题目:

Two-Dimensional Organic-Perovskites Hybrid Materials and Heterostructures

讲座人:

窦乐添（Letian Dou）助理教授

Davidson School of Chemical Engineering, Purdue University

Birck Nanotechnology Center, Purdue University（普渡大学）

时间:

7月29日（周三）上午9:00

地点:

腾讯会议（984 317 806）、随会（本院学生）

报告人简介：

窦乐添博士，普渡大学化学工程系助理教授，2009年获得北京大学学士学位后，加入加州大学洛杉矶分校材料科学与工程系杨阳教授团队，并于2014年获得博士学位（2013年受Fred Wudl教授共同指导）。2014-2017年，在加州大学伯克利分校和劳伦斯伯克利国家实验室材料科学部杨培东教授课题组完成博士后研究。他的研究兴趣包括：有机-无机杂化材料和低维材料的设计合成及构效关系的基本理解，以及在高性能电子和光电器件中的应用。2019年获海军研究办公室青年研究者奖，同年入选跨领域高被引学者，并曾获得麻省理工学院技术评论中国创新奖（2018）和MRS研究生奖（2014）。目前已发表研究论文50余篇，被引超15000次

报告简介：Halide perovskites are exciting new semiconductors that show great promising in low cost and high-performance optoelectronics devices including solar cells, LEDs, photodetectors, transistors,etc. However, these materials suffer from poor stability due to undesired chemical decomposition, ion migration, and phase transition. In this talk, I will present our “organic-perovskite hybrid” approach to address these fundamental stability issues as well as to create never-before-seen multi-complex semiconductor heterostructures. A new molecular design strategy for the synthesis of high-quality 2D organic-perovskite hybrid quantum wells through incorporating widely tunable organic semiconducting building blocks will be introduced. Ultrafast charge and energy transfer between the organic and inorganic components were revealed using state-of-the-art time-resolved spectroscopic methods. Next, I will present an effective strategy to substantially increase the stability and inhibit in-plane ion diffusion in the 2D hybrid perovskites. For the first time, we demonstrate highly stable and widely tunable lateral epitaxial heterostructures, multi-heterostructures, and superlattices of 2D hybrid perovskites via a solution-phase synthetic strategy. Near atomically sharp interfaces and epitaxial growth are revealed from low dose aberration-corrected high-resolution transmission electron microscopy (AC-HRTEM) characterizations. Molecular dynamics (MD) simulations reveal that the suppressed ion diffusivity is attributed to a combination of reduced heterostructure disorder and larger vacancy formation energies for 2D perovskites incorporating conjugated organic moieties. These findings represent critical fundamental insights into the immobilization and stabilization of halide perovskite semiconductor materials and provide a new materials platform for complex and molecularly thin superlattices, devices, and integrated circuits.