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

非技术描述：在美国，家庭和商业建筑的照明占美国总电能使用量的6%，占总电能支出的15%，相当于每年500亿美元。通过用白色发光二极管（LED）代替当前的白炽灯和荧光灯照明，存在显著的机会来降低该成本。然而，颜色质量和效率必须进一步提高。这些基于LED的灯泡通过使用一种称为磷光体的发光粉末产生白色光，该粉末涂覆在近紫外（UV）或蓝色发光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，目前只有少数可行的荧光粉可用于此应用。因此，谨慎地发现新的磷光体系统以完全实现向新的高效照明的转换。研究人员正在通过开发计算和数据驱动的方法来预测磷光体的特性来应对这一挑战。这种方法允许直接发现具有增强的光学响应的新磷光体。该补助金还支持广泛的科学教育，包括为高中和本科生提供众多研究机会。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磷光体以及这种节能技术的重要性。这项工作支持的研究生接受培训，以寻求光电子行业的机会，并在材料科学发挥关键作用的技术领域。最后，本研究的计算产品通过开源平台传播，因此所有研究人员都能从科学发展中受益。 技术规格：用节能的磷光体转换发光二极管取代传统灯泡是减少电力消耗的最简单方法之一。这一目标需要发现新的荧光粉系统，将几乎单色的LED光转换为宽光谱的白色光，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（基质）。取决于主体：活化剂组合，获得整个可见光谱的颜色。驱动这项研究的中心假设是，磷光体的量子效率和热猝灭电阻与活化剂离子的局部配位环境有关。这项研究采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特性进行建模，并通过材料合成和表征来确认预测，从而产生一个反馈回路，使我们的研究结果随着每次发现而得到改进。该奖项反映了NSF的法定使命，通过使用基金会的知识价值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.