While green and red perovskite emitters are well established in the community, blue emitters still face some challenges due to their lack of stability owing to Cl-anions or poor optical performance showing in low photoluminescence quantum yields. Our group works with a recently developed synthesis to obtain perovskite nanoplatelets with a distinct thickness of 1.2 to 3.6 nm.
Here, different emission wavelengths from green to deep blue can be achieved by taking advantage of strong quantum confinement effects. With postsynthetic treatments with ions and organic molecules we can increase both, the stability and efficiency of the nanoplatelets. Additionally, we are constantly improving the synthesis procedure to obtain better nanocrystals and to incorporate them into optoelectronic devices. The synthesis itself is a ligand-assisted reprecipitation process (LARP) and can be conducted at room temperature and ambient conditions.
The use of quantum confined nanoplatelets offers new possibilities for optoelectronic devices. Their narrow and bright emission is favorable for application in light emitting diodes (LEDs). In addition, by combining different nanoplatelet thicknesses it is possible to build perovskite-heterostructures. As recently shown by our group, energy transfer between nanoplatelets is highly efficient and could lead to the realization of energy transfer cascades.