报告题目: 钙钛矿电池有机空穴传输Spiro-OMeTAD的新型掺杂与理解

报告人：王锋（林雪萍大学副教授）

报告时间：2023年6月20上午10:00-11:30

报告地点：环境楼B4-308会议室

环境与能源学院

2023年6月15日

Abstract:

Perovskite solar cells (PSCs), as the third-generation PV materials, possess the unique advantages of solution-processable, lightweight, colorful, flexible, and thin-film technology in comparison to competing technologies.¹A key challenge for their practical applications lies in the inferior stability of devices, an issue determined by not only the perovskite materials² but also the charge transport layers³. Currently, most high-performance perovskite solar cells (PSCs) with > 24% PCE rely on the bench-mark hole transport layer (HTL), spiro-OMeTAD doped by lithium bis(trifluoromethane)sulfonimide (LiTFSI) and 4-tert-butylpyridine (tBP),which negatively affect the stability of devices.⁴ Additionally, the complex in-situ oxidation processes makes it challenging to understand the mechanism of conventional spiro-OMeTAD doping, and further limits the development of stable HTLs with high PCEs.

Here, I introduce a clean and free-post-oxidization doping recipe for spiro-OMeTAD by using stable organic radicals as the dopant and ionic salts as the doping modulator (referred to as ion-modulated (IM) radical doping)⁵.The doped spiro-OMeTAD based on our IM radical doping strategy delivered a high PCE of over 25% and excellent stability (T₈₀ for ~ 1200 h under 70±5% relative humidity and T₈₀ for ~ 800 h under 70±3 °C without encapsulation), minimizing the trade-off between efficiency and stability of PSCs. In this doping strategy, the radicals provide hole polarons that instantly increase the conductivity and work function, and ionic salts further modulate the work function (WF) by affecting the energetics of the hole polarons. More attractively, the IM radical doping strategy provides a facile yet effective approach to optimize separately the conductivity and WF of organic semiconductors for a variety of optoelectronic applications.

References:

1, J. Y. Kin, et al, Chem. Rev., 2020, 120, 15, 7867-7819.

2, J. Jeong, et al. Nature, 2021, 592(7854), 381-385.

3, M. Jeong, et al. Science, 2020, 369(6511), 1615-1620.

4, J. J. Yoo, et al. Nature, 2021, 590(7847), 587-593.

5, T. Zhang, F. Wang,* et al. Science, 2022, 377(6605), 495-501.

Brief Bio:

Feng Wang works as an Associate Professor at Linköping University (Sweden) since 2023. Before that, he was VINNMER Fellow (Sweden, 2017) and Marie Skłodowska-Curie Fellow (European Commission, 2018). He received supports from Swedish Research Council, STINT, Formas network grant, Olle Engkvists Stiftelse, and Carl Tryggers Stiftelse. His research interests focus on solar energy technologies based on lead-based perovskites, lead-free perovskites, and organic transport materials. Feng Wang has co-authored over 60 peer-reviewed publications on high impact journals (7000 citations and h-index 39), including Science, Science Advance, Advanced Materials, Angewandte Chemie, etc.

    王锋博士，瑞典林雪萍大学副教授。曾获2018年欧盟“玛丽·居里学者”（MSCA）。