报告人：Prof. Hai Wang, Utrecht University
报告题目：Ultrafast Charge Carrier Dynamics in Novel Organic Semiconductors by THz Spectroscopy
报告时间：30th July (Thursday) 10:30 AM
报告地点：909-B厅
报告摘要：
The conversion of light into electrical currents is a fundamental process underlying the operation of various optoelectronic devices. Understanding the underlying photophysics, e.g., the generation and transport of charge carriers in photoactive materials following photoexcitation, is crucial for improving the energy conversion efficiency of these devices. Layered two-dimensional (2D) materials are emerging building blocks for next-generation electronics and optoelectronics. Since the discovery of graphene, the family of 2D materials has expanded significantly. The recent emergence of conductive semiconducting organic layers (e.g., graphene nanostructures and organic frameworks) has further extended the 2D materials library and introduced new functionalities for applications.
In this talk, I will first provide an overview of ultrafast THz spectroscopy and demonstrate its utility in characterizing the electrical transport properties of charge carriers in low-dimensional materials in a contact-free manner¹. I will then discuss recent work on understanding charge generation and transport mechanisms in novel organic semiconductors, including: (1) Giant exciton effects and hot exciton dissociation in graphene nanoribbons2-3, (2) how the intermolecular interactions impact on carrier (de)localization in organic crystalline systems4-6.
References
1. Wenhao Zheng et al., Nat. Phys. 18, 544–550 (2022).
2. Wenhao Zheng et al., Nat. Com. 17, 1201 (2026)
3. Alexander Tries et al., Nano Lett. 20, 2993–3002 (2020).
4. Guanzhao Wen et al., Nat. Comm. 17, 5260 (2026).
5. Shuai Fu et al., J. Am. Chem. Soc. 144, 7489–7496 (2022).
6. Shuai Fu et al., Nat. Comm. 16, 2219 (2025).
7. Mingchao Wang et al., Nat. Mater. 22, 880–887 (2023).
8. M. Giannini et al., Nat. Matt. 22, 1361-1369 (2023).
个人简介 ：
Hai Wang obtained his Bachelor in Materials Science at Zhejiang University (2007) and Master degree in nanoscience from KU Leuven and TU Delft (2011), supported by the Erasmus Mundus fellowship. In 2012-2016, Wang worked with Prof. dr. Mischa Bonn and Dr. Enrique Canovas to investigate ultrafast charge transfer processes at oxide interfaces at Max Planck Institute for Polymer Research and Mainz University. After 1 year in the group of Mathias Kläui at University of Mainz as a postdoc, Hai started leading the “Nano- optoelectronic materials” group in the Molecular Spectroscopy department at MPI-P in 2017, and further moved to Utrecht University as a tenured assistant professor in 2023. Employing time-resolved, ultrafast spectroscopies (in particular THz spectroscopy), the central theme of Hai’s current research lies in understanding fundamental charge carrier dynamics and low-energy excitations in solid-state low-dimensional materials and interfaces, relevant for energy and optoelectronic applications.
联系人：陈强 教授