Femtosecond pulses used to process perovskites at nanoscale
Scientists have developed a method for the precise, fast and high-quality processing of halide perovskites (CH3NH3PbI3) using ultrafast lasers.
The method promises functional light-emitting materials for solar energy, optical electronics, and metamaterials.
Due to their unique properties, perovskites are up-and-coming materials for solar energy and the development of LEDs and microlasers for photonics. Their major drawback however is their complicated processing requirements. Perovskites easily degrade under the influence of an electron beam, liquids or high temperature, which significantly complicates the manufacturing of functional nanostructures on their surface.
The scientists, from Russian institutes Far Eastern Federal University (FEFU) and ITMO University, together with universities in Germany, Japan, and Australia, have solved this problem using femtosecond laser pulses. In Small, the team describes that with the pulses they are able to process organo-inorganic perovskites and produce high-quality nanostructures with controlled characteristics.
‘Perovskite represents a complex material consisting of organic and inorganic parts. We used ultrashort laser pulses for fast heating and targeted evaporation of the organic part of perovskite,’ said FEFU researcher Alexey Zhizhchenko. ‘Laser intensity was adjusted in such a way to produce melting/evaporation of the organic part leaving the inorganic one unaffected. Such nondestructive processing allowed us to achieve an unprecedented quality of produced perovskite functional structures.’
Using lasers to scribe perovskite films into individual blocks in solar cell production has previously resulted in the outermost sections of the perovskite material losing its functional properties due to temperature degradation. The researchers say their femtosecond laser method can help to solve this problem, enabling the fabrication of high-performance solar cells. In addition, using their method, the visible colour of a perovskite fragment can be changed, enabling the development of solar panels in a variety of colours – which could enable entire buildings to be covered by solar panels without them having to be black.
In addition to solar cells, the new process could also be used to efficiently produce diffraction gratings and microstrip lasers with widths down to 400nm, as well as nanolasers for optical sensors and optical chips. According to the researchers, the simple, fast and cost-effective production of such elements could bring about a new era of computer technology working on the principles of controlled light.
Lastly, through the layer-by-layer thinning of perovskites, the researchers say their technique could be used to design and fabricate more complicated 3D microstructures, for example, micro-scale vortex-emitting lasers, which they say are in high demanded for information multiplexing in next-generation optical communications.