讲座主题：Comprehensive Interfacial Modifications for Improving the Efficiency and Stability of Rigid and Flexible Optoelectronics
主讲人： Wallace C. H. Choy, Department of Electrical and Electronic Engineering, The University of Hong Kong
邀请人：Future Organic Optoelectronics Research Centernics Research Center
时间： 2025.08.20 14:00 ~ 2025.08.20 15:00
地点： Room 200, Yue-Kong Pao Library's Annex
摘要：
Rigid and flexible organic and perovskite optoelectronics, such as solar cells (SCs), photodetectors (PDs), and light-emitting devices (LEDs), have been widely investigated for potential applications from solar farms to buildings and wearable electronics. Typically, flexible devices are multilayered structures composed of electrodes, carrier transport layers, and organic/perovskite active layers. The poor heterogeneous interfaces between different layers will cause various issues such as unexpected interlaminar stress and non-radiative recombination sites, degrading device efficiency and stability.
In this work, we introduce new approaches to modify the interface of two materials from electrodes to active layers to achieve highly efficient and stable PSCs. While typical transparent electrodes such as indium tin oxide (ITO) are costly and brittle, we develop an in-situ solution-processed method to achieve a new class of foldable transparent electrodes composed of metal-oxide nanoparticles (MONPs) and silver nanowires (AgNWs) [1] through the unique triple interfacial integrations, including (i) AgNW-AgNW, (ii) MONP-MONP, and (iii) AgNW-MONP interfaces. The foldable SCs show superior stability against mechanical-electrical-moisture operation with a folding radius as small as 0.75mm, humidity of 85%, and continuous electrical bias operations. Based on the new electrode, the foldable optoelectronic devices with very good stability against multi-loading (mechanical-electrical-moisture) operation with a folding radius as small as 0.75mm, humidity 85% and continuous electrical bias operations have been demonstrated. To further improve device performance, we have introduced several strategies to the perovskite interfaces by forming subsurface structures [2], which can significantly improve the electrical properties and stability of perovskite for SCs [3] and PDs [4, 5]. The perovskite SCs show power conversion efficiency of 25.8% and operational stability over 2000 hours [6]. The interface and active layer materials are also modified to improve the organic SC performances [7,8]. Meanwhile, we extend the ligand design [9-12] to enhance the mechanical stability by establishing ligand-termination surface structure on perovskites to reduce the Young’s modulus and thus achieve high efficiency and mechanically stable flexible/foldable perovskite LEDs [13,14].
[1] J. Kim, W.C.H. Choy, et al, Nature Commun., 15, 2070, 2024.
[2] Z.W. Gao, W.C.H. Choy, et. al, Joule 8, 1, 2024.
[3] Z.W. Wang, Y. An, X. Ren, H. Zhang, W.C.H. Choy, et al, Nature Commun, 15, 9647, 2024.
[4] H. Liu, L. Zhu, W.C.H. Choy*, et al., ACS Energy Lett., 8, 577, 2023.
[5] H. Liu, W.C.H. Choy*, et al., Adv. Mater., DOI: 10.1002/adma.202502191.
[6] Z.W. Gao, W.C.H. Choy, et al, Nature Photon., DOI: 10.1038/s41566-024-01596-8.PDS.
[7] X. He, W.C.H. Choy*, et al., Nature Comm., 15, 2103, 2024.
[8] Y. Yang, W.C.H. Choy*, et al., Energy Environ. Sci.,18, 1963, 2025.
[9] H. Lin, W. Choy*, et. al., Adv. Mater., 2008820, 2021.
[10] B. Lyu, W. Choy*, et. al., ACS Energy Lett., 8, 577,2023.
[11] D. Li ,W. Choy*, et. al., ACS Energy Lett., DOI:acsenergylett.4c00881.
[12] B. Lyu, W. Choy*, et. al., Angewandte Chemie, in press.
[13] C. Liu, W. Choy*, et al., Adv. Funct. Mater. 2024, 2404791.
[14] B. Lyu, D. Li, W.C.H. Choy*, et al., Adv. Mater., DOI: 10.1002/adma.202415211.
主讲人简介
Wallace C. H. Choy is a full professor in the Department of EEE, HKU. His research interests cover organic/inorganic optoelectronic devices, flexible and transparent conducting nanostructures, metal oxides, and nanomaterial devices. He has published over 270 peer-reviewed papers, several book chapters, patents, and edited one book. He was recognized as the top 1% of most-cited scientists in Thomson Reuter's Essential Science Indicators from 2014 to 2023.
He has served as a Member of the Engineering panels of the Hong Kong Research Grant Council (RGC), the Enterprise Support Scheme Assessment Panel of the Innovation and Technology Commission (ITC) of Hong Kong, the Ideation Programme and Incubation Programme of Hong Kong Science and Technology Parks Corporation (HKSTPC) and a Specialist of the Hong Kong Council for Accreditation of Academic and Vocational Qualifications (HKCAAVQ). He is an elected fellow of OSA/ Optica.
