Tuesday, 10 November, 2015

Quantum Size Effect in Organometal Halide Perovskite Nanoplatelets

J. Sichert, Y. Tong, N. Mutz, M. Vollmer, S. Fischer, K. Milowska, R. Cortadella, B. Nickel, C. Cardenas-Daw, J. Stolarczyk, A. Urban, J. Feldmann -
NANO LETTERS, 15 (10):6521-6527 (2015)

Organometal halide perovskites have recently emerged displaying a huge potential for not only photovoltaic, but also light emitting applications. Exploiting the optical properties of specifically tailored perovskite nanocrystals could greatly enhance the efficiency and functionality of applications based on this material. In this study, we investigate the quantum size effect in colloidal organometal halide perovskite nanoplatelets. By tuning the ratio of the organic cations used, we can control the thickness and consequently the photoluminescence emission of the platelets. Quantum mechanical calculations match well with the experimental values. We find that not only do the properties of the perovsidte, but also those of the organic ligands play an important role. Stacking of nanoplatelets leads to the formation of minibands, further shifting the bandgap energies. In addition, we find a large exciton binding energy of up to several hundreds of meV for nanoplatelets thinner tha

 n three unit cells, partially counteracting the blueshift induced by quantum confinement.

Understanding of the quantum size effects in perovsldte nanoplatelets and the ability to tune them provide an additional method with which to manipulate the optical properties of organometal halide perovsldtes.

Article on journal´s webpage