Abstract: The present disclosure provides a method for facet-selective passivation on each crystal facet of colloidal nanocrystals via solution-phase ligand exchange process, thereby providing highly-passivated and colloidally-stable nanocrystal inks. This ligand exchange strategy separately addresses polar and non-polar facets precluding from deleterious nanocrystal aggregation in the colloid. The method involves the introduction of alkali metal organic complexes during metal halide conventional solution exchanges, and one specific example is Na+·Ac?. Alkali metal ions stabilize and passivate non polar facets whereas polar facets are passivated through metal halides. This strategy leads to a significant decrease in nanocrystal aggregation during and after ligand exchange, and to improved photophysical properties stemming from this. The resulting nanocrystal solid films exhibit improved stability, retain their absorption features, and have a minimized Stokes shift.

Abstract: The present disclosure provides a method for facet-selective passivation on each crystal facet of colloidal nanocrystals via solution-phase ligand exchange process, thereby providing highly-passivated and colloidally-stable nanocrystal inks. This ligand exchange strategy separately addresses polar and non-polar facets precluding from deleterious nanocrystal aggregation in the colloid. The method involves the introduction of alkali metal organic complexes during metal halide conventional solution exchanges, and one specific example is Na+.Ac?. Alkali metal ions stabilize and passivate non polar facets whereas polar facets are passivated through metal halides. This strategy leads to a significant decrease in nanocrystal aggregation during and after ligand exchange, and to improved photophysical properties stemming from this. The resulting nanocrystal solid films exhibit improved stability, retain their absorption features, and have a minimized Stokes shift.

Abstract: An organic solar cell is provided. The organic solar cell includes a photoactive layer in which a low molecular weight conjugated compound as a first organic semiconductor material is mixed with an appropriate amount of a second organic semiconductor material. The first organic semiconductor material includes both electron donors and electron acceptors. The presence of the electron donors and the electron acceptors in the first organic semiconductor material improves the morphology of the photoactive layer, leading to high efficiency of the organic solar cell.

Abstract: An organic solar cell is provided. The organic solar cell includes a photoactive layer in which a low molecular weight conjugated compound as a first organic semiconductor material is mixed with an appropriate amount of a second organic semiconductor material. The first organic semiconductor material includes both electron donors and electron acceptors. The presence of the electron donors and the electron acceptors in the first organic semiconductor material improves the morphology of the photoactive layer, leading to high efficiency of the organic solar cell.