Collaborative Research: Chalcogenide Perovskite Light Emitting Diodes to Fill the Green Gap

固态照明在大幅减少能源消耗方面起着核心作用。当前led的效率从蓝光区域的~ 80%急剧下降到绿色区域的~ 15%。这种缺乏合适的半导体绿色光源被称为“绿隙”问题。这项研究旨在通过基于一种全新的半导体材料——硫系钙钛矿——开发绿色led来解决这个问题。这项工作是打开基于硫系钙钛矿的半导体器件研究新前沿的关键一步，对传感、能量收集、信息处理和存储等应用具有深远的影响。在这些材料中使用地球丰富的元素可以减少我们国家对稀土材料的依赖。通过与当地工业界的合作，这项拟议的工作还将为高级实验课程开发样品和仪器，这不仅将影响美国和全球的STEM教育，还将影响纽约西部的当地经济。研究活动涉及机器学习、第一性原理计算、材料合成、设备制造和表征，将通过有针对性地从代表性不足的群体中招募学生，为多元化的学生群体提供重要的跨学科培训。该提案旨在展示第一个基于硫系钙钛矿的发光二极管，其长期目标是弥合LED技术的绿色差距。这将涉及一个迭代过程，其中理论预测将指导材料合成，原子级结构、光学和载流子输运特性将为理论模型以及设备设计和制造提供信息。这项工作的想法是基于主要研究人员最近对具有可调带隙和有前途的半导体性质的硫系钙钛矿材料的预测和实现。具体项目目标为：i)开发一种与器件制造兼容的低温硫系钙钛矿薄膜加工技术，并生长出高质量的具有强绿光和琥珀光发射的SrHfS3和SrZrS3薄膜。ii)通过协调第一性原理计算和原子尺度结构、光学和载流子输运特性的实验来控制器件性能。iii)设计、制造和评估n型和p型掺杂SrHfS3和SrZrS3薄膜的绿色和琥珀色led。一种结合微转移打印的创新器件制造技术允许不同材料形成具有极其干净界面的高质量p-i-n型LED结构，而不受其生长条件的限制。该奖项反映了美国国家科学基金会的法定使命，并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。

Solid-state lighting plays a central role in substantially reducing the amount of energy consumption. The efficiency of current LEDs drastically decreases from ∼80% in the blue-light regions to ∼15% in the green region. This lack of a suitable semiconductor green light source is known as the “green gap” problem. This research aims to address this problem by developing green LEDs based on an entirely new family of semiconductor materials called chalcogenide perovskite. The proposed work is a critical step towards opening a new frontier in semiconductor device research based on chalcogenide perovskites, with far reaching impacts on applications such as sensing, energy harvesting, information processing, and storage. The use of earth-abundant elements in these materials can reduce our nation’s reliance on rare-earth materials. Through collaboration with local industry, the proposed work will also develop samples and instrumentation for advanced laboratory courses, which will not only impact STEM education in the US and worldwide, but also the local economy in Western New York. The research activities involving machine learning, first-principles computation, material synthesis, device fabrication, and characterization, will offer important interdisciplinary training to a diversified student body through targeted recruiting from underrepresented groups.This proposal aims to demonstrate the first chalcogenide perovskite-based light emitting diodes, with the long-term goal of bridging the green gap in LED technology. This will involve an iterative process in which theoretical prediction will guide material synthesis and atomic level structural, optical, and carrier transport characterization will inform theoretical models as well as device design and fabrication. The idea of this work was conceived based on the principal investigators' recent prediction and realization of chalcogenide perovskite materials with tunable band gap and promising semiconducting properties. The specific project objectives are to: i) Develop a low temperature chalcogenide perovskite thin-film processing technique compatible with device fabrication and growing high quality SrHfS3 and SrZrS3 thin films with strong green and amber light emission. ii) Control device properties through concerted first-principles computation and experiments of atomic scale structural, optical, and carrier transport characteristic. iii) Design, fabricate, and evaluate green and amber LEDs from n- and p- type doped SrHfS3 and SrZrS3 thin films. An innovative device fabrication technique incorporating micro-transfer-printing allows for dissimilar materials to form a high-quality p-i-n type LED structure with extremely clean interfaces without being constrained by their growth conditions.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.