Since 2015, CsPbX3 nanocrystals are experiencing a surge of interest due to the promise of low-cost solar cells, artificial lightning, displays, scintillators, and solution-processed lasers. The new knowledge about CsPbX3 nanocrystals and materials based on them is necessary to choose the most promising applications for investment by governmental organizations and industries. Throughout the project, each of its parts produced results that pushed the current knowledge beyond state of the art, and two examples are highlighted below.
First, the structural analysis of CsPbX3 nanocrystal superlattices by x-ray diffraction revealed that they are exceptionally well-ordered solids. Such an order leads to the peculiar x-ray interference effect, which is very sensitive to the structural parameters of the superlattices and enables their precise structural characterization. These findings led to the development of a general methodology for superlattice characterization by means of x-ray diffraction coupled with an open-source data analysis algorithm. It is anticipated that the discovered approach will become an alternative to resource-intensive synchrothron experiments and make the characterization of similar materials accessible to many researchers in academia and industry.
Second, it was found that directed energy transfer initially plays a minor role in the properties of a single CsPbX3 nanocrystal superlattice. However, a fraction of the nanocrystals coalesces into bigger particles over time inside the superlattice. These bigger particles have smaller bandgaps, which turns on the fast and efficient energy transfer: nearly all of the energy of light absorbed by a superlattice ends up funneling into the large particles. The impact of these findings is two-fold. On the one hand, these results challenge recent reports of collective properties in similar materials by providing an alternative explanation. That contributes to a more accurate understanding of the physics of these materials. On the other hand, the aged superlattices are a new example of an artificial nanomaterial with a built-in directional energy transfer. That finding makes them very attractive for applications in artificial photosynthesis and indicates a future research direction worth of investment and study.
Besides the scientific impact, the project substantially impacted the researcher’s career. The new scientific and soft skills acquired over the course of the project increased technical competence and enhanced the preparation of the researcher for an independent career. The communication and dissemination activities resulted from the project contributed to the strengthening of the researcher’s track record. Overall, the project strengthened the researcher’s motivation and prospects to become an independent leader in the design and photophysics of artificial excitonic materials.
