Study of the Interfacial Oxidation of InP Quantum Dots Synthesized from Tris(dimethylamino)phosphine

Abstract

InP quantum dots (QDs) are the most competitive in terms of environmentally friendly QDs. However, the synthesis of InP QDs requires breakthroughs in low-cost and safe phosphorus precursors such as tri(dimethylamino)phosphine [(DMA) 3 P]. It is found that even if the oxygen is completely avoided, there are still oxidation state defects at the core/shell interface of InP QDs. Herein, the record-breaking (DMA) 3 P-based red InP QDs were synthesized with the assist of HF processing to eliminate the InPO x defect and improve the fluorescence efficiency. The maximum photoluminescence quantum yield was 97.7%, which is the highest of the red InP QDs synthesized by the aminophosphine. The external quantum efficiency and brightness of the QD light-emitting diode device are also improved accordingly from 0.6% and 1276 cd•m −2 to 3.5% and 2355 cd•m −2 , respectively.

Surface Passivation toward Multiple Inherent Dangling Bonds in Indium Phosphide Quantum Dots

“…The previously reported results reveal that excess PF 6 – ions can form the In–PF 6 bond, which supports the shift of the In 3d peak to a higher binding energy. However, in our work, the down-shifting of In 3d binding energy to enhanced electron cloud density of the In atom due to a substantial electron-donating impact of NH 4 + and weak electronegativity of PF 6 – ions . The P 2p spectra (Figure b) provide evidence of the presence of two chemical environments for phosphorus atoms.…”

Interface defects repair of core/shell quantum dots through halide ion penetration

“…† Typically, the shorter component (s 1 ) of the uorescence lifetime is associated with band-edge transition emission, while the longer component (s 2 ) is linked to defect-related emission. 40 It is observed that the band-edge transition portions (s 1 %) signicantly increase in ZnX 2 treated QDs. Specically, the band-edge transition portion of ZnBr 2 treated QDs improved from 50.1% to 79.2% compared with untreated QDs.…”

Tuning the Shades of Red Emission in InP/ZnSe/ZnS Nanocrystals with Narrow Full Width for Fabrication of Light-Emitting Diodes

“…In this regard, various attempts have been carried out with either one-pot methods like the use of zinc-oxo clusters, a thick intermediate ZnSe (or ZnMnS) shell layer, , hydrofluoric acid (HF), and ligand-assisted post-treatment or two-pot methods like ZnF 2 -assisted synthesis, aminophosphine-derived halide-assisted synthesis, and stoichiometry control . Several well-established studies have also focused on combining these different chemical tricks to reach stable, intense, pure-red emissions for better device performance. − Among these strategies, using the benefits of surface fluorination to remove the oxidation states on the surfaces of InP core NCs is a promising method, usually done with HF. − The common colloidal synthesis approach employed in all of these studies is hot-injection, which acts as a powerful tool that provides nice control over the physicochemical properties of three-dimensionally confined quantum dots (QDs). The experimental parameters in this method can be easily tuned to induce a change to a particular target, such as a blue- or red-shift in the optical features, along with the possibility of large-scale synthesis.…”

“…Currently, the interest in one-pot colloidal methods is greater due to their simplicity, better reproducibility, and faster reactions. However, for almost all of the QDs created with these methods (even the highly luminescent QDs), their PL signals are located at wavelengths ≤620 nm or their fwhm is ≥50 nm, ,,,,− which both reduce the required red color purity for high-performance devices. As mentioned previously, this challenge is more dominant for far-red emissions at longer wavelengths, typically >640 nm.…”