Synthesis and optical properties of water-soluble CdTe 1−x Se x quantum dots with ultra-long fluorescence lifetime

Abstract Water-soluble ternary-alloyed CdTe 1− x Se x quantum dots (QDs) have been synthesized via a simple one-pot approach in aqueous phase. The as-prepared CdTe 1− x Se x QDs show good crystallinity, excellent monodispersity, and a narrow size distribution with average size of 3.0 nm. Lattice parameters and band gaps of the ternary-alloyed CdTe 1− x Se x (0 ≤  x x ). By tuning composition, the photoluminescence (PL) emission wavelength of CdTe 1− x Se x can cover from 528.9 to 689.3 nm, and gradually moved to longer wavelengths with a decrease content of Se ( x ). The lifetime of CdTe 1− x Se x QDs is decreased gradually with the Se content ( x ) augment, attributing to the decreasing lattice spacing resulting from substitution of the larger Te atoms with the smaller Se atoms, bringing about a incremental plasmonic coupling effect at smaller inter-lattice fluorophore distance. However, the as-prepared CdTe 1− x Se x QDs (0 ≤  x 80 ns with the maximum lifetime up to 174.64 ns. The longer life is good for the application of photoelectric conversion, fluorescent biomedical imaging and detecting.