Zinc Carboxylate Surface Passivation for Enhanced Optical Properties of In(Zn)P Colloidal Quantum Dots

Abstract

Indium phosphide (InP) colloidal quantum dots (CQDs) have generated great interest as next-generation light-emitting materials owing to their narrow emission spectra and environment-friendly components. The minimized surface defects is essential to achieve narrow full-width at half-maximum (FWHM) and high photoluminescence quantum yield (PLQY). However, InP CQDs are readily oxidized in ambient condition, which results in formation of oxidation defect states on the surface of InP CQDs. Herein, we introduce a strategy to successfully passivate the surface defects of InP core by zinc complexes. The zinc carboxylates passivation reduces FWHM of InP CQDs from 130 nm to 70 nm and increases PLQY from 1% to 14% without shelling. Furthermore, the photoluminescence (PL) peak has shifted from 670 nm to 510 nm with an increase of zinc carboxylates passivation, which suggests that excessive zinc carboxylates functions as a size-regulating reagent in the synthesis.

High-brightness green InP-based QLEDs enabled by in-situ passivating core surface with zinc myristate

“…Herein, we added ZnMy 2 at 270 • C and adjusted its concentration (figure S1, supporting information), which could adjust the nucleation and eliminate surface oxidation. Choi et al reported that the introduction of ZnMy 2 might produce Zn-P complex, which acted as phosphine reservoir to improve the monodisperse in the growth process [29]. As shown in figure 1(a), compared with the InP cores without ZnMy 2 , the InP cores with ZnMy 2 have an increased absorption valley/peak ratio (Vd) of 0.5 and a narrower FWHM of 35 nm, indicating their more uniform size distribution.…”

Editorial for the Special Issue on Quantum Dots Frontiers

“…The main challenge remaining is achieving efficient and stable QLED with blue emission. Notably, the QDs for lighting and display applications are mainly referred to CdSe QDs, InP QDs (mostly merged as core-shell structured QDs, and the alloyed QDs) [ 3 , 5 , 6 , 7 ], and perovskite nanocrystals [ 8 , 9 , 10 ].…”

“…Specifically, for QDs in material science, Hu et al investigated the properties of doped perovskite QDs with mixed-A-cations [ 10 ]. Moreover, Yoo et al improved the efficiency of cadmium-free QDs via advanced surface passivation [ 6 ]. Halim et al investigated the electron–phonon coupling mechanism of PbS QDs and PbS/MnTe QDs by tracking their temperature-dependent PL spectra [ 17 ].…”