关于举行瑞典林雪平大学Magnus Jonsson教授，赵丹副教授，旷超阳博士和英国剑桥大学陈尚志博士学术报告的通知
报告题目1：Controlling light at the nanoscale with conducting polymers
报 告 人：Magnus Jonsson教授（林雪平大学）
报告题目2：Ionic thermoelectrics and other related activities
报 告 人：赵丹 副教授（林雪平大学）
报告题目3：Tunable structural colouration based on electrochromic conducting polymers
报 告 人：陈尚志 博士 （剑桥大学）
报告题目4：Conducting polymer-cellulose devices for tunable infrared and THz optics
报 告 人：旷超阳 博士（林雪平大学）
邀 请 人：马於光 院士
报告时间：2023年12月28日（周四）14:30-17:30
报告地点：北区科技园1号楼502会议室
嘉宾简介&报告摘要：
1. Magnus Jonsson教授，2011年博士毕业于瑞典查尔姆斯大学，随后加入荷兰代尔夫特大学Cees Dekker实验室从事博士后研究，2014年加入林雪平大学有机电子实验室，2016年通过docent答辩成为博导，2019年入选瓦伦堡青年院士, 2020年入选瑞典研究理事会整合受资助者，2023年获欧盟基金会资助。研究方向为纳米光子及纳米光学机理研究以及相关器件在传感、显示、能源以及智能材料方面的应用。
Conducting polymers offer unique ways to control light and heat, which I will illustrate using three examples from our recent research.
I will first introduce our research showing that conducting polymers enable a new type of dynamically tuneable antennas for light. Such optical nanoantennas are important for many applications, including as building blocks for next generation of optical components called metasurfaces, which are flat and ultrathin. While traditional metasurfaces are limited to static functions because their nanoantennas are made of materials with fixed material properties, the optical response of conducting polymer nanoantennas and metasurfaces can be greatly tuned by varying the oxidation state of the polymer.
Next, I will demonstrate how conducting polymers offer novel means for forming materials with electrically controlled structural colours. Such materials are important for applications such as energy-effective reflective displays in colour. I will describe how we can achieve materials with such properties by combining electroactive functions of conducting polymers with structural coloration effects in thin films.
In the third example, we utilize the coldness of outer space to passively cool objects on Earth via thermal radiation. This concept, called passive radiative cooling, is explored world-wide as a sustainable complement to energy-consuming cooling methods like vapour-compression refrigeration. I will here focus on our recent research on using conducting polymers to electrically tune this concept, offering temperature regulation of objects at ambient conditions merely by tuning their ability to radiate heat.
2. 赵丹副教授，2008年本科毕业于南开大学，2013年1月博士毕业于中国人民大学，同年9月加入林雪平大学Reverant Crispin教授课题组从事博士后研究，研究方向为离子热电机理、铁电机理及相关器件应用。2017年获得瑞典VR启动基金成为助理教授，2021年至今为副教授，2022年12月通过docent答辩成为博导。
Ionic thermoelectric materials can generate large thermal voltages under temperature gradients while also being low-cost and environmentally friendly. Many electrolytes with large Seebeck coefficients have been reported in recent years, however, the mechanism of the thermal voltage has not been well understood. In this talk, we will start with introducing ionic thermoelectric materials and devices, followed by presenting our new discoveries of other facts that affect the measured thermal potential in ionic thermoelectric materials. 1) In thin film ionic thermoelectric devices, the absorbed water from atmosphere could greatly affect the apparent Seebeck coefficient. 2) The charge density and type (positive or negative) introduces additional potential to the device under temperature difference. 3) For sealed/bulky electrolytes, the Seebeck coefficient is related to the molar conductivity.
In the last part, other activities including ionic related thermal sensing and piezoelectrics will be shortly discussed.
3. 陈尚志博士，2012年本科毕业于上海交通大学，2014和2016年分别获得加拿大麦克斯特大学和比利时天主教鲁汶大学硕士学位，随后，加入林雪平大学Magnus Jonsson课题组开展博士研究，2021博士毕业后留组进行博士后研究，期间获得瑞典国王卡尔·古斯塔夫十六世科技研究基金和瑞典研究理事会(VR)博士后研究基金经费共计约250万人民币经费支持，2022年7月至今在英国剑桥大学Nanophotonics Centre做博士后研究，师从英国皇家科学院院士Prof. Jeremy J. Baumberg.
Precise manipulation of light-matter interactions has enabled various strategies to produce vibrant and non-fading structural colours. However, dynamic tuning structural colours across the visible spectrum with high brightness has proven to be a great challenge. Here, we present a novel method based on electrochromic conducting polymers and Fabry-Perot cavity structures, to create reflective colours that can be tunable throughout the entire visible range and beyond. The colour tuning mechanisms via electrochemistry can be attributed to the variation of the thin film thicknesses, the polymer’s complex refractive index, or a combination of both. In addition, we will demonstrate a novel film patterning techniques based on vapour phase polymerization and ultraviolet (UV) exposure, which could modulate the conducting polymer thin film thickness and refractive index synergistically. Combing this method with a greyscale photomask enables facile fabrication of high-resolution and multi-colour structural colour images within single steps. We believe our new proof-of-concept device structure and the UV-patterning method will be highly promising for the future electrochromic displays.
4. 旷超阳博士，2016年硕士毕业于宁波材料研究所硕士， 2017年获得国家公派博士奖学金加入林雪平大学高峰教授开始博士研究提高钙钛矿solar cell and LEDs器件的效率和稳定性2021年博士毕业，2022-05 加入Prof. Magnus Jonsson课题组继续博士后研究，发展可调控太赫兹和红外器件。
Terahertz (THz) technologies provide opportunities ranging from calibration targets for satellites and telescopes to communication devices and biomedical imaging systems. A main component will be broadband THz absorbers with switchability. However, optically switchable materials in THz are scarce and their modulation is mostly available at narrow bandwidths. Realizing materials with large and broadband modulation in absorption or transmission forms a critical challenge. This study demonstrates that conducting polymer-cellulose aerogels can provide modulation of broadband THz light with large modulation range from ≈ 13% to 91%, absolute transmission, while maintaining specular reflection loss < −30 dB. The exceptional THz modulation is associated with the anomalous optical conductivity peak of conducting polymers, which enhances the absorption in its oxidized state. The study also demonstrates the possibility to reduce the surface hydrophilicity by simple chemical modifications, and shows that broadband absorption of the aerogels at optical frequencies enables de-frosting by solar-induced heating. These low-cost, aqueous solution-processable, sustainable, and bio-friendly aerogels may find use in next-generation intelligent THz devices.
The Tunable infrared (IR) response of materials is important and desirable for many applications, including active camouflage, thermal management and anticounterfeiting. Current dominant IR-tunable systems exhibit limitations in practical tuning methods and mechanical properties or depend on complex and costly fabrication methods. Our device based on conducting polymer-cellulose papers, fabricated through a simple and cheap approach, can overcome such challenges.
