This type of configuration opens the door to the development of new miniature nanobiosensors and to the design of future systems and networks based on quantum optics. The work of the UPV researchers has been published in the ACS Photonics journal.
The results of the research conducted by the NTC-UPV team combine the benefits of dielectric wireless applications and the benefits of plasmonics. This opens the path to a new generation of ultra-integrated hybrid networks, which is the main contribution of the research.
“We experimentally proved the first wireless dielectric-plasmonic connection thanks to a new type of dielectric nanoantenna that overcomes the limitations of plasmonics, opening the door to new hybrid configurations. The results we have obtained have a direct implication in the design of reconfigurable communication networks inside the chip, in the development of ultra-fast optic devices, and in the practical implementation of ultra-compact biosensors. Thanks to plasmonic structures, this also opens the door to the creation of interfaces with future quantum systems,” says Javier Martí, head of the Nanophotonic Technology Centre of the UPV.
More efficient
Sergio Lechago, researcher at the NTC and co-author of the study, explains that plasmonic devices have enabled the development of important applications in fields such as spectroscopy, near-field and sensing optic microscopy, thanks to their unique capability of manipulating light on a nano level.
Within the communications integrated in the chip, plasmonics enable the development of ultra-compact and affordable devices (modulators, detectors or sources) that can function at very high operation speeds with low energy consumption. “The natural way of interconnecting these devices in the optic chip is by using metallic nanoguides. However, guiding light through these devices leads to very high propagation losses and entails certain restrictions regarding reconfigurability,” explains Carlos García Meca, from the NTC and fellow co-author of the study.
“The use of plasmonic nanoantennas has been proposed to replace and improve the performance of guided metallic interconnections, but these antennas have low directivity and high losses which hinder their use in many practical applications. In this work, we overcame all these limitations by introducing a new dielectric nanoantenna design that acts as an efficient interface for plasmonic systems. This makes it possible to combine the benefits of plasmonics with those of silicon photonics, which can lead to more efficient, fast and reconfigurable chips,” adds García Meca.
This new breakthrough developed in the laboratories of the Centre of Nanophotonic Technology of the UPV could also be applied to fields such as biochemical or agri-food industries, thanks to the role that these hybrid systems can carry out as sensors with multiple purposes, allowing the interaction of light with nanoscopic organic and inorganic structures.
The new method of making mixed halide-perovskites results in solar cells with improved stability and performance. The new method results in better control over perovskite crystallization rates. This means the crystal structure is more ordered, in part due to researchers understanding and taking advantage of the faster crystallization of bromide relative to iodide.
The result is a material with fewer defects and less halide migration and thus less segregation of the bromide and iodide. This in turn means uniform mixing of bromide and iodide across the material, which allows the material to absorb light evenly. The end result is that solar cells made using the new method will perform better under real-world conditions.
Typical halide perovskite solution deposition uses an anti-solvent drip procedure to initiate crystallization of the halide film. The standard anti-solvent method for producing bromide-iodide mixed halide perovskite films often leads to excessive defect formation (e.g., bromide vacancies) owing to the rapid crystallization of bromide vs. iodide-perovskite phases. Simulations show that halide migration is enhanced in the presence of a large population of halide vacancies. This limits the stability of bromide-iodide mixed halide perovskites under light and heat.
In comparison to the anti-solvent approach, the gentler gas-quench method better controls crystallization, first producing a bromide-rich surface layer that then induces top-down columnar growth to form a gradient structure with less bromide in the bulk than in the surface region. The anti-solvent method does not produce such a gradient structure.
In this study, researchers from the National Renewable Energy Laboratory, the University of Toledo, and the University of Colorado Boulder demonstrated that the gas-quench method also produces fewer bromide vacancies and results in materials with a higher quality opto-electronic performance. Solar cells made using the gas-quench method retain desirable light absorption properties and provide enhanced performance in the form of a higher charge carrier mobility, higher open circuit voltage, and enhanced stability.
Scientists make extensive use of X-ray fluorescence to map elements in materials. However, this technique does not have the needed spatial sensitivity unless the probe is finely focused.
Scientists have now found a way to turn X-ray fluorescence into an ultra-high position-sensitive probe to measure tiny internal structures called nanostructures in thin films (Nature Communications, “Reconstruction of Evolving Nanostructures in Ultrathin Films with X-ray Waveguide Fluorescence Holography”). These thin films can be a hundred times finer than a human hair.
