ECCS-EPSRC: Superlattice Architectures for Efficient and Stable Perovskite LEDs

ECCS-EPSRC：用于高效稳定钙钛矿 LED 的超晶格架构

• 批准号: 2141949
• 负责人: Seth Marder
• 金额: $ 40万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2141949&HistoricalAwards=false
• 关键词: ECCS; EPSRC; Superlattice; Architectures; Efficient

This proposal will develop thin-film metal-halide perovskite light-emitting diodes (LEDs) with high efficiencies. Standard inorganic LEDs, such as blue indium-gallium nitride, rely on the ability to p-dope and n-dope the hole- and electron-injecting layers, and to construct multi-quantum-well structures within which electrons/holes are confined and emit light, all in a heteroepitaxial structure. This allows close to thermodynamic efficiency operation for red and blue, but not yet for green (where nitrides show substantial losses). In contrast, organic LEDs (OLEDs) are assembled as stacks of different molecular materials, with band-edge positions selected to allow electron or hole transport to the recombination zone. ‘Doping’ through charge-transfer reactions with redox-active additives is used to assist injection from electrodes, but is not possible in the bulk. Though commercialized for displays, OLEDs require drift fields to overcome injection barriers, show very low carrier mobilities, and operate at voltages well above the emission bandgap. As outlined in our ‘track-record’ above, the team successfully adopted the OLED architecture for thin-film LEDs made with metal-halide perovskites. The critical components in this work will be developing: (a) a 2D/3D superlattice that confines e-h pairs, but with a tuneable “well depth” in order to minimize drive voltage requirements will be used in these to achieve good charge trapping, (b) spacer layers of perovskite that keep charge carriers away from the transport layers to avoid quenching; (c) and (d) hole- and electron-transport layers engineered to give ohmic injection at the perovskite interfaces, through chemical tuning and doping (ensuring that trap/quenching states associated with doping are far enough away from the emissive perovskite zone) and designed to give ohmic contacts at the two electrodes. This requires advances across a range of materials chemistry, materials processing, and semiconductor engineering tasks, underpinned by advanced characterization techniques. Light-emitting diodes (LEDs) are devices that are used in many of today’s displays, such as those used in televisions and cell phones, and can also increasingly in lighting. For these applications red-, green-, and blue-emitting LEDs are needed. However, green-emitting LEDs that are energy efficient and that are stable are particularly challenging to develop. This proposal is focused on developing efficient green-emitting devices based on a class of materials known as metal-halide perovskites. In particular, teams at the Universities of Cambridge (UK), Oxford (UK), and Colorado (USA) will collaborate with one another to solve engineering problems facilitating such devices. This work may result in new commercially viable LED technologies, as well as other new applications for metal-halide perovskites. As well as having potential impacts on the emerging semiconductor industry in the UK and USA, this project will: provide a US postdoctoral researcher with experience in organic and metal-organic synthesis and a range of physical characterization methods, and with the opportunity to participate in a close international inter-institute collaboration; and help support the education and training of women and underrepresented minority students.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.

该建议将以高效率发展薄膜金属钙钛矿发光二极管（LED）。标准的无机LED（例如蓝色氮化氮化物）依赖于p-dope和n-dope的孔和电子注入层的能力，并构建了限制电子/孔的多量词 - 孔结构，所有这些结构都限制并发出光线，所有这些结构都具有异性上皮结构。这可以接近红色和蓝色的热力学效率操作，但尚未用于绿色（氮化物显示大量损失）。相反，将有机LED（OLED）组装成不同分子材料的堆栈，并选择了带边缘的位置以允许电子或孔传输到重组区。通过用氧化还原活性添加剂进行电荷转移反应的“掺杂”用于协助电子注入，但在整体中是不可能的。尽管商业化用于显示器，但OLED需要漂移场才能克服注射屏障，显示出非常低的载体迁移率，并且在远高于发射带盖的电压下运行。正如我们上面的“田径记录”中概述的那样，该团队成功地采用了用金属 - 甲基钙钛矿制成的薄膜LED的OLED建筑。这项工作中的关键组成部分将开发：（a）限制E-H对的2D/3D超级晶格，但是使用可调的“井深”，以最大程度地减少驱动电压要求，以实现良好的充电捕获，（b）（b）将电荷层远离运输层，以避免使用运输层，以避免使用运输层，以避免使用Quench; quench; （c）和（d）通过化学调整和掺杂（确保与掺杂相关的陷阱/淬火状态），孔和电子传输层设计为在钙钛矿界面进行欧姆注入，并远离发射的钙钛矿区域），并设计以在两种电极上给出欧姆的接触。这需要在一系列材料化学，材料处理和半导体工程任务中的进步，并以先进的特征技术为基础。发光的演讲（LED）是当今许多显示器中使用的设备，例如电视和手机中使用的设备，也可以增加照明。对于这些应用，需要红色，绿色和蓝色发射LED。但是，能节能且稳定的绿色发射LED特别挑战开发。该提案的重点是基于一种称为金属壁钙化物的材料开发有效的绿色发射设备。特别是，剑桥（英国），牛津（英国）和科罗拉多州（美国）大学的团队将彼此合作，以解决支持此类设备的工程问题。这项工作可能会导致新的商业可行的LED技术，以及其他用于金属 - 甲基钙钛矿的新应用。除了对英国和美国的新兴半导体行业产生潜在影响，该项目还将：为美国的博士后研究人员提供有机和金属有机合成和一系列物理表征方法的经验，并有机会参加紧密的国际互联网协作；该奖项反映了NSF的法定任务，并帮助支持妇女和代表性不足的少数民族学生的教育和培训，并通过使用基金会的知识分子优点和更广泛的影响评估标准来评估，被认为是珍贵的支持。