| Abstract: | Colloidal Pb Se nanocrystals(NCs) have gained considerable attention due to their efficient carrier multiplication and emissions across near-infrared and short-wavelength infrared spectral ranges. However, the fast degradation of colloidal Pb Se NCs in ambient conditions hampers their widespread applications in infrared optoelectronics. It is well-known that the inorganic thick-shell over core improves the stability of NCs. Here, we present the synthesis of Pb Se/Pb S core/shell NCs showing wide spectral tunability, in which the molar ratio of lead(Pb) and sulfur(S) precursors, and the concentration of sulfur and Pb Se NCs in solvent have a significant effect on the efficient Pb S shell growth. The infrared light-emitting diodes(IR-LEDs) fabricated with the Pb Se/Pb S core/shell NCs exhibit an external quantum efficiency(EQE) of 1.3 % at 1280 nm. The ligand exchange to optimize the distance between NCs and chloride treatment are important processes for achieving high performance on Pb Se/Pb S NC-LEDs. Our results provide evidence for the promising potential of Pb Se/Pb S NCs over the wide range of infrared optoelectronic applications. |
