1 research outputs found
Boosting Tunable Blue Luminescence of Halide Perovskite Nanoplatelets through Postsynthetic Surface Trap Repair
The
easily tunable emission of halide perovskite nanocrystals throughout
the visible spectrum makes them an extremely promising material for
light-emitting applications. Whereas high quantum yields and long-term
colloidal stability have already been achieved for nanocrystals emitting
in the red and green spectral range, the blue region currently lags
behind with low quantum yields, broad emission profiles, and insufficient
colloidal stability. In this work, we present a facile synthetic approach
for obtaining two-dimensional CsPbBr<sub>3</sub> nanoplatelets with
monolayer-precise control over their thickness, resulting in sharp
photoluminescence and electroluminescence peaks with a tunable emission
wavelength between 432 and 497 nm due to quantum confinement. Subsequent
addition of a PbBr<sub>2</sub>-ligand solution repairs surface defects
likely stemming from bromide and lead vacancies in a subensemble of
weakly emissive nanoplatelets. The overall photoluminescence quantum
yield of the blue-emissive colloidal dispersions is consequently enhanced
up to a value of 73 ± 2%. Transient optical spectroscopy measurements
focusing on the excitonic resonances further confirm the proposed
repair process. Additionally, the high stability of these nanoplatelets
in films and to prolonged ultraviolet light exposure is shown