报告时间：2024年8月17日（星期六）14:00

报告地点：科技D楼1903会议室

邀  请  人：吕  刚  教授

报告一：The Power of One: From single molecule investigations to materials research and beyond

报告人：Prof. Johan Hofkens

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. 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. I will focus on our perovskite research line and demonstrate how, starting from blinking of perovskite nanocrystal blinking, we developed a new imaging modality that allows for studying perovskite-based devices in situ and in operando¹. I also will shed light on the curious (photo)physics of perovskites². Next I will show how our unique single molecule equipment was tailored to investigate photon exchange between colloidal particles, which has resulted in an intense research effort into optical binding³.

Key Words: Single molecule imaging, Optical mapping, Optical binding, Perovskites

References:

1. Louis B, Seth S, An Q, Ji R, Vaynzof Y, Hofkens J, et al. Correlation Clustering Imaging: A method for Functional Mapping of Semiconductor materials and photovoltaic devices in operando. ChemRxiv. 2024; doi:10.26434/chemrxiv-2024-76908

2. Heng Zhang, Elke Debroye, Beatriz Vina-Bausa, Donato Valli, Shuai Fu, Wenhao Zheng, Lucia Di Virgilio, Lei Gao, Jarvist M Frost, Aron Walsh, Johan Hofkens, Hai I Wang, Mischa Bonn. Stable Mott Polaron State Limits the Charge Density in Lead Halide Perovskites. ACS Energy Letters 2022; 8, 420-428

3. Huang, CH., Louis, B., Bresolí-Obach, R. et al. The primeval optical evolving matter by optical binding inside and outside the photon beam. Nat Commun 13, 5325 (2022). https://doi.org/10.1038/s41467-022-33070-w

个人简介

Johan Hofkens received his MSc. and Ph.D. degree in Chemistry from the University of Leuven (KULeuven). After postdoctoral research with Prof. Masuhara at Osaka University (1994-1995) and Prof. Barbara at the University of Minneapolis (1996), he rejoined the KULeuven, establishing the Single Molecule Laboratory in the group of Frans De schryver. In 2005 he was appointed Research Professor at the KULeuven and in 2008 he was promoted to full professor. His research interests are fast spectroscopy, single molecule spectroscopy & fluorescence microscopy, the development of new microscopy modes and application of these microscopy modalities in biological and materials research. He currently holds a fellow position in the MPI Mainz. Prof. Hofkens is an editor for ACS and serves on editorial boards of multiple journals.  He has published more than 500 journal research papers, holds 7 patents, co-authored two books. He is an elected Member of the Flemish Academy of Science (Vlaamse Koninklijke Academie voor Wetenschappen, Letteren en Kunst), of the European Academy of Science, and of  Academia Europaea. He received several awards including the Award of the ‘Koninklijke Academie voor Wetenschappen, Letteren en Kunst’, section Chemistry, the Grammaticakis Neumann award in Photochemistry, the ‘Prix FSR’, the Morino Lecturer award and the Otto Wolfbeis Fluorescence Prize. Prof Hofkens held the Zernike chair at the University of Groningen and holds a Chair professor position at Zhejiang University . He has mentored over 50 PhD students and over 80 postdocotoral researchers, many of which  now occupy positions in academia themselves.

报告二：Crystalline perovskite materials conquering the challenges toward stable optoelectronics

报告人：Prof. Elke Debroye

报告摘要

      Metal halide perovskites are a class of semiconductors that have garnered a tremendous amount of attention for application in optoelectronic devices. These low-cost materials exhibit outstanding properties, such as efficient light absorption, tunable emission, and good charge carrier transport. As an example, perovskites have accomplished a rapid rise in solar power conversion efficiency to over 25% in less than a decade, outperforming the conventional silicon solar cells. However, the fundamental understanding of their intrinsic properties related to their photophysical performance is lagging behind, but is necessary to improve the materials even more. Moreover, upon studying new perovskite materials for optoelectronic devices, it is often overlooked that it is not only important to evaluate their (superior) performance, but also their long-term stability. We have applied different synthesis strategies to obtain perovskite systems with a large variety in composition, structure, morphology, and sizes. I will discuss how we apply a set of advanced spectroscopic tools to detail the interplay of crystalline properties and charge carriers that govern the optoelectronic performance. Furthermore, I will highlight the importance of micro-engineering the perovskites’ chemistry, structure, and morphology toward an improved material platform for next-generation optoelectronics, with a focus on X-ray detector devices.

个人简介

Elke Debroye graduated as Master in Chemistry at KU Leuven in 2009 and obtained a PhD in bio-inorganic chemistry at KU Leuven in 2013 on developing novel MRI/ luminescent contrast agents. After that, she changed fields and became a postdoctoral fellow working on the synthesis and advanced characterization of semiconductor materials at the Laboratory for photochemistry and spectroscopy. After three long-term research visits with prof. Liz-Marzán in San Sebastian (Spain), prof. Majima at Osaka University (Japan) and prof. Bonn at MPI Mainz (Germany), she was appointed professor at KU Leuven in October 2021 within the Department of Chemistry (www.debroyegroup.com). She is an expert in the application of novel spectroscopy/ microscopy tools for in depth characterization of (in)organic semiconductor materials. Via this approach, she aims to rationalize the development of materials, in particular perovskite materials, with improved optoelectronic properties for application in photodetectors, catalysis, as well as LEDs. With her recently awarded ERC Starting Grant (2023-2028) she will further develop state-of-the-art characterization tools based on ultrafast spectroscopy to study the use of novel lead-free perovskites for X-ray detection.