Colloidal perovskite quantum dots (PQDs), in particular those made of full-inorganic CsPbX3 (X = Cl, Br, I), have attracted tremendous attention over the past few years, due to their excellent optoelectronic properties and the promise they offer in applications that include light-emitting and photovoltaic devices. However, such potential is hampered by their very limited steric stability and rapid loss of fluorescence during processing. These problems are caused by a combination of the ionic nature of the cores and fast desorption of the surface capping ligands. To address those problems, we have developed a ligand exchange strategy based on substituting the native cap with a multi-functional polymer where surface coordination is driven by electrostatic interactions (using zwitterion moieties). The ligands were synthesized by installing a stoichiometric mixture of zwitterion and solubilizing motifs on a poly (isobutylene-alt-maleic anhydride), PIMA, via nucleophilic addition reaction. We find that this coting exhibits strong binding affinity to the ionic surfaces of the PQDs, and imparts enhanced colloidal stability of the nanocrystals over a broad range of solvents, including those with high polarity. As such, dispersions of PQDs in several alcohols, with preserved cubic crystal structure and superior photophysical properties (namely, narrow-band emission and high photoluminescence quantum yield) have been prepared and tested.

Improving the stability of CsPbX3 (X=Cl, Br, I) perovskite quantum dots via ligand design

2019 Spring National Meeting

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