报告题目：Structural Insights into Organic Thin Films and Solar Cells: from Nanomorphology to Nano-crystallites Evolution

报  告  人：Dr. Wu, Mingjian, Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany

报告时间：2023年8月24日（星期四）上午10:00

报告地点：物理所 M楼249会议室

邀  请  人：陈震 特聘研究员 （82649878）

Abstract：

Harnessing the complex nano-scale structure in organic thin films is essential to tailor their functionality and performance. For example, the orientation of π-stacking domains and grain boundaries are essential to their electric transport properties in organic field-effect transistors; in bulk hetero-junction organic solar cells (OSCs) it determines exciton dissociation and charge carrier pathways thus dictating performance of the cells. Directly imaging the complex nano-structures in organic thin films using transmission electron microscopy (TEM) is highly challenging due to beam damage. In this talk, I will report our effort towards systematically characterizing the structure of OSCs and organic thin films using TEM: from nanomorphology using analytical methods, evaluating their textures with EF-SAED tomography, and finally emphasize probing local structure information with our recently proposed dose-efficient method 4D-scanning confocal electron diffraction (4D-SCED). Furthermore, I will discuss the merit when this technique is coupled to a state-of-the-art hybrid-pixel direct electron detector. The unique combination of high dose efficiency and high angular resolution makes 4D-SCED an ideal technique for studying the complex nanoscale structure of beam-sensitive organic thin films and solar cells.

Brief CV of Dr. Mingjian Wu :

Mingjian Wu is an enthusiastic “nano-photographer” with decade-long experience developing and application of cutting-edge electron microscopy, diffraction, and spectroscopy techniques combined with in situ/operando approaches and data science tools to obtain unique insights in a wide spectrum of modern functional materials. Shortly after his doctor degree from Humboldt University of Berlin, Germany with a top honor grade “summa cum laude”, he joined the Institute of Micro- and Nanostructure Research at University Erlangen-Nurnberg (FAU), Germany in 2015. He was later promoted to staff scientist there and is currently a senior staff scientist, supervising two state-of-the-art TEM instruments. He has published ~50 peer reviewed articles in international renewed journals. He is one of the three awardee of “Outstanding Paper Award” from the European Microscopy Society in 2022.