Rational Design and Synthesis of Highly Luminescent Multinary Cu‐In‐Zn‐S Semiconductor Nanocrystals with Tailored Nanostructures

Abstract

Multinary copper chalcogenide semiconductor nanocrystals (NCs) have achieved increased attention due to their lessened toxicity and compositional versatility as well as their outstanding optical properties and optoelectronic applications in light‐emitting diodes (LEDs) and solar cells. Herein, the synthesis of highly luminescent multinary Cu‐In‐Zn‐S semiconductor NCs with tailored nanostructures, which exhibit the best absolute photoluminescence quantum yield of 90%, is presented. The tailored nanostructures are realized through the variation of the dosage and injection speed of Zn precursors, which determine the balance between Zn2+ cation diffusion and ZnS shelling reaction. The depth profile measured using X‐ray photoelectron spectroscopy reveals the gradient distribution of Zn elements from core to surface in the samples synthesized using higher feeding amounts of Zn precursors in a one‐pot method, which favors the formation of a soft core/shell structure. Time‐resolved spectroscopic studies confirm that the inward diffusion of Zn2+ and overcoating of a ZnS shell could reduce the number of intrinsic internal or surface defects, finally inducing a near‐unity radiative decay of excitons in single recombination pathway. As a demonstration, the highly luminescent multinary Cu‐In‐Zn‐S semiconductor NCs are incorporated into LEDs and a white light‐emitting diode is accessed through a two‐component strategy.

Semiconductor Nanocrystals Emitting in the Second Near‐Infrared Window: Optical Properties and Application in Biomedical Imaging

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Synthesis and structure design of I–III–VI quantum dots for white light-emitting diodes

“…However, in most cases, the shell coating and alloying processes occur simultaneously, forming a core/gradient alloy/shell structure. 77,78 A delicate balance between several processes determines the outcome of shelling reactions on QDs. It is not easy to distinguish between a core-shell structure and an alloyed structure after the shelling process.…”

Multinary copper-based chalcogenide nanocrystal systems from the perspective of device applications

“… 174 Recently, Liu et al have reported a new WLED composed of highly luminescent Cu–In–Zn–S nanocrystals showing a nearly 90% photoluminescence quantum yield. 175 …”