Engineering Core Size of InP Quantum Dot with Incipient ZnS for Blue Emission

Abstract

Blue indium phosphide quantum dot (InP QD) is an emerging colloidal semiconductor nanocrystal, considered as a promising next‐generation photoactive material for light‐emitting purposes. Despite the tremendous progress in blue InP QDs, the synthetic method for tailoring InP core size to realize the blue‐emissive QDs still lags behind. This work suggests a synthetic method for blue‐emitting InP QDs by engineering the core size with an incipient ZnS (i‐ZnS) shell. The formation of i‐ZnS complexes, before the tris(trimethylsilyl)phosphine injection (e.g., before core growth process), restrains the overgrowth of InP nuclei by rapidly forming a ZnS shell on its surface, thereby resulting in further dwarfed InP cores. With additional ZnS shell coating, the blue QDs exhibit a photoluminescence quantum yield of ≈52% at 483 nm. The origin of bandgap diminution with the increase of shell thickness, or with the utilization of ZnSe shell is unraveled via the first‐principles density functional theory simulations. Simulational evidence on InP‐core densification with the shell coating, along with accompanying changes in chemical and structural properties, is presented. The blue‐emitting InP QD device shows a maximum luminance of 1162 cd m−2 and external quantum efficiency of 1.4%.

Solution-processed colloidal quantum dots for light emission

“…However, the alternative materials to Cd for QLEDs (InP and Cu chalcogenide-based WQLEDs) are significantly poorer in performance, and the EQE of the green and red replacements have to be improved. ( 77) Blue InP and Cu-In-Zn-S QLEDs have additional issues of efficient carrier injection due to their wide bandgap, interface charge transfer between blue QDs and CTLs, and electric field-induced quenching (59,81).…”

“…82 Blue InP and Cu-In-Zn-S QLEDs have additional issues of less efficient carrier injection due to their wide bandgap, interface charge transfer between blue QDs and CTLs, and electric field-induced quenching. 53,85 Research has highlighted the other issues and limitations of QD, usually in the device fabrication phase. Since most quantum dot LED devices use a quaternary structure (Fig.…”

“…82 Blue InP and Cu–In–Zn–S QLEDs have additional issues of less efficient carrier injection due to their wide bandgap, interface charge transfer between blue QDs and CTLs, and electric field-induced quenching. 53,85…”

Predicting Indium Phosphide Quantum Dot Properties from Synthetic Procedures Using Machine Learning

“…(See the full list of input features in Table S1). Using the extended dataset, we hoped to uncover trends of additives based on chemical identity such as fatty amines, zinc salts, and thiol-containing ligands that may play more than one role in the synthesis [32][33][34][35] . For example, since thiols and fatty amines are sometimes used as both coordinating solvents and capping ligands that directly affect the optical properties of QDs, it is more reasonable to separate these features from each other and from other features (solvents and acids) in the dataset with the risk of having a high dimensionality.…”

Charge Transfer in Patterned Bilayer Film of Ag/ZnS Composite by Magnetron Control Sputtering

“…To improve their optical performance, ZnS materials of different microstructures are prepared to regulate the behaviors of carriers, such as ZnS nanostructures of different shapes, components, dopants, and heterojunctions. The charge transfer properties related to the interfaces in the metal-ZnS heterojunctions are vital for applications in various fields, which can be changed by controlling the ZnS thickness [17,18]. The SERS peaks of the probe molecule are sensitive to the charge transfer process, which indicates that SERS is promising in exploring the interface charge transfer process.…”