With tunable emission in the full
visible region, the ecofriendly
InP quantum dots (QDs) show unique application prospects in light-emitting
devices. At present, InP QDs suffer from wide-bandwidth emission,
especially for electroluminescence (EL), which hinders their applications
in high-performance display devices. Here, we report a facile one-pot
synthesis of narrow-bandwidth InP/ZnSeS/ZnS QDs using a safe phosphorus
source of tris(dimethylamino)phosphine, in which the ZnSeS inner-shell
layer is formed via temperature-gradient solution growth from 240
to 280 °C. The synthesized green QDs have a high photoluminescence
quantum yield (PLQY) of 91% and full width at half-maximum (fwhm)
of 36 nm. Moreover, the resultant quantum dot light-emitting devices
(QLEDs) also show a narrow fwhm of 42 nm, which is the narrowest emission
of green InP QLEDs based on a safe phosphorus source reported so far.
Further modulation of the electron injection into the device by inserting
a thin layer of lithium fluoride results in a peak external quantum
efficiency of 5.56%.