Wurtzite InAs Nanocrystals with Short-Wavelength Infrared Emission Synthesized through the Cation Exchange of Cu₃As Nanocrystals

Colloidal InAs nanocrystals (NCs) are among the most promising light emitters in the short-wavelength infrared (SWIR) range. These InAs NCs are eligible to crystalize into two distinct phases, i.e., cubic zinc-blende phase and metastable hexagonal wurtzite phase. However, InAs NCs directly produced through molecular precursors unanimously exhibited zinc-blende structure, and the synthesis of their wurtzite counterparts has never been achieved. Herein, we report the first successful synthesis of high-quality wurtzite InAs NCs, which show bright SWIR photoluminescence with a tunable emission peak and high quantum yield of up to ∼37%. This is achieved by the cation exchange of Cu 3 As NCs with controllable size and morphology, followed by the growth of inorganic passivation layers to eliminate the possible surface trap centers. We further expand the synthesis route to wurtzite ternary InAs 0.5 P 0.5 NCs with quasi-one dimensional confinement, which exhibit polarized SWIR emission, exploring the potential of these anisotropic NCs as efficient polarized light emitters.