Tailored building blocks for tomorrow’s materials The team behind the ERC-backed Heteroplates project are able to precisely control the size and structure of nanocrystals, which can then act as the building blocks of new materials with exciting properties. We spoke to Principal Investigator Professor Yehonadav Bekenstein about the project’s work and its wider implications. Materials today can be built from the bottom up, with researchers able to precisely tune the size and structure of individual parts down to the atomic scale, which opens up new horizons in terms of controlling their electronic structure. The team at Professor Yehonadav Bekenstein’s lab at the Israel Institute of Technology hold deep expertise in growing nanocrystals, which can act as the building blocks of new materials. “We have been very successful in making these nanocrystals and controlling their size, which we have designed to be as similar as possible. As they’re so similar to each other, these nanocrystals stack into very ordered superlattices when they are assembled together,” he outlines. It has been discovered that placing these superlattices sufficiently close to each other leads to a collective emission of light, a phenomenon called superfluorescence; this is a topic of great interest to Professor Bekenstein. “Nanocrystals in the superlattice are able to synchronize and collectively emit pulses of intense light. We can control the wavelength of this collective
emission, it can be either red-shifted or blue-shifted, which allows us to generate ‘quantum light’ from a material that we can tune and control,” he explains. “This light is coherent, which is an important property for quantum applications.” This is also a much easier way of producing quantum light than the more established methods, which typically
Heteroplates project This is one of the topics that Professor Bekenstein is exploring in the ERCbacked Heteroplates project, in which he and his colleagues are working on new ways of developing halide perovskites, a class of semiconductor materials with exciting optoelectronic properties. This work is primarily focused on the caesium-
“Nanocrystals in the superlattice are able to synchronize and collectively emit pulses of intense light. We can control the wavelength of this collective emission, it can be either red-shifted or blue-shifted, which allows us to generate ‘quantum light’ from a material that we can tune and control.” require very low temperatures and extreme conditions. “With our colloidal samples we can now produce quantum light at more relaxed physical conditions, maybe even at room temperature. This method of producing quantum light could be very useful in future applications like quantum communication and computation,” says Professor Bekenstein.
lead bromide (CsPbBr 3) perovskite structure, for quantum light applications, with researchers modifying the overall composition of individual nanocrystals and investigating the wider effects. “We are looking at replacing parts of the bromide the halide - with either chloride or iodides. This allows us to shift the emitted photon wavelength towards either the red or the
Schematics of a superlattice of perovskite nanocrystals emitting green (left) and blue (right) correlated emission superfluorescent light.
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