltaics have been limited to small-scale devices, often prepared on glass carrier substrates with only a few layers solution-processed. Researchers at MIT have demonstrated large-area, ultra-thin organic photovoltaic (PV) modules produced with scalable solution-based printing processes for all layers. They were transferred onto lightweight and high-strength composite fabrics, resulting in durable fabric-PV systems ∼50 microns thin, weighing under 1 gram over the module are, and having a specific power of 370 W kg−1. Integration of the ultra-thin modules onto composite fabrics lends mechanical resilience to allow the fabric-PV systems to maintain […]
Glass-like shells of diatoms help turn light into energy in dim conditions
Nanowerk November 22, 2022 Using a toolkit consisting of numerical models and four microscopy techniques, researchers in Canada evaluated the optical response of frustules belonging to the species Nitzschia filiformis. Localized regions of the frustule exhibited functionalities including diffraction, lensing, waveguiding, circulation, filtering, resonances, and dispersion control. They showed that these functionalities are complementary to each other in contributing to the solar energy harvesting mechanisms of capture, redistribution, and retention. In this context, frustule performance was enhanced by perturbations to its sub-wavelength structure. According to the researchers their finding provides quantitative support to the hypothesis that the frustule enhances photosynthesis […]
Nanoparticles increase light scattering, boost solar cell performance
Phys.org August 3, 2022 An international team of researchers (USA – Pennsylvania State University, Australia, Italy) has demonstrated that adding any nanomaterial to solar material boosts its efficiency because of the enhanced light scattering as confirmed by theoretical calculations. Adding the nanoparticles boosted the efficiency of perovskite solar cells by 1% in the study. Redistribution of the optical field and consequently a homogenization of the optical field can lead to a reduced photocarrier loss and provide a noticeable photocurrent enhancement (ca. 7%), which explains the general photocurrent improvement in solar cells with nanomaterials…read more. TECHNICAL ARTICLE
Optimizing silicon structure to reduce reflection
Nanowerk April 14, 2022 Researchers in China examined changes in the porous structure of silicon to make it less reflective and thus a better material for solar absorbing technology. Currently, the reflectivity of porous silicon prepared using electrochemical methods is around 5 to 10 per cent, with the lowest reflectivity being 4.7 per cent for light in the wavelength range of 300 to 1000 nanometres. They calculated and compared the surface reflectivity of porous silicon structures with different pore sizes. They discovered that the porous silicon structure when prepared under the optimal corrosion parameters can achieve an average reflectivity as […]
Wide-visible-light-responsive photocatalyst boosts solar water splitting
Phys.org January 31, 2022 Bismuth vanadate (BiVO4) has been widely investigated as a photocatalyst or photoanode for solar water splitting, but its activity is hindered by inefficient cocatalysts and limited understanding of the underlying mechanism. An international team of researchers (China, Japan) demonstrated significantly enhanced water oxidation on the particulate BiVO4 photocatalyst via in situ facet-selective photodeposition of dual-cocatalysts that exist separately as metallic Ir nanoparticles and nanocomposite of FeOOH and CoOOH (denoted as FeCoOx), as revealed by advanced techniques. The mechanism of water oxidation promoted by the dual-cocatalysts is experimentally and theoretically unraveled, and mainly ascribed to the synergistic […]