SBIR Phase I: Silicon Quantum-dot Phosphors for LED General Illumination

这个小型企业创新研究第一阶段项目旨在利用荧光纳米颗粒或硅制成的量子点来大大提高白光发光二极管（led）的光输出。现代白光LED最有效和最经济的设计是基于蓝色LED芯片，该芯片可以激发发出黄色的稀土荧光粉。这种蓝色和黄色色调的特殊混合产生一种冷色和蓝白色的光，这种光不能忠实地呈现被照亮物体的某些颜色，特别是在红色色调的情况下。提出的解决方案将红色增强硅量子点（SiQDs）放置在这些白光led的光束路径中；通过吸收部分蓝光输出并重新发射红光，siqd补充了缺失的红色光谱，从而提高了整体显色性能。到目前为止，该公司已经建立了可扩展生产明亮发光siqd的基准方法。该一期项目将使公司能够提高siqd的性能，并建立其长期性能稳定性。该项目的更广泛影响/商业潜力是开发最终可以取代目前稀土衍生荧光粉的siqd。中国实际上垄断了全球稀土供应，并对开采和出口实施严格限制，以利用其地位。因此，用于封装白光LED的稀土荧光粉的成本将飙升，因为供应减少和市场对额外稀土荧光粉（如铕掺杂氮化物或硫化物）的需求不断增加，以产生优质LED产品的红色。因此，迫切需要一种储量丰富、成本低廉的替代荧光粉材料。半导体量子点由于其宽波长可调性和高光致发光量子产率被认为是一种很有前途的解决方案。由于硅的惰性性质和丰富度，与现有的重金属镉-硫系量子点材料（如CdSe量子点）相比，siqd可以提供无毒、高稳定性和低成本的解决方案。该项目将作为开发一系列产品的第一步，这些产品允许通过siqd荧光粉产生所有可见光波长，从而使白光led不需要稀土和镉基荧光粉。这将使LED照明更美观，更实惠，更环保。

This Small Business Innovation Research Phase I project seeks to greatly improve the light output of white-light light-emitting diodes (LEDs) using fluorescent nanoparticles or quantum dots (QDs) made from silicon. The most efficient and economical design for a contemporary white LED is based on a blue LED chip which excites a yellow-emitting rare-earth phosphor. This particular mix of blue and yellow hues produces a cool and bluish-white light which cannot faithfully render some colors in illuminated objects, especially in the case of red tones. The proposed solution places red-color-enhancing silicon-QDs (SiQDs) in the beam-path of these white LEDs; by absorbing some of the blue light output and re-emitting red light, the SiQDs complement the absent red spectrum, and thus improve the overall color rendering performance. The company has thus far established baseline methodologies for the scalable production of brightly luminescing SiQDs. This Phase I project will enable the company to improve the performance of said SiQDs, and also establish their long-term performance stability.The broader impact/commercial potential of this project is to develop SiQDs that can ultimately replace current rare-earth-derived phosphors. China has a virtual monopoly over global rare-earth supply, and is enacting draconian restrictions on extraction and exportation to capitalize on its position. The cost of rare-earth phosphors used in packaged white-light LEDs is thus set to soar because of the dwindling supply and increasing market demand for additional rare-earth phosphors (such as europium-doped nitrides or sulfides) to generate reds for premium LED offerings. Hence, an earth-abundant and cost-effective alternative phosphor material is desperately needed. Semiconductor QDs are considered a promising solution due to their wide-range wavelength-tunability and high photoluminescence quantum yield. Because of the inert nature and the abundance of silicon, SiQDs can provide a non-toxic, high-stability, and lower cost solution, in comparison with established heavy-metal cadmium-chalcogenide QD materials (such as CdSe QDs). The project will serve as the first step in the development of a repertoire of products which permit the creation of all visible light wavelengths via SiQD-phosphors, allowing white-light LEDs to be free from the need for rare-earth- and cadmium-based phosphors. This will in turn make LED lighting more aesthetically attractive, affordable, and environmentally friendly.