Construction stable and highly bright photoluminescence of Ag and Mn codoped Zn-In-Se nanocrystals toward wLEDs application

Highlights: • dQDs are obtained via the facile one-pot hot-injection synthetic method. • By adjusting the doping concentrations, the efficient white light could be achieved. • The coating shell ZnSe can effectively enhance the PL quantum yield (QY) and stability. • Selenide dQDs applied in QDLEDs as singly emitter exhibit good performance. -- Abstract: Quantum dots (QDs) with composition/size dependent optoelectronic properties have been regarded as emerging materials to be potentially applied in photoelectric fields. For QDs based light emitting diodes (QDLEDs), the efficient devices are still focused on toxic binary QDs containing heavy metals. Herein, a series of less-toxic and emission color tunable Ag, Mn codoped Zn-In-Se optimized dQDs are synthesized and detailed studied via the facile low-cost one-pot hot-injection synthetic method using Se in octadecene as 'green' Se source. After coating a thick ZnSe shell (~7.9 monolayers) on the core dQDs, higher photoluminescence (PL) quantum yield (QY) up to 68% was achieved and higher emission efficiency was retained even when the initially oil-soluble QDs are transferred into aqueous media by ligand replacement. Furthermore, both photostability and thermal stability of the core/shell dQDs were significantly enhanced as compared with those of core dQDs due to the suppressed surface defects resulting from the passivation of the dense ZnSe layers. The dQDs are further applied in QDLEDs as singly emitter and exhibited good performance with color rendering index (CRI) of 79, CIE coordinates of (0.368, 0.327), CCT of 4105 K and maximum luminance of 180 cd m⁻², indicating that the studied core/shell dQDs could be a potential candidate in QD-based lighting or solid-state lighting as a single color-converting materials.