Continuously Graded Quantum Dots: Synthesis, Applications in Quantum Dot Light-Emitting Diodes, and Perspectives

Abstract

Colloidal quantum dot (QD) light-emitting diodes (QLEDs) hold the promise of next-generation displays and illumination owing to their excellent color saturation, high efficiency, and solution processability. For achieving high-performance lightemitting diodes (LEDs), engineering the fine compositions and structures of QDs is of paramount importance and attracts tremendous research interest. The recently developed continuously graded QDs (cg-QDs) with gradually altered nanocompositions and electronic band structures present the most advanced example in this area. In this Perspective, we summarize the current progress in LEDs based on cg-QDs, mainly concentrating on their synthesis and advantages in addressing the great challenges in QLEDs, like efficiency roll-off at high current densities, short operation lifetimes at high brightness, and low brightness near the voltage around the bandgap. In addition, we propose accessible approaches exploiting the cutting-edge mechanisms and techniques to further optimize and improve the performance of QLEDs.

Biogenic Sulfur-Based Chalcogenide Nanocrystals: Methods of Fabrication, Mechanistic Aspects, and Bio-Applications

“…Among the biogenic S-NPs described here, QDs constitute the predominant class used for specific bio-applications. Besides being applied in optoelectronic devices, sensing, and photocatalysis [223][224][225][226][227], these NPs are gaining interest in the biomedical field [15,29,38].…”

Fast-response, high-stability, and high-efficiency full-color quantum dot light-emitting diodes with charge storage layer

“…Colloidal quantum dot light-emitting diodes (QLEDs) have attracted considerable attention in the display and lighting fields due to their unique advantages, such as high color purity, tunable emission wavelength covering the entire visible region as well as the low manufacturing cost [1-9]. To the present, QLEDs have achieved enormous progress in device efficiency by improving quantum yields (QYs) of quantum dots (QDs), balancing device charge carriers, and restricting carrier quenching [10][11][12][13][14][15][16][17][18]. According to the recent results, the efficiency of QLEDs has been comparable to that of organic light emitting diodes (OLEDs) [3, [19][20][21].…”

Observation and Suppression of Stacking Interface States in Sandwich-Structured Quantum Dot Light-Emitting Diodes

“…The sandwich structure has been the most prevailing device architecture used in large-area optoelectronic applications such as organic light-emitting diodes, , quantum dot (QD) light-emitting diodes (QLEDs), − and solar cells. − With the development of colloidal QDs with excellent luminescence efficiency, QLEDs fabricated with solution-based spin-coating and inkjet printing processes have shown great promise in realizing large-area flexible displays at low cost. − Although much effort has been invested in enhancing the emission efficiency and stability of QDs, − ,− efficient carrier transport and injection through the functional layers are also crucial to the overall device performances. ,− In particular, interface states inevitably form at the junctions when heterogeneous functional layers are stacked on one another via solution-based processes, ,− leading to adverse effects on the device performances. Optimizing the carrier transport layers, as well as their interfaces, is therefore key for enhancing the power efficiency (PE), reliability, and working lifetime of QLEDs. ,,− …”