白光发光二极管（LED）具有节能、寿命长、体积小、发光效率高等优点，因此被誉为下一代照明光源。目前，LED荧光粉仍然主要依赖稀土荧光粉，但是它具有价格昂贵、合成工艺复杂及荧光发射峰窄等缺点。目前，半导体量子点由于其具有吸收覆盖范围广、荧光可调、量子产率高等优异的光学特性，已经被广泛用于白光LED。但是，半导体量子点往往含有镉、铅等毒性元素且制作成本高，限制了其实际应用。近年来，碳量子点作为一种新型的荧光纳米材料，具有原料来源广泛、成本低廉、环境友好、发射波长可调、荧光稳定性好、制备方法简单等优点。因此，它可以作为稀土荧光粉和半导体量子点的良好替代物被应用于白光发光二极管（LED）领域，并已经引起了研究者们的广泛关注。目前，碳量子点在白光LED领域的应用尚处于起步阶段，仍然存在色温较高、显色指数和发光效率较低等问题，限制了碳量子点在白光LED领域的广泛应用。针对以上问题，本论文主要研究内容包括：采用溶剂热方法成功合成了一种高量子产率的红色荧光碳量子并应用于高显色指数的暖白光LED的构建；通过微波溶剂热方法合成了具有色温可调的白光碳量子点，成功制备了高性能的冷、纯和暖白光LED；通过水热合成法制备了具有固体荧光性质的蓝、绿、红光碳量子点，应用于高性能的暖白光LED的构建。具体工作如下： 1. 以1, 3-二羟基萘为前驱物，高碘酸钾为氧化剂，通过水热方法成功合成了红光碳量子点，荧光量子产率高达53%，超过了以往报道的红光碳量子点。将红光碳量子点与我们实验室的蓝、绿光碳量子点结合，通过近紫外LED芯片激发，首次制备了基于三基色碳量子点荧光粉的暖白光LED，显色指数高达97，超过了基于半导体量子点的白光LED。通过改变器件结构，将发光效率提高到了31.3 lm/W。本工作为探索低成本、环境友好的碳量子点的暖白光LED开辟了道路。 2. 以柠檬酸和尿素为前驱物在甲酰胺溶液中微波溶剂热反应，通过控制反应条件，成功合成了三种不同色温的白光碳量子点，分别可以发出冷白光、纯白光和暖白光，荧光量子产率最高可达26.7%，为目前最高值。将冷白光、纯白光和暖白光碳量子点荧光粉分别与近紫外LED芯片结合，成功制备了冷白光LED、纯白光LED和暖白光LED。其中，显色指数高达95.6，发光效率可达22.3 lm/W。本工作制备的高效白光碳量子点有望作为商业化白色荧光粉广泛应用于白光LED领域。 3. 将对苯二乙腈分别与邻苯二甲醛和对苯二甲醛水热反应，并通过调控反应条件，可以得到蓝、绿、红色固体荧光碳量子点，量子产率高达46%，为目前最高值，并且产量可以达到克量级。将蓝、绿、红色固体荧光碳量子点与近紫外LED芯片结合，首次实现了基于三基色固体荧光碳量子点的暖白光LED的制备，显色指数高达96.6，发光效率为48.7 lm/W，甚至可以与商业化白光LED相媲美。通过调整固体荧光碳量子点之间的比例，也成功制备了纯白光LED，色坐标为（0.334, 0.332），非常接近标准白光LED的色坐标（0.33, 0.33）。本工作为制备可量产的高效固体荧光碳量子点提供了一种新方法，并且有望广泛应用于商业化白光LED领域。

White light-emitting diodes (WLEDs) have been hailed as the next-generation lighting source due to energy-saving, long lifetime, small volume and high luminous efficiency. Currently used LED phosphors are based on rare-earth phosphors. However, they exhibit high cost, complex synthesis process and narrow emission band. Colloidal semiconductor quantum dots (QDs) have been widely used for the development of WLEDs due to the unique optical properties such as broad absorption spectra, color tunability as well as high quantum yield (QY). However, the severe toxicity and high cost have greatly limited the use of heavy metal Cd2+/Pb2+-based QDs for wide practical applications. In the past few years, carbon quantum dots (CQDs) have attracted tremendous attention as promising alternatives for rare earth ion and semiconductor QDs in WLEDs, owing to their outstanding characteristics such as low cost, low cytotoxicity, tunable photoluminescence, photostability, as well as simple preparation method. Although some efforts have been made to realize the great potential applications of CQDs in WLEDs, the WLEDs still have defects such as high correlated color temperature, low color index and luminous efficiency, which severely hinder their development in WLEDs field. To target with these problems, in this dissertation, highly efficient red emissive CQDs was synthesized by solvothermal method, and used for warm WLEDs with a high CRI. Tunable white fluorescent CQDs were synthesized by solvothermal method, and realized high-performance cool, pure and warm WLEDs. The large-scale synthesis of highly efficient bule/green/red solid-state fluorescent CQDs was realized by hydrothermal method, and used for high-performance WLEDs. The main works are as follows: We demonstrated the fabrication of highly efficient red emissive CQDs with a quantum yield (QY) up to 53% by solvothermal reaction of 1, 3-dihydroxynaphthalene and KIO4, which is the highest value recorded for red fluorescent CQDs. Using such red emissive CQDs as red emitting phosphor, in combination with blue emissive CQDs and green emissive CQD phosphors, we have for the first time realized a UV-pumped CQD phosphors-based warm WLEDs with a high CRI of 97, which is higher than the semiconductor QDs-based WLEDs reported previously. After optimizing device structure, the warm WLED achieved a high luminous efficiency of 31.3 lm W?1. This work opens up new avenues for the exploration of low cost, environment-friendly and high performance CQDs phosphors-based warm WLEDs. Three kinds of white fluorescent CQDs with a QY up to 26.7% were prepared by solvothermal reaction of citric acid and urea by reasonable control of reactive condition in formamide. These white fluorescent CQDs emitted cool, pure and warm white fluorescence under UV light illumination, respectively. Using these white fluorescent CQDs as phosphors, in combination with UV-LED chip, we successfully prepared cool, pure and warm WLEDs. In addition, these WLEDs featured a high CRI of 95.6, and the luminous efficiency was as high as 22.3 lm W?1. These high efficient white fluorescent CQDs as a phosphor are expected to be used in commercial white LEDs field. We demonstrated the fabrication of gram-scale solid-state fluorescent CQDs from blue to red with QY of 46% via hydrothermal reaction of phthaldehyde and p-phenylenediacetonitrile by control of reaction condition. Using blue, green and red solid-state fluorescent CQDs as phosphors, in combination with UV-LED chip, we have for the first time realized UV-pumped solid-state fluorescent CQDs-based warm WLEDs with a high CRI of 96.6. The luminous efficiency of warm WLEDs was as high as 48.7 lm W?1, which was even comparable to commercialized WLEDs. By adjust the ratios of CQDs phosphors, we also fabricated pure WLEDs with Commission on Illumination coordinate (0.333, 0.333), which was close to pure white light (0.33, 0.33). This work provides a new method for the preparation of high efficient large-scales solid fluorescence CQDs, which is expected to be widely used in commercial white LEDs field.