Tertiary amine oxides as perovskite nanocrystal ligands and components of polymeric nanocomposites

As a class of semiconductor nanocrystals that exhibit high photoluminescence quantum yield (PLQY) at tunable wavelengths, perovskite nanocrystals (PNCs) are attractive candidates for optoelectronic and light-emitting devices. However, attempts to optimize PNC integration into such applications suffer from PNC instability and loss of PL over time. Here, we describe the impact of organic and polymeric N-oxides when used in conjunction with PNCs, whereby a significant increase in PNC quantum yield is observed in solution, and stable PL emission is obtained in polymeric nanocomposites. Specifically, when using aliphatic N-oxides in ligand exchange with CsPbBr3 PNCs in solution, a substantial boost in PNC brightness is observed (similar to 40% or more PLQY increase), followed by an alteration of the perovskite chemistry. When N-oxide substituents are positioned pendent to a poly(n-butyl methacrylate) backbone, the optically clear flexible nanocomposite films obtained have bright PL emission and maintain optical clarity for months. X-ray diffraction is useful for characterizing the PNC crystalline structure following exposure to aliphatic N-oxides, while electron microscopy (EM) and small-angle X-ray scattering (SAXS) measurements of the PNC-polymer nanocomposites show this polymeric N-oxide platform to cleanly disperse PNCs in flexible polymer films.