Collaborative Research: Designing New Phosphors using Computational and Experimental Co-discovery

非技术描述：美国住宅和商业建筑的照明占美国总用电量的6%，占总用电量的15%，相当于每年500亿美元。用白光发光二极管(LED)取代目前的白炽灯和荧光灯，是降低这一成本的绝佳机会。但是，色彩的质量和效率还有待进一步提高。这些基于LED的灯泡通过使用一种名为荧光粉的发光粉末来产生白光，这种粉末被涂在近紫外线(UV)或蓝光LED芯片的顶部。荧光粉是这些设备中的关键组件，因为它对这些灯泡的整体效率和颜色至关重要；不幸的是，目前只有少数几个可行的荧光粉可用于这种应用。因此，谨慎地发现新的荧光粉系统，以充分实现向新的高效照明的转换。研究人员正在开发计算和数据驱动的方法来预测荧光粉的性质，以应对这一挑战。这种方法允许定向发现具有增强的光学响应的新的荧光粉。这笔赠款还支持广泛的科学教育，包括为高中生和本科生提供大量的研究机会。这些学生大多来自代表性不足的群体，他们正在学习如何合成和表征荧光粉，以及这种节能技术的重要性。由这项工作支持的研究生接受了在光电子行业以及材料科学发挥关键作用的技术部门寻求机会的培训。最后，这项研究的计算产品通过开源平台传播，因此所有研究人员都从科学发展中受益。技术细节：用节能的荧光粉转换发光二极管取代传统灯泡是降低电力消耗的最容易的方法之一。这一目标需要发现新的荧光粉系统，将几乎单色的LED光转换为广谱白光，以充分利用这项技术。本项目研究的荧光粉是基于含有少量激活剂(稀土元素)的宽带隙材料(主体)。根据主机：激活剂的组合，可获得可见光光谱上的颜色。推动这项研究的中心假设是，荧光粉的量子效率和抗热猝灭能力与激活剂离子的局部配位环境有关。这项研究利用先进的第一性原理计算、使用X射线和中子散射的局部结构分析以及数据科学来建立对这种关系的定量理解。使用计算工具对这些性质进行建模，并通过材料合成和表征来确认预测，会产生一个反馈回路，在这个回路中，我们的研究结果随着每一次发现而得到改进。其结果是一系列设计规则，将导致发现具有优异光学性能的新荧光粉。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL DESCRIPTION: Lighting home and commercial buildings in the US account for 6% of the total US electrical energy use and 15% of the total electrical energy expenditure, which translates to $50 billion per year. There is an outstanding opportunity to reduce this cost by replacing current incandescent and fluorescent lighting with white light emitting diodes (LEDs). However, the color quality and efficiency must be improved further. These LED-based light bulbs produce white light by using a luminescent powder called a phosphor, coating on top of a near-ultraviolet (UV) or blue-emitting LED chip. The phosphor is a key component in these devices because it is critical for the overall efficiency and color of these bulbs; unfortunately, there are only a few viable phosphors available for this application today. Therefore, it is prudent to discover new phosphor systems to fully realize the conversion to new efficient lighting. The researchers are addressing this challenge by developing computational and data-driven methods to predict the properties of phosphors. This approach allows the directed discovery of new phosphors with enhanced optical response. This grant also supports extensive scientific education including sponsoring numerous research opportunities for high school and undergraduate students. These students, mostly from underrepresented groups, are learning how to synthesize and characterize phosphors as well as the importance of this energy-efficient technology. The graduate students supported by this work are trained to pursue opportunities in the optoelectronics industry and also across the technology sector where materials science play a crucial role. Finally, the computational products of this research are disseminated through open-source platforms, so all researchers benefit from the scientific developments. TECHNICAL DETAILS: Replacing a traditional light bulb with an energy-efficient, phosphor converted-light emitting diode is one of the easiest ways to decrease electricity consumption. This goal requires the discovery of new phosphor systems, which convert the nearly monochromatic LED light into a broad spectrum white light, to fully make use of this technology. The phosphors investigated in this project are based on wide band gap materials (hosts) that contain a small amount of activator (rare-earth element). Depending on the host:activator combination, colors across the visible spectrum are obtained. The central hypothesis driving this research is that the quantum efficiency and thermal quenching resistance of a phosphor are related to the local coordination environment of the activator ion. This research employs advanced first-principles calculations, local structure analysis using X-ray and neutron scattering, and data science to establish a quantitative understanding of this relationship. Modeling these properties using computational tools and confirming the predictions through materials synthesis and characterization produces a feedback loop where our research results are improved with each discovery. The outcome is a series of design rules that will lead to the discovery of new phosphors with superior optical properties.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.