胶体量子阱发光二极管的研究进展

胶体量子阱(CQW)由于具有高色纯度、高光致发光量子效率、光色可调等优异的光电性能，近年来成为一种新型的光电材料，广泛用于制备发光二极管、激光、探测器、太阳能电池等半导体器件。其中，基于CQW的发光二极管(CQW-LED)因为具备极窄的光谱、极佳的色纯度、高效率、可溶液加工、可柔性化等优点，在显示和照明等领域展现出重要应用前景，受到学术界和工业界的广泛重视而成为研究热点。本文首先介绍了CQW-LED中的一些基本概念，包括CQW材料特性、LED器件结构、发光机理等；然后从CQW材料种类的角度出发，阐述了基于单核型、核/冠型、核/壳型、复杂异质结型、以及杂质掺杂型CQW-LED近年来的研究进展，并结合我们研究团队最近的工作详细的介绍了实现高性能CQW-LED的方法，包括对材料选取、设计策略、器件结构、器件性能、工作机理以及发光过程的分析；接着，介绍了CQW-LED的集成应用；最后探讨了CQW-LED目前面临的挑战及其未来的发展机遇。

Progress in the Development of Colloidal Quantum Well Light-Emitting Diodes

In recent years, colloidal quantum wells (CQWs), also known as semiconductor nanoplatelets, have become the new kind of promising optoelectronic material because of their excellent optoelectronic properties, such as high color purity, high photoluminescence quantum efficiency, and adjustable color emissions. As a significant application of CQWs, light-emitting diodes based on CQWs (or CQW-LEDs) possess a number of advantages, such as an extremely narrow spectrum, excellent color purity, high efficiency, solution-processed fabrication, and good compatibility with flexible electronics. CQW-LEDs demonstrate an important application prospect in the fields of next-generation display and solid-state lighting, and therefore, attract significant attention from academic and industrial settings. In this review, some basic concepts of CQW-LEDs are first introduced (e.g., the design of CQW materials, employment of device structures, and understanding of emission mechanisms), which are expected to help with understanding this new type of LEDs. Thereafter, from the perspective of CQW emitting material types, the recent research progress in the development of CQW-LEDs based on core-only CQWs, core/crown CQWs, core/shell CQWs, complex-heterojunction-based CQWs, and impurity-doped CQWs is presented. The properties of various CQWs are also compared. In this section, by combining the recent work from our research group, the design strategies of high-performance CQW-LEDs are discussed in detail, including the analyses of material selection, device structure, working mechanism, and luminescence process. In the next section, the integrated applications of CQW-LEDs are illustrated, such as their use in LiFi-type communication, furthermore, their preparation as flexible optoelectronic materials is also reported. Finally, the present challenges (e.g., low efficiencies, short lifetimes, sub-optimal device engineering, and a narrow emission color region) and future development opportunities (e.g., flexible displays, flexible lighting, and CQW-LEDs with low-cost printing fabrication processes) of CQW-LEDs are discussed. Although the performance of CQW-LEDs still lags behind other kinds of state-of-the-art soft-material-based LEDs (e.g., organic LEDs, colloidal quantum dot LEDs, and perovskite LEDs), it has been gradually enhanced in the last eight years. Upon overcoming the current challenges, the prospect for the mass production of CQW-LEDs will be undoubtedly feasible. Thus, this review is not only an important reference that discusses the evolution of CQW-LEDs, it also provides insightful ideas for the development of materials for other optoelectronic applications (e.g., solar cells, lasers, photodetectors, sensors, X-ray imaging, and light communication).