Researchers at Ludwig Maximilian Univ. of Munich, Germany (LMU) have succeeded in synthesizing perovskite nanocrystals in the form of ultrathin nanoplatelets whose emission characteristics can be tuned by altering their thickness. The resulting nanoplatelets are about 300 times thinner than the perovskite films conventionally used in the fabrication of solar cells.
Despite their large surface area, these platelets emitted an intense blue luminescence, and the properties exhibited by these minuscule particles were deemed inexplicable in the context of classical physics. The scientists state that they can be accounted for only by the laws of quantum physics, as confirmed by theoretical calculations carried out by the team.
Moreover, not only could platelets of varying thickness be produced in a controlled manner by modifying the conditions of their synthesis, these changes also resulted in striking alterations in their optical properties: In fact, the light emitted by the perovskite nanoplatelets was found to depend on their thickness. By adding layers to the crystal lattice, the researchers were able to progressively change the color of the emitted photoluminescence from violet to blue and finally to green.
The team now hopes to extend the tunability of the radiation emitted by their perovskite nanocrystals over the entire visible range and beyond. This would make it possible to manufacture energy-efficient and economical LEDs that radiate light of virtually any desired color, and these novel nanoplatelets are also ideally suited for use in lasers.