来源:科学网 发布时间:2024/4/16 14:49:20
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香港大学、首尔国立大学等三位专家讲述分子生物学

直播时间:2024年4月16日(周二)20:00-22:00

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北京时间4月16日晚八点,iCANX Youth Talks第五十一期邀请到了香港大学Philip Chow,首尔国立大学Keehoon Kang,斯旺西大学 Emrys Evans三位教授主讲,北京大学Haixia Zhang作为主持人,香港科技大学(广州)Jiaying Wu,布里斯托大学Mike Price担任嘉宾,期待你一起加入这场知识盛宴。

【嘉宾介绍】

Philip Chow

香港大学

Mechanisms behind efficient and stable polymer solar cells

【Abstract】

The quest for sustainability and carbon neutrality calls for the development of low-cost and environmental-friendly solar photovoltaic technologies. Recently, the solar power conversion efficiencies of organic solar cells (OSC) have increased to 19%, closing the gap with inorganic and hybrid solar PV cells. The major breakthrough behind the great efficiency improvement is the development of non-fullerene acceptor molecules, replacing the traditional fullerene molecules as electron-accepting materials. Understanding the photophysical processes underlying these high-performance materials is crucial to OSC research. In this talk, I will present transient optical spectroscopy and structural analysis results on high-performance OSC blends based on state-of-the-art Y-type small molecule and polymeric acceptors. First, we found direct evidence that bound electron-hole pairs (excitons) separate at tens to hundreds of picoseconds via a thermally-activated (endothermic) process, which highlights the importance of achieving long (nanosecond) exciton lifetime at the donor-acceptor interface. Furthermore, we discovered that donor-acceptor percolation can play a key role in suppressing charge recombination at the interface, thereby allowing efficient charge generation. Crucially, such donor-acceptor percolation can also improve the thermodynamic stability of the blend morphology, thus pathing the way for OSC devices with both high device efficiency and stability.

为了实现可持续性和碳中和的需求,开发低成本且环保的太阳能光伏技术是至关重要的。最近,有机太阳能电池(OSC)的太阳能转换效率已提高至19%,大幅缩小了与无机和混合太阳能光伏电池的差距。这效率大幅提升背后的重大突破是新型非富勒烯受体分子的开发,取代了传统富勒烯分子作为电子受体材料。阐明这些高性能有机材料背后的光物理过程对于 OSC 研究至关重要。在本次演讲中,我将介绍基于最先进的 Y 型小分子和聚合物受体的高性能 OSC 共混物的瞬态光谱和结构分析结果。首先,我们的实验结果表明了激子是需要通过热激活(吸热)过程来分离成自由载流子,并凸显了在给体和受体界面实现纳秒级的激子寿命的重要性。此外,我们发现了给/受体在界面的渗滤可以有效抑制电荷复合,从而实现有效的电荷分离。重要的是,这种给/受体渗透还可以提高共混物形态的热力学稳定性,从而为实现高器件效率和稳定性的 OSC 器件开辟了新的可能性。

【BIOGRAPHY】

Philip C.Y. Chow received his B.Sc. from Imperial College London, and M.Phil. and Ph.D. in Physics from the University of Cambridge. He is currently an Assistant Professor in the Department of Mechanical Engineering at the University of Hong Kong (HKU). His multidisciplinary research group at HKU focuses on the study and development of polymer-based optoelectronic and photonic devices with applications in solar energy, wearable electronics and green buildings. He was awarded the UK EPSRC Doctoral Training Award in 2010, JSPS Overseas Postdoctoral Research Fellowship in 2016, the Hong Kong RGC Early Career Scheme in 2022, and the NSFC Excellent Young Scientist Fund in 2022.

周慈勇,香港大学机械工程系助理教授,于2010年本科毕业于帝国理工学院,2016年博士毕业于剑桥大学,2020年起任职于香港大学并在2022年获国家自然科学基金委优秀青年科学基金(港澳)资助。他在港大领导的跨学科课题组专注于研究和开发基于聚合物的光电和光子器件,并应用于太阳能、可穿戴电子产品和绿色建筑等。

Keehoon Kang

首尔国立大学

Overcoming Doping Challenges in Emerging Semiconductors

【ABSTRACT】

Doping has been one of the most essential methods to control charge carrier concentration in semiconductors. Excess generation of charge carriers is a key route for controlling electrical properties of semiconducting materials and typically accompanies alteration of electronic structure by the introduction of dopant impurities, both of which have played pivotal roles in making breakthroughs in inorganic microelectronic and optoelectronic devices both at research and industrial levels, especially for Si-based technology. Molecular doping is a facile and effective doping method for various semiconducting materials since it is relatively non-invasive compared to high-energy implantation of ionic impurities used in Si. However, there are main challenges remaining in fully utilising molecular doping in emerging semiconducting materials such as π-conjugated polymer semiconductors, two-dimensional materials and metal-halide perovskites due to the difficulties in preventing dopant-induced disorder effects while maintaining a high carrier mobility. This talk will introduce concepts that we have developed to minimizing the dopant-induced disorder while mitigating current injection and doping stability issues in electronic devices, and finally outline the future challenges remaining in the field to fully uncover the potentials.

掺杂一直是控制半导体中电荷载流子浓度的最基本方法之一。电荷载流子的过量生成是控制半导体材料电气性质的关键途径,通常伴随着通过引入掺杂杂质改变电子结构,这两者在使无机微电子和光电子设备在研究和工业层面取得突破方面发挥了关键作用,特别是对于基于硅的技术。分子掺杂是各种半导体材料的一种简便有效的掺杂方法,因为它相对于在硅中使用的离子杂质的高能植入来说,是相对非侵入性的。然而,在充分利用分子掺杂于新兴半导体材料(如π共轭聚合物半导体、二维材料和金属卤化物钙钛矿)方面仍存在主要挑战,因为在保持高载流子迁移率的同时,难以防止掺杂引起的无序效应。本次演讲将介绍我们开发的一些概念,以最小化掺杂引起的无序,同时缓解电流注入和掺杂稳定性问题,并最终概述该领域未来的挑战,以充分揭示其潜力。

【BIOGRAPHY】

Keehoon Kang is currently an assistant professor at Department of Materials Science and Engineering at Seoul National University, South Korea. He is an alumnus of the University of Cambridge, where he obtained his BA & MSci (combined) and PhD degrees in Physics in 2012 and 2017, respectively. After completing his postdoctoral research in the Department of Physics at Seoul National University, which also served as his military service substitution, he transitioned to a faculty position in the Department of Materials Science and Engineering at Yonsei University from 2021 to 2022. Currently, at Seoul National University, he is leading ONELab (Organic Next-gen Electronics) and is actively focused on the cutting-edge fields of mixed-ionic-electronic conducting organic semiconductors and metal-halide perovskites. His work is dedicated to exploring the fundamentals and developing new methods for controlling electrical properties of these novel materials for next-generation electronic and optoelectronic devices. He has been awarded numerous awards such as POSCO Science Fellowship (2019), Young Physicist Prize (2017) and he has served as a Young Advisory Board Member of InfoMat and InfoScience since 2023.

Keehoon Kang目前是韩国首尔国立大学材料科学与工程系的助理教授。他是剑桥大学的校友,在2012年和2017年分别获得了物理学的学士和博士学位。在完成首尔国立大学物理系的博士后研究后,该研究也作为他的兵役替代,他于2021年至2022年转到了延世大学材料科学与工程系的教职。目前,在首尔国立大学,他领导着ONELab(有机下一代电子),并积极专注于混合离子-电子导电有机半导体和金属卤化物钙钛矿的前沿领域。他的工作致力于探索这些新材料的基本性质,并开发新方法来控制下一代电子和光电子设备的电气性质。他曾获得多项奖项,如POSCO科学奖学金(2019年)、青年物理学家奖(2017年),自2023年以来,他还担任InfoMat和InfoScience的青年咨询委员会成员。

Emrys Evans

斯旺西大学

Exploiting Exciton and Spin Dynamics in Molecular Materials

【ABSTRACT】

The spin of ground and excited levels in molecular materials dictates the exciton mechanisms for any photonic, optoelectronic and quantum technology applications. This talk explores the photo- and spin physics of excitons as revealed by optical and magnetic resonance studies. Where molecules generally operate via singlet (spin, S = 0) and triplet (S = 1) excitons, our recent work on organic radicals containing unpaired electrons has explored efficient light absorption and emission from transitions between doublet (S = 1/2) and quartet (S = 3/2) excited states (Nature Materials 2020, Nature Communications 2022). As well as being potential candidates for functional emitters in light-emitting devices (Advanced Optical Materials 2022, Advanced Materials 2023), opportunities emerge to couple their optical, spin and magnetic properties in molecular excitons that could enable useful photon-spin interfaces (Nature 2023, JPCL 2024) for future sensing and networking applications.

分子材料中基态和激发态的自旋决定了光子学、光电子学和量子技术应用中的激子机制。本次演讲探讨了通过光学和磁共振研究揭示的激子的光物理和自旋物理。虽然分子通常通过单线态(自旋S=0)和三线态(S=1)激子运行,但我们最近对含有未配对电子的有机自由基的研究探索了从双重态(S=1/2)到四重态(S=3/2)激发态之间的高效光吸收和发射(Nature Materials 2020, Nature Communications 2022)。除了作为发光设备中功能性发射体的潜在候选者(Advanced Optical Materials 2022, Advanced Materials 2023)之外,还有机会将它们的光学、自旋和磁性性质耦合在分子激子中,这可能为未来的传感和网络应用启用有用的光子-自旋界面(Nature 2023, JPCL 2024)。

【BIOGRAPHY】

Emrys completed a DPhil in Chemistry at University of Oxford in 2016 with Professor Christiane Timmel. His DPhil was on the photo- and spin physics of light-induced electron transfer reactions implicated in animal magnetoreception. Following this he worked with Professor Sir Richard Friend at the Cavendish Laboratory, University of Cambridge as a Postdoctoral Research Associate (2016-2019). There he began researching molecular semiconductors for optoelectronics. He received a Leverhulme Trust Early Career Fellowship in 2019. In 2020 he started a Royal Society University Research Fellowship at Swansea University. In 2021 he was awarded the Dillwyn Medal for STEMM from the Learned Society of Wales. The design, characterization, and exploitation of optical and magnetic properties in new molecular materials is the focus of his research. Emrys is fluent in English, Welsh and Thai.

Emrys于2016年在牛津大学获得化学博士学位,师从Christiane Timmel教授。他的DPhil研究的是涉及动物磁感应的光诱导电子转移反应的光物理和自旋物理。此后,他在剑桥大学卡文迪什实验室与Sir Richard Friend教授合作,担任博士后研究助理(2016-2019)。在那里,他开始研究用于光电子学的分子半导体。2019年,他获得了Leverhulme Trust早期职业奖学金。2020年,他在斯旺西大学开始了皇家学会大学研究奖学金。2021年,他被授予威尔士学会的Dillwyn Medal for STEMM。他的研究重点是新分子材料的光学和磁性性质的设计、表征和利用。

【主持人】

Haixia Zhang

北京大学

【研讨嘉宾】

Jiaying Wu

香港科技大学(广州)

Mike Price

布里斯托大学

 
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