Polytypic Zn-(In,Ga)-Se Nanocrystals with Tunable Emission.

Sun, Zhaohong; Baluyot-Reyes, Nina; Zamarripa, Karla; Djurovich, Peter I; Thompson, Mark E; Brutchey, Richard L · Nano Lett · 2025

basic_science · Level V

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Abstract

While the polymorphism of chalcopyrite semiconductors has been widely studied, the wurtzite analogues of defect-chalcopyrite II-III<sub>2</sub>-VI<sub>4</sub> compositions, such as Zn(In,Ga)<sub>2</sub>(S,Se)<sub>4</sub>, remain underexplored. Here, we report the synthesis of polytypic Zn-(In,Ga)-Se multipods via cation exchange using ZnSe as a template. With zinc-blende cores and wurtzite arms elongated along the hexagonal <i>c</i>-axis, the multipods retain the structure and morphology of the ZnSe template. Optical characterization reveals composition-dependent absorption and photoluminescence, tunable from the visible to the near-infrared region, with spectral features distinct from those of previously reported defect-chalcopyrite structures. Temperature-dependent measurements demonstrate strong emission at cryogenic temperatures, which is quenched near room temperature due to thermally activated nonradiative processes. We illustrate the use of ZnSe as a platform for cation exchange toward wurtzite multinary chalcogenides, unlocking access to novel structures with colorful optical properties.