Synthesis of green rod-in-rod CdSeS/CdZnS/ZnS nanorods with high quantum yield and linear polarization

Nanorods (NRs) hold promise for surpassing the theoretical external quantum efficiency limit of light-emitting diodes (LEDs) based on spherical quantum dots (QDs) due to their linearly polarized emission and high photon out-coupling efficiency. Compared with the most studied dot-in-rod NRs, rod-in-rod NRs have higher degree of polarization. However, due to the difficulties in achieving uniform NR seeds, synthesizing rod-in-rod NRs that cover the entire visible spectrum remains a significant challenge, especially for green and blue ones. In this study, high-quality and uniformly sized green CdSeS NRs were successfully synthesized by systematically optimizing the S/Se ratio, the nucleation temperature and the amount of ligand. Based on these high-quality NR seeds, CdSeS/CdZnS/ZnS core–shell NRs were further prepared with narrow emission bandwidths (28 nm at 540 nm), high photoluminescence (PL) quantum yield (75%), and high linear polarization (the PL anisotropy (r) = 0.3). This study provides a new possibility for the application of NRs in LEDs, lasers, and other optoelectronic devices.