Negative Trion Auger Recombination in Highly Luminescent InP/ZnSe/ZnS Quantum Dots

Auger recombination [12,13] and energy transfer between QDs in films, which is required in QD-light emitting diode (LED) applications. [14][15][16][17] Second is the etching of an oxidized core prior to shell growth to prevent interfacial oxidation. [7,18,19] Finally, smoothing of core/shell interface by matching a shell with a similar lattice constant can be applied to avoid the generation of defect sites. [20,21] We synthesize InP/ZnSe/ZnS QDs having a thick ZnSe shell (with 8 monolayers). The QDs with thick ZnSe shell are effective for reducing energy transfer between neighboring QDs in respect of QD-LED applications. In this study, we present a simple but highly effective strategy to modulate the InP/ZnSe/ZnS QD shapes by controlling the shell reaction temperatures. The strategy of increasing the ZnSe shell-grown temperature accelerated the rates of shell growth. The synthesized two structures showed differences in morphology; one is a QD with an irregular shell (iQD), and the other is one with a regular isotropic shell (rQD). Especially, the rQDs have significantly improved the photoluminescence (PL) quantum yield (QY). Since the correlation between morphology modification and photophysical properties has been unexplored for InP-based core/shell QDs to the best of our knowledge, we scrutinized the ZnSe shell crystalline structures and PL properties of the InP/ZnSe/ZnS QDs with different shapes.Ensemble-averaged measurements have often been used to evaluate QD photophysical properties, [22][23][24][25] but they tend to overlook the nature of an individual QD or inter-dot interactions. To fully understand the charge carrier dynamics depending on the QD morphology, we investigated the photophysical properties of QDs on both ensemble and single dot levels. As a result, it was found that the shape-dependent QD PL efficiencies are governed by charge trapping dynamics. The ZnSe crystalline structure analyses verified that the fast ZnSe reaction on the InP core reduced facet-selective growth and eliminated stacking faults. Thus, we have concluded that the enhancement of PL QY in isotropic QDs has resulted from the removal of stacking faults. The pump energy-dependent transient absorption (TA) dynamics showed that the hot hole trapping was considerably suppressed in the iQDs. This spectroscopic evidence supports the supposition that the stacking faults in the InP/ZnSe crystalline structures act as structural defects to trap hot charge carriers. In this study, we provide a spectroscopic insight into the shape-dependent PL efficiency of InP-based QDs and the correlation between the hole trapping dynamics and the structural defects.Isotropic InP/ZnSe/ZnS quantum dots (QDs) are prepared at a high reaction temperature, which facilitates ZnSe shell growth on random facets of the InP core. Fast crystal growth enables stacking faults elimination, which induces anisotropic growth, and as a result, improves the photoluminescence (PL) quantum yield by nearly 20%. Herein, the effect of the QD morphology on photophysical properti...

show abstract

“…

…”

mentioning

confidence: 99%

Tuning Hot Carrier Dynamics of InP/ZnSe/ZnS Quantum Dots by Shell Morphology Control

Park

Won

Han

et al. 2021

Small

Self Cite

View full text Add to dashboard Cite

show abstract

“…For instance, in the case of the ZnSeS inner shell, ZnSe-richer composition induces an increasing exciton delocalization, leading to an E g lowering due to the reduced quantum confinements. 6,9 Meanwhile, given ZnSe as the inner shell, its increasing thickness manifests the same effect as above, 22,23 even though the degree of exciton delocalization is dependent on InP core size, i.e. , green- versus red-emissive cores.…”

Section: Resultsmentioning

confidence: 76%

“…In the case of InP heterostructured QDs with double shells such as ZnSe/ZnS and ZnSeS/ZnS, their emission bandwidth is dependent on the composition 8,9,19 and thickness of the inner shell. 21–23 Given the identical inner shell ( i.e. , ZnSe) for both InBr 3 - and InCl 3 -based red QDs above, the equality in bandwidth may point to the growth of the ZnSe inner shell with the same thickness as well as the same degree of core size monodispersity.…”

Section: Resultsmentioning

confidence: 99%

“…Auger recombination, the most detrimental factor in limiting QLED performance, can be highly sensitive particularly to the thickness of the inner shell in the InP/ZnSe/ZnS QD system. 10,21,22 Thickening ZnSe inner shell was shown to be beneficial in slowing down the Auger rate of particularly negative trion by delocalizing an electron and thus weakening intercarrier Coulombic interaction, 21,22 by which the chance of multi-carrier radiative recombination becomes enhanced toward higher device efficiency.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Aminophosphine-derived, high-quality red-emissive InP quantum dots by the use of an unconventional in halide

et al. 2022

View full text Add to dashboard Cite

show abstract

“…In addition, the InP/ZnS core/shell structure inevitably leads to the inter-doping of core/shell structure, because the III and V group atoms are easily doped into the II–VI atoms [ 69 , 70 ]. Both oxidation defects and component doping could generate a large number of surface traps at the InP/ZnS interface, as these will cause energy losses, such as Förster resonance energy transfer (FRET) and Auger recombination (AR) [ 6 , 71 ]. To suppress the non-radiative progress, double-shell QDs were fabricated [ 72 ].…”

Section: Influence Of Core/shell Structure On Performance Of Inp Qledsmentioning

confidence: 99%

Advances and Challenges in Heavy-Metal-Free InP Quantum Dot Light-Emitting Diodes

et al. 2022

View full text Add to dashboard Cite

Light-emitting diodes based on colloidal quantum dots (QLEDs) show a good prospect in commercial application due to their narrow spectral linewidths, wide color range, excellent luminance efficiency, and long operating lifetime. However, the toxicity of heavy-metal elements, such as Cd-based QLEDs or Pb-based perovskite QLEDs, with excellent performance, will inevitably pose a serious threat to people’s health and the environment. Among heavy-metal-free materials, InP quantum dots (QDs) have been paid special attention, because of their wide emission, which can, in principle, be tuned throughout the whole visible and near-infrared range by changing their size, and InP QDs are generally regarded as one of the most promising materials for heavy-metal-free QLEDs for the next generation displays and solid-state lighting. In this review, the great progress of QLEDs, based on the fundamental structure and photophysical properties of InP QDs, is illustrated systematically. In addition, the remarkable achievements of QLEDs, based on their modification of materials, such as ligands exchange of InP QDs, and the optimization of the charge transport layer, are summarized. Finally, an outlook is shown about the challenge faced by QLED, as well as possible pathway to enhancing the device performance. This review provides an overview of the recent developments of InP QLED applications and outlines the challenges for achieving the high-performance devices.

show abstract

Negative Trion Auger Recombination in Highly Luminescent InP/ZnSe/ZnS Quantum Dots

Cited by 42 publications

References 46 publications

Tuning Hot Carrier Dynamics of InP/ZnSe/ZnS Quantum Dots by Shell Morphology Control

Tuning Hot Carrier Dynamics of InP/ZnSe/ZnS Quantum Dots by Shell Morphology Control

Aminophosphine-derived, high-quality red-emissive InP quantum dots by the use of an unconventional in halide

Advances and Challenges in Heavy-Metal-Free InP Quantum Dot Light-Emitting Diodes

Contact Info

Product

Resources

About