Gradient Alloy CdSe/CdZnS Nanorods as Polarized Room-Temperature Single-Photon Sources
Qingya Wang, Yicheng Zeng, Min Li, Yingying Sun, Xiaoshuai Zhang, Zhen Guan, Yuxian Liang, Jiakang Tang, Xiaoya Sun, Alexey Zhukov, Jing Wei, Fangze Liu, Hongbo LiAbstract
Colloidal semiconductor nanorods (NRs) are promising room-temperature single-photon sources because of their solution processability, tunable optical properties, and intrinsically linearly polarized emission. However, simultaneously achieving high photoluminescence quantum yield (PLQY), strong polarization, and high-purity single-photon emission remains challenging in conventional binary-shell NRs due to the competing requirements of exciton confinement and core/shell lattice–strain management. Here, we report CdSe/CdZnS gradient alloy core/shell NRs with tunable aspect ratios to address these issues. The gradient alloy shell provides a smooth lattice transition, reducing interfacial strain while maintaining effective exciton confinement. At an aspect ratio of 3.8, the NRs achieve a near-unity PLQY, a high linear polarization (0.76), fully suppressed blinking, and excellent single-photon purity [g2(0) = 0.068]. Increasing the aspect ratio to 13 reduces the PLQY and enhances blinking, with power-law analysis revealing aspect-ratio-dependent on/off-state dynamics. These results demonstrate the potential of alloy-shell NRs as high-brightness, room-temperature single-photon emitters.