Bright and Uniform Green Light Emitting InP/ZnSe/ZnS Quantum Dots for Wide Color Gamut Displays

Abstract

There is an urgent demand to improve the efficiency and the color purity of the environment-friendly quantum dots (QDs), which can be used in wide color gamut (WCG) displays. In this study, we optimized the reaction conditions for the InP core synthesis and the ZnSe/ZnS multishell growth on the core. As a result, remarkable improvements were achieved in the photoluminescence quantum yield (PL QY, 95%) and the full width at half-maximum (fwhm, 36 nm), with perfectly matched wavelength (528 nm) for the green color in WCG displays. Injection of the phosphorus precursor at a mild temperature during the InP core synthesis reduced the size distribution of the core to 12%, and the shell growth performed at a high temperature significantly enhanced the crystallinity of the thick passivating layer. We also investigated the photophysical properties, particularly the energy trap distributions and trap state emissions of the InP-based QDs with different shell structures. The time-resolved and temperature-dependent PL spectra clearly indicated that the well-passivated InP/ZnSe/ZnS QDs showed nearly trap-free emissions over a wide temperature range (77–297 K). Also, the on- and off-time probability on single QD blinking and Auger ionization efficiencies also showed that these QDs were hardly affected by the surface traps.

Surface passivation extends single and biexciton lifetimes of InP quantum dots

“…Meanwhile, InP, a binary III-V semiconductor, is considered as one of the most promising environmentally friendly nanocrystals. With a bulk bandgap at 1.35 eV and suitable bandedge energies (CB: À3.85 eV and VB: À5.2 eV), 15 InP QDs can be tuned to absorb a wide range of photoenergies and see emerging applications in solar cells, 16,17 LEDs, 7,18 and photocatalytic reactions. 8,10 However, despite the desirable material properties, early studies 19,20 have shown that these materials contain a large density of traps states (Scheme 1a), evidenced by their low photoluminescence (PL) quantum efficiencies.…”

Unprecedented surface stabilized InP quantum dots with bidentate ligands

“…Thus far, compared to CdSe, InP has many limitations with regards to various aspects, for example, wide emission spectral line-width, and low QY and stability; a large amount of research has been done to address these problems. As a result, some characteristics of InP have improved signicantly, [17][18][19] while some still need to be improved. Nevertheless, there are still problems associated with replicating the characteristics of CdSe.…”

Highly qualified InP based QDs through a temperature controlled ZnSe shell coating process and their DFT calculations

“…[13][14][15] In terms of the FWHM aspect, green has a FWHM of approximately 40-45 nm on average, and 36 nm for the narrowest emission. 16 Some studies have been conducted to improve the photoluminescence (PL) line narrowing of InPbased QDs. For example, Li et al controlled the reaction temperature and used new precursors, which resulted in a quantum yield (QY) of 70% and FWHM of 45 nm in the green region.…”