Top-Emission ZnSeTe/ZnSe/ZnS-Based Blue Quantum Dot Light-Emitting Diodes with Enhanced Chroma Efficiency

Abstract

A high-performance quantum dot light-emitting diode (QLED) with heavy metal free (HMF) quantum dots (QDs) is urgently needed for its application in next-generation eco-friendly displays. However, the preparation of high-performance HMF QD materials and the corresponding electroluminescent devices remain challenges at present, especially for blue-emitting devices. In this work, by adjusting the Te/Se ratio of the ZnSeTe core, ZnSeTe/ZnSe/ZnS blue QDs with adjustable energy levels and emission peaks are demonstrated. These QDs are utilized to fabricate top-emitting QLEDs, yielding a peak current efficiency (CE) of 11.8 cd A–1. To make it one step further to meet the requirement of the wide color gamut in displays, the devices’ color coordinates and current efficiency are simultaneously optimized by adjusting their microcavity structure and electrical properties. Finally, the chroma efficiency (current efficiency/CIEy) of the blue devices is optimized to 72, which is 2.2 times that of the control device.

Advancements in semiconductor quantum dots: expanding frontiers in optoelectronics, analytical sensing, biomedicine, and catalysis

“…The fabricated LEDs with ZnSeTe/ZnSe/ZnS CQDs resulted in a peak current efficiency of 11.8 cd A À1 and a chroma efficiency of 72, demonstrating a 2.2 times improvement compared to the control device. 91 Manuela De Franco et al presented a NIR LED based on InAs/ZnSe CQDs. The LEDs achieved a record external quantum efficiency (EQE) of 5.5% at 947 nm and demonstrated an operational lifetime of approximately 32 hours before reaching 50% of their initial luminance.…”

Heavy-metal-free blue-emitting ZnSe(Te) quantum dots: synthesis and light-emitting applications

“…Due to more blue light scattered by SiO 2 nanospheres, the emission peak also blue-shifted from 485 nm to 476 nm, and became narrower, accompanied by an improved angular color stability. In 2023, Feng et al 98 also presented a series of top-emitting blue ZnSeTe QLEDs with emission peaks at 462, 477, and 491 nm, respectively by using ZnSe:xTe/ZnSe/ZnS QDs with a PLQY of about 50% as emitters. These QDs had PL peaks of 455, 460, and 470 nm, obtained by injecting different Te/Se molar ratios.…”

Near‐Unity Quantum Yield ZnSeTe Quantum Dots Enabled by Controlling Shell Growth for Efficient Deep‐Blue Light‐Emitting Diodes

“…Environmentally friendly ZnSeTe QDs show tunable emission wavelengths by adjusting the Te/Se ratio, endowing them with promising blue light emitters. [11][12][13][14][15][16][17][18][19] Since Jang et. al.…”