Pushing the Band Gap Envelope of Quasi-Type II Heterostructured Nanocrystals to Blue: ZnSe/ZnSe1-XTeX/ZnSe Spherical Quantum Wells
Electronic features and photophysical properties of ZnSe/ZnSe1-XTeX/ZnSe NCs. (a) Band gap energy of ZnSe/ZnSe1-XTeX/ZnSe NCs with varying Te contents (, 0.10, 0.20, 0.33, and 0.50) and ZnSe shell thicknesses (, 1.2, 1.8, and 2.4 nm). The bulk band gap energy of ZnSe (violet circle at the left axis) and ZnTe (red circle at the right axis) is displayed for comparison. (b) The lowest quantized energy states for electron (1Se) and hole (1Sh) of ZnSe ()/ZnSe1-XTeX ()/ZnSe () NCs with varying Te contents. 1Sh and 1Se of NCs are obtained from ultraviolet photoelectron spectroscopy in chorus with UV-Vis absorption spectroscopy. (c) Calculated electron-hole overlap integrals of ZnSe ()/ZnSe1-XTeX ()/ZnSe NCs with varying Te ratios and ZnSe shell thicknesses. (d) Radial probability of electron and hole wave functions and (e) PL decay dynamics of ZnSe ()/ZnSe0.66Te0.33 ()/ZnSe NCs with varying ZnSe shell thicknesses (). The inset shows radiative decay rates of single exciton () and electron and hole overlap integrals () of each sample.