Lead halide perovskite nanocrystals (NCs) are emerging as an exciting class of colloidal semiconductors owing to their defect tolerance that enables intense, narrow photoluminescence emission without the need for surface passivation steps. Despite this, these NCs suffer from a lack of chemical (and thus optical) stability, and even all-inorganic cesium lead halides CsPbX3 (X = Cl, Br, I) exhibit a relatively fragile ionic crystal in polar solvents, as well as weakly bound ligand shells. As such, new methods are needed to shield perovskite NCs from degradation, which we are working on from the standpoints of ammonium bromide (ω-NH3Br) terminated polymers as halide precursors for NC synthesis, as well as polymer zwitterions for post-synthetic ligand exchange. This lecture will describe our use of such NC preparation and composite film formation techniques, including NCs assembly into optically transparent nanocomposite films utilizing conjugated polymers as ligands and/or involving NC binding by zwitterionic pendent groups. Nanocomposite structures resulting from these methods retain their photoluminescence emission for months, in some cases even after submerging in water. Looking forward, current investigations into polymer microstructure, zwitterion chemistry, and device fabrication are under investigation with the intention of gaining fundamental insights into perovskite NC structure, chemistry, and stability.

Nanocomposite films and assemblies using functional polymers and perovskite nanocrystals

ACS Fall 2021

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