image: Key challenges in the development of InP-based QDs and ZnSe-based QDs.
Credit: OES
A new publication from Opto-Electronic Sciences; DOI 10.29026/oes.2025.240028 , discusses eco-friendly quantum-dot light-emitting diode display technologies.
Colloidal quantum dots (QDs) exhibit exceptional properties of narrow-band emission, tunable luminescent wavelength, high luminous efficiency, and remarkable material stability across the visible and infrared spectra, making them highly valuable in diverse applications like imaging, solar collection, displays, communications, and medical. Quantum dot light-emitting diodes (QLEDs) are paving the way for them to emerge as the leading technology in next-generation solid-state lighting and flat panel display. Additionally, the stringent regulations on heavy metal elements in the European Union have posed significant hurdles to the commercialization prospects of cadmium-based QDs.
Indium phosphide (InP) QDs, as a substitute for cadmium selenide (CdSe) QDs, have been extensively studied for the development of cadmium-free QLEDs. However, the utilization of InP for blue QLEDs remains challenging due to its narrow intrinsic bandgap of 1.35 eV. Although blue light emission can be achieved by controlling the particle size within 1-2 nm, this poses immense difficulties in the thermal injection synthesis process. In particular, by alloying zinc telluride (ZnTe) with a narrower bandgap of 2.25 eV and zinc selenide (ZnSe) with a wider bandgap of 2.70 eV, the resulting ZnSeTe QDs are considered the most promising candidates for cadmium-free blue QDs.
By combining the advantages of InP and ZnSe quantum dots while overcoming their limitations, it is expected to open up new avenues for the development of cadmium free full-color QLED devices, demonstrating the broad prospects of future display technology.
This paper undertakes a specific review of all technological breakthroughs that aim to tackle the above challenges associated with cadmium-free QLED displays. It begins by reviewing the evolution, architecture, and operational characteristics of eco-friendly QLEDs, highlighting the photoelectric properties of QDs, carrier transport layer stability, and device lifetime. Subsequently, it focuses our attention not only on the latest insights into device degradation mechanisms, but also on the remarkable technological progress in color patterning techniques. To conclude, this paper provides a synthesis of the promising prospects, current challenges, potential solutions, and emerging research trends for QLED displays.
Quantum dots have attracted widespread attention due to their unique luminescent properties and vibrant color range. Exploring the degradation mechanism of cadmium-free devices and developing high-performance, long-lasting cadmium-free QLEDs have laid the foundation for the industrialization of environmentally friendly QLED pixel graphic technology. This further expands the application of quantum dots into fields such as light therapy, biosensing, lasers, and visual optical communication.
Keywords: quantum dots / eco-friendly / light-emitting diodes / degradation mechanisms / displays
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The institute of Applied Physics and Materials Engineering at the University of Macau focuses on the fundamental scientific issues and device development applications of semiconductor materials and nanomaterials, particularly in the development of next-generation photovoltaic cells and light sources. Among them, the research team led by Associate Professors Wang Shuangpeng and Wu Jiawei primarily engages in research on photoelectric materials and devices related to surfaces and interfaces, covering device physics of quantum dot light-emitting devices, physicochemical properties of halide perovskite materials and their applications in photodetection, surface functionalization of nanoluminescent materials. The team has published a total of 190 papers with a cumulative citation count of 5,800. Research Group Homepage: https://iapme.um.edu.mo
Dr. Yin Zhen is currently a lecturer at the School of Digital Media, Shenzhen Polytechnic University. His primary research interests lie in the fields of photoelectric sensing and detection technology, surface-enhanced Raman spectroscopy, plasmonic photonics, photoelectric materials and devices. He has hosted and participated in over 10 projects, including General and Youth Programs funded by the National Natural Science Foundation of China, projects funded by the Natural Science Foundation of Guangdong Province, and key basic research projects in Shenzhen. To date, he has published more than 27 papers in total.
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Opto-Electronic Science (OES) is a peer-reviewed, open access, interdisciplinary and international journal published by The Institute of Optics and Electronics, Chinese Academy of Sciences as a sister journal of Opto-Electronic Advances (OEA, IF=15.3). OES is dedicated to providing a professional platform to promote academic exchange and accelerate innovation. OES publishes articles, reviews, and letters of the fundamental breakthroughs in basic science of optics and optoelectronics.
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Gao PL, Li C, Zhou H et al. Eco-friendly quantum-dot light-emitting diode display technologies: prospects and challenges. Opto-Electron Sci 5, 240028 (2025). doi: 10.29026/oes.2025.240028
Journal
Opto-Electronic Science