应中国科学院广州能源研究所生物质高值化利用研究中心生物质催化转化科研团队邀请，比利时鲁汶大学Johan Hofkens教授将于4月3日9:30-11:30作学术报告，具体事项如下： 

一、时间及地点 

时间：4月3日9:30-11:30

地点：生物质能源大楼911会议室

二、报告题目及摘要

报告题目：From blinking of single molecule to looking in perovskite-based devices

报告摘要：

Single molecule spectroscopy has tremendously impacted every field in which the technique was applied,ranging from catalysis over plasmonics,polymer physics,biophysics to cell biology and DNA sequencing. Furthermore,single molecule techniques have allowed researchers to push the resolution of fluorescence microscopy past the diffraction limit,based on characteristic single molecule intermittence of fluorescence. In this presentation, I will give an overview of how recent single molecule experiments and development of new microscopy modalities in my laboratory have been impacted by material science and how these experiments have been driving developments in material science, with a focus on our perovskite research. Unlike conventional semiconductor materials, metal halide perovskites (MHP) possess soft and ionic crystal structures leading to several unique features like facile ion migration, self-healing, elasticity, and memory. Within this dynamic system, external stimuli like high photon doses, electron beams, electrical bias, and mechanical stress induce structural changes and alter associated optoelectronic properties. Therefore, it is crucial to investigate the structure-function relationship in these materials, especially in operational devices like solar cells, where traditional methods such as scanning electron microscopy fall short due to the layered structure. Moreover, electron and x-ray-based analytical techniques are often invasive altering the material properties.

To address these challenges, we developed Correlation Clustering Imaging (CLIM), a novel noninvasive method that utilizes photoluminescence fluctuations to reveal contrasts associated with defect dynamics in semiconductor materials. CLIM images of perovskite thin films show one-to-one matching with the grains in SEM images captured at the same locations. Particularly noteworthy is the application of CLIM to high-efficiency photovoltaic devices, uncovering previously unnoticed photoluminescence intensity fluctuations that strongly depend on the device's operational regime. Statistical analysis of these intensity fluctuations provides insights into the type of metastable defects responsible for fluctuating non-radiative recombination processes.

The insights gained from CLIM contribute to a deeper understanding of device efficiency,structure,and degradation,which are crucial for the rational engineering of the next generation of devices. The broad applicability of CLIM,requiring only a standard wide-field microscope and our user-friendly,open-source algorithm,positions it as an important new tool for material chemists,engineers,and device scientists .

三、报告人简介

Professor Johan Hofkens is a tenured professor in the Department of Chemistry at KU Leuven,Belgium,and a member of the European Academy of Sciences and the Royal Academy of Science and Arts of Belgium. He is dedicated to research in single-molecule spectroscopy,biophysics,catalytic energy conversion,and the development of novel perovskite materials,making him an internationally renowned molecular spectroscopist. He has published over 500 academic papers in top-tier international journals such as Science,Nature,and Cell. According to Web of Science,his work has been cited more than 30,000 times,with an H-index of 96. Google Scholar statistics indicate over 40,000 citations and an H-index of 110,reflecting his significant impact on research. He has received several awards,including the"Otto Wolfbeis Fluorescence Prize"and the"Proteomass Scientific Society Award."At KU Leuven,he has trained many outstanding doctoral students and postdoctoral researchers,possessing extensive teaching and mentoring experience. Professor Hofkens serves as a co-editor for ACS Omega and has been a member of the editorial boards for more than ten high-level SCI journals,including Chem and Chemical Science. He has also been a review expert for several projects,such as those funded by the European Research Council (ERC). Additionally,he has been a member of the advisory committee for various international conferences,including the International Conference on Photochemistry,and has served as a reviewer for dozens of high-impact journals,including Science,Nature,Nature Materials,Nature Methods,Nature Chemistry,Nature Communications,Physical Review Letters,Angewandte Chemie,Nano Letters,and ACS Nano.

欢迎感兴趣的科研人员和研究生参会。