Nucleation Temperature‐Dependent Synthesis of Polytypic CuInSe₂ Nanostructures with Variable Tetrapod‐Like and Core‐Shell Morphologies

Abstract Despite the merits of low toxicity and light absorption/emission in the near‐infrared spectral range, synthesis of polytypic CuInSe₂ nanocrystals is challenging. Herein, we demonstrate a synthetic approach to produce polytypic CuInSe₂ nanocrystals with variable morphologies, such as tetrapods with short or long arms; core/shell nanostructures; and hollow structures formed due to the Kirkendale effect. All polytypic CuInSe₂ nanostructures realized in this work consist of a core with a chalcopyrite phase, and arms or shells with a wurtzite phase. With increasing nucleation temperature, the size of the chalcopyrite core gradually increases, while the arms or shells become smaller/thinner, due to the competition between nucleation and growth. This work provides guidance towards the synthesis of polytypic CuInSe₂ nanocrystals with tunable size and morphology, and enriches the family of available CuInSe₂ nanostructures.