The Power of Nanospectroscopy
Most spectroscopic techniques do not offer high spatial resolution and the observed volume is quite large. In the field of nanocrystals this implies that measured signals always stem from a large ensemble of nanocrystals. In many cases, however, these nanocrystals differ from each other. These variations affect both the morphology as well as the resulting optical properties of the nanocrystals. Consequently, distinct features are hidden under an inhomogeneously broadened signal in the optical spectra.
Single nanocrystals at low temperatures
Our technique allows us to measure the photoluminescence dynamics of single nanocrystals. Furthermore, a cryostat enables data acquisition at temperatures ranging from room temperature down to 5K. By cooling the nanocrystals, the photoluminescence linewidth can be further decreased and temperature effects can be studied.
Halide perovskite nanocrystals are the material we are currently mainly focusing on. We apply single nanocrystal spectroscopy to variously shaped nanocrystals, such as nanocubes or nanoplatelets. These measurements lead to fundamental insights into the material, deepening our understanding of this exciting material class. This kowledge is then used to enhance and tailor the nanocrystal properties and optimize or develop new synthetic routes.
Our research begins with the synthesis of the materials, which requires expertise in chemistry and material science. The spectroscopic measurements and other characterization techniques and their interpretation demand knowledge of semiconductor physics and optics. Lastly, experience in device fabrication is needed to implement and test the performance of the nanocrystals in applications like LEDs or solar cells. To effectively engage in all of these research areas, scientists with different backgrounds have to come together; leading to a diversified and fascinating environment.