Scalable Synthesis of High-Quality Core/Shell Quantum Dots With Suppressed Blinking

A facile and reproducible method for scalable synthesis of high-quality core/shell quantum dots (QDs) is a prerequisite to facilitate their versatile applications. Herein, a seed-mediated heat-up approach is developed for the preparation of high-quality core/shell QDs with variable shell composition and continuously tunable shell thickness by selection of conventional salts as the precursors. The method is very simple and highly reproducible and, therefore, can be easily scaled up to get gram-level product. The as-obtained CdSe/CdS and CdSe/ZnCdS core/shell QDs exhibit intriguing optical properties, that is a narrow photoluminescence (PL) emission peak and near-unity PL quantum yield. Importantly, the CdSe/ZnCdS core/shell QDs with a size of 11.4 nm exhibit obviously suppressed blinking behavior, and the fraction of nonblinking QDs (defined by an on-time fraction >= 0.95) can reach as high as 96.0% on the measurement of more than 200 QDs. Moreover, quantum-dot light-emitting diodes (QLEDs) based on CdSe/ZnCdS core/shell QDs show a peak external quantum efficiency of 14.8% and low efficiency roll-off at luminance ranging from 1000 to 25 000 cd center dot m(-2). It is anticipated that the presented work will pave a novel way for the large-scale production of high-quality QDs and further boost their applications in light-emitting diodes, lasing, and biological imaging.

Automated summary

A seed-mediated heat-up approach was developed to synthesize high-quality core/shell quantum dots with variable shell composition and tunable shell thickness. The CdSe/ZnCdS core/shell quantum dots showed suppressed blinking behavior and a high fraction of nonblinking quantum dots. Quantum-dot light-emitting diodes based on CdSe/ZnCdS core/shell quantum dots achieved a peak external quantum efficiency of 14.8% and low efficiency roll-off. This work provides a novel method for large-scale production of high-quality quantum dots and enhances their applications in various fields.