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摘要: 量子点材料兼具极高的色纯度、发光颜色可调以及的荧光量子产率高等特点,已成为显示领域中的明星材料,在提升显示器件的色域方面具有巨大潜力。基于量子点材料的液晶显示背光技术是目前量子点材料在显示器件中的主流应用方向,引起了学术界和工业界的广泛关注。本文将综述量子点液晶显示背光技术的研究进展,主要包括量子点材料的选择、背光结构的应用以及材料复合与封装技术的发展现状,重点介绍了目前产业界广泛关注的量子点光学膜技术,特别是国内自主知识产权的低成本钙钛矿量子点光学膜技术,由于其具备广色域(124% NTSC)、易加工、低成本等特点,已成为具有成长潜力的技术路线。Abstract: Quantum dots are rising as suitable candidates in the field of display application due to their extremely high color purity, tunable emission spectra and high photoluminescence efficiency, especially for their contribution to the expanded color gamut in display technology. Motivated by the commercialization in the market, quantum dots based backlights have drawn great deal of attentions from both the scientific and industrial circles. In this paper, the research progress of quantum dot liquid crystal display backlight technology is reviewed, including the selection of quantum dots materials, the application of backlight structure and the development of composite materials and encapsulation technology. In addition, this paper also introduces the low-cost perovskite quantum dot optical film technology, which is widely concerned by industrial circle, especially the low-cost perovskite quantum dot optical film technology with independent intellectual property rights. This technology has the advantages of wide color gamut(124% NTSC), easy processing, and low cost with a great development potential.
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Key words:
- quantum dot /
- backlight technology /
- wide color gamut /
- display /
- perovskite /
- optical film
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图 2 量子点背光结构示意图:(a)“芯片封装型”结构,量子点发光材料封装在蓝光LED贴片上; (b) “侧管封装型”结构,量子点与基质形成的复合材料置于蓝光LED与导光板的侧边; (c) “光学膜集成型”结构,量子点与基质形成的量子点光学膜置于导光板的正上方[26]
Figure 2. Schematic of quantum dots based backlight: (a)"On-chip" structure, in which the quantum dot light emitting material is encapsulated on the blue LED chip. (b)"On-edge" structure, where the quantum dot based composite material is placed on the side between the blue LED and the light guide plate. (c)"On-surface" structure, where the quantum dots based optical film is directly placed above the light guide plate[26]
图 3 (a)CdSe/ZnS量子点与NaCl无机盐晶体形成的复合发光材料[39];(b)CdSe/CdS/ZnS量子点与二氧化硅通过溶胶-凝胶缩合反应形成的复合发光玻璃[42];(c)复合发光玻璃与有机硅胶树脂基复合发光材料的热稳定性对比[42]
Figure 3. (a)Composite formed by embedding CdSe/ZnS quantum dots in NaCl crystals[39]. (b)Inorganic silica-based glass formed by embedding CdSe/CdS/ZnS quantum dots in silica monolith[42]. (c)Thermal stability of inorganic silica-based glass and organic silicone resin-based composite material[42]
图 4 (a)InP/ZnS量子点与PMMA基质复合得到的大面积量子点光学膜[48]; (b)CdSe/ZnS量子点与PVA基质复合得到的透明量子点光学膜[50]; (c)CdSe/ZnS量子点与氧化聚乙烯基质形成的复合材料结构示意图[53]; (d)量子点光学膜两侧的阻隔膜结构示意图[60]
Figure 4. (a)Quantum dot based optical film with large area [48]. (b)Quantum dots based optical films with high transparency[50]. (c)Quantum dots based optical films with stable structure[53]. (d)Quantum dots based optical films with barriers[60]
图 5 (a)引发量子点表面的可聚合单体发生原位聚合反应,制备所需的聚合物基量子点复合材料[74];(b)采用量子点在聚合物基质中原位形核与生长的方式来制备聚合物基量子点复合薄膜材料[76]
Figure 5. (a)Quantum dots based composite fabricated by in-situ polymerization of the surface monomers[74]; (b)Quantum dots based composite film fabricated by in situ nucleation and growth of the quantum dot in the polymer matrix[76]
图 6 (a)“原位制备技术”制备的大面积钙钛矿量子点光学膜; (b)基于钙钛矿量子点光学膜的背光源和显示器样机在CIE色度图中的色域三角形; (c)集成有钙钛矿量子点光学膜的显示器样机与苹果笔记本显示器的显示效果对比
Figure 6. (a)Perovskite quantum dots based optical film prepared by "in-situ fabrication technique". (b)The color triangle of obtained backlight and LCD prototype in CIE 1931 diagram. (c)Comparison of a colorful picture display on the LCD prototype and Apple MacBook Air
表 1 量子点光学膜的系列优化方法及其应用效果
Table 1. A series of optimization methods for quantum dot based optical films and corresponding effects
大面积 稳定性好 制备工艺简单 透明性高 发光效率高 基质选择 √ × × × √ 界面相容性 × × × √ √ 聚合物结构 × √ × × √ 阻隔膜技术 × √ × × √ 商品化技术 √ √ × × √ 原位聚合 × × × √ × 原位生长 × × √ × × 原位制备技术 √ ? √ √ √ -
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