Researchers Create Light-Emitting Nanoantennas Using Perovskite

A research team from ITMO University has used hybrid perovskites to create light-emitting nanoantennas with enhanced photoluminescence. The nanoantenna and light source are combined in a single nanoparticle. The new nanoantenna can generate, enhance and direct emission wavelengths.

Hybrid perovskites were used because they are known to possess a high refractive index, and they support excitons at room temperature with high binding energies and quantum yield of luminescence.

Nanoantennas obtained by the scientists change their emission wavelength depending on the material composition. Courtesy of E.Y. Tiguntseva, G.P. Zograf et al.

Researchers synthesized perovskite films, then used a pulsed laser ablation technique to transfer material particles from the film surface to another substrate. They observed that the emission of the perovskite nanoparticles could be enhanced if their spectra matched with the Mie-resonant mode. Researchers demonstrated that the enhanced photoluminescence in the nanoantennas was due to the coupling of the nanoantennas’ excitons to dipolar and multipolar Mie resonances.

The team further demonstrated that the halide perovskite nanoantennas could emit light in the range of 530 to 770 nm depending on their composition.

“Perovskites used in our work are semiconductors with luminescence efficiency much higher than that of many other materials. Our study shows that the combination of excitons with Mie resonance in perovskite nanoparticles makes them efficient light sources at room temperature,” said researcher George Zograf.

Researchers said that the radiation spectrum of the nanoparticles could be changed by varying the anions in the material.

“The structure of the material remains the same. We simply use another component in the synthesis of perovskite films. Therefore, it is not necessary to adjust the method each time. It remains the same, yet the emission color of our nanoparticles changes,” said researcher Ekaterina Tiguntseva.

Materials traditionally used in the fabrication of nanostructure-based devices have a limited luminescence efficiency, and typically emit light nondirectionally. The researchers’ technique, based on laser ablation of thin films prepared by wet-chemistry methods, could provide a novel, cost-effective approach for the fabrication of resonant perovskite nanostructures.

The team plans to continue its research on light-emitting perovskite nanoantennas using various components for synthesizing nanoantennas. It is also developing new designs of perovskite nanostructures that could be used to improve ultracompact optical devices.

The research was published in Nano Letters (doi:10.1021/acs.nanolett.7b04727).