Moore and More ›› 2025, Vol. 1 ›› Issue (3): 199-207.DOI: 10.1007/s44275-024-00018-9

• Original Article •     Next Articles

Mitigating interfacial carrier crowding by an ultrathin LiF interlayer towards efficient and stable perovskite light-emitting diodes

Xiaofei Zhang1, Lin Wang1, Lingmei Kong1, Sheng Wang1, Jun Dai3, Guohua Jia4, Xuyong Yang1,2   

  1. 1. Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai, 200072, China;
    2. Shanghai Engineering Research Center for Integrated Circuits and Advanced Display Materials, Shanghai University, Shanghai, 201899, China;
    3. Department of Physics, Jiangsu University of Science and Technology, Zhenjiang, 212100, Jiangsu, China;
    4. School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth, WA, 6845, Australia
  • Received:2024-07-12 Revised:2024-10-04 Accepted:2024-10-23 Online:2025-11-29 Published:2024-12-26
  • Contact: Lin Wang,E-mail:lin_wang@shu.edu.cn;Xuyong Yang,E-mail:yangxy@shu.edu.cn
  • Supported by:
    This work was supported by the financial support of the National Natural Science Foundation of China (62174104), the Shanghai Science and Technology Committee (22YF1413500), Program of Shanghai Academic/Technology Research Leader (22XD1421200), and Natural Science Foundation of Shanghai (23ZR1423300).

Mitigating interfacial carrier crowding by an ultrathin LiF interlayer towards efficient and stable perovskite light-emitting diodes

Xiaofei Zhang1, Lin Wang1, Lingmei Kong1, Sheng Wang1, Jun Dai3, Guohua Jia4, Xuyong Yang1,2   

  1. 1. Key Laboratory of Advanced Display and System Applications of Ministry of Education, Shanghai University, Shanghai, 200072, China;
    2. Shanghai Engineering Research Center for Integrated Circuits and Advanced Display Materials, Shanghai University, Shanghai, 201899, China;
    3. Department of Physics, Jiangsu University of Science and Technology, Zhenjiang, 212100, Jiangsu, China;
    4. School of Molecular and Life Sciences, Curtin University, GPO Box U1987, Perth, WA, 6845, Australia
  • 通讯作者: Lin Wang,E-mail:lin_wang@shu.edu.cn;Xuyong Yang,E-mail:yangxy@shu.edu.cn
  • 作者简介:Xiaofei Zhang graduated from Hebei Normal University in 2020 with a bachelor’s degree. She obtained her master's degree from Jiangsu University of Science and Technology in 2023. She is currently a Ph.D. candidate supervised by Prof. Xuyong Yang. Her research focuses on perovskite light-emitting devices.
    Lin Wang received her Ph.D. degree in nanomaterials and devices from Hubei University in 2018. After postdoctoral training in the group of Prof. Handong Sun in Nanyang Technological University, Singapore, she joined the Key Laboratory of Advanced Display and System Applications of Ministry of Education of Shanghai University as an assistant professor in 2020. Her research interests include the fabrication of semiconductor light-emitting nanomaterials and their optoelectronic devices.
    Lingmei Kong received her master’s and Ph.D. degree from Shanghai University in 2021 and 2024, respectively. Her research work focuses on preparation of low dimensional semiconductor nanomaterials and their applications in light-emitting devices.
    Sheng Wang received his Ph.D. degree from Jilin University. Then he joined the Key Laboratory of Advanced Display and System Applications of the Ministry of Education of Shanghai University as a postdoctoral fellow. He is now a lecturer at Shanghai University and his research interest is nanometer materials.
    Jun Dai is the executive dean of the School of Science, Jiangsu University of Science and Technology. He obtained his Ph.D. degree from Southeast University in 2012. He then went to Nanyang Technological University as a visiting scholar in 2010–2011, and subsequently went to the University of WisconsinMadison as a visiting scholar in 2015–2016. His research interests include semiconductor optics.
    Guohua Jia is an associate professor at Curtin University, Australia. He obtained his Ph.D. degree in chemistry in 2009 from City University of Hong Kong and subsequently worked as a postdoctoral fellow with Prof. Uri Banin at the Hebrew University of Jerusalem, Israel from 2010 to 2014. He commenced his current role as a group leader at Curtin University in 2015. His research interests focus on chemistry and physics of semiconductor nanocrystals, with particular emphasis on their properties and application in optoelectronic devices.
    Xuyong Yang is a full professor at Shanghai University, China. He received his Ph.D. degree in microelectronics from Nanyang Technological University in Singapore in 2014, and worked as a postdoc at the same university prior to beginning his independent research career at Shanghai University. His research focuses primarily on design and fabrication of low dimensional semiconductor nanomaterials such as quantum dots and perovskite nanocrystals, as well as their applications in light-emitting devices.
  • 基金资助:
    This work was supported by the financial support of the National Natural Science Foundation of China (62174104), the Shanghai Science and Technology Committee (22YF1413500), Program of Shanghai Academic/Technology Research Leader (22XD1421200), and Natural Science Foundation of Shanghai (23ZR1423300).

Abstract: Quasi-two-dimensional (quasi-2D) perovskite-based light-emitting diodes (PeLEDs) have attracted intensive attention due to their high quantum yields, tunable emission wavelengths, and solution-processing capability, showing great potential in next-generation display and lighting applications. However, further performance enhancement in PeLEDs is severely limited by the uncontrolled transfer of charge carriers under bias, leading to crowding of interfacial carriers and severe efficiency roll-off. Herein, we insert an ultra-thin dielectric buffer layer of lithium fluoride (LiF) into the electron transport layer (ETL) to regulate the transfer dynamics of electrons and passivate the interfacial defects simultaneously. The dielectric LiF interlayer can effectively reduce the efficiency roll-off in PeLEDs by improving the charge balance through preventing the overwhelming injection of electrons. Moreover, the fluoride anions from LiF can passivate the surface defects of the perovskite film, enhancing the radiative recombination. As a result, the LiF interlayer-assisted quasi-2D PeLED presents an outstanding external quantum efficiency (EQE) of 24.03% and a maximum brightness of 30 845 cd m-2. The operational stability of the device is also extended, with a half-lifetime (T50) of 71.28 min (at an initial luminance of 1 000 cd m-2), which is 7.4-fold longer than that for the control device.

Key words: Perovskite light-emitting diodes, Efficiency roll-off, LiF interlayer, Charge balance, Defect passivation

摘要: Quasi-two-dimensional (quasi-2D) perovskite-based light-emitting diodes (PeLEDs) have attracted intensive attention due to their high quantum yields, tunable emission wavelengths, and solution-processing capability, showing great potential in next-generation display and lighting applications. However, further performance enhancement in PeLEDs is severely limited by the uncontrolled transfer of charge carriers under bias, leading to crowding of interfacial carriers and severe efficiency roll-off. Herein, we insert an ultra-thin dielectric buffer layer of lithium fluoride (LiF) into the electron transport layer (ETL) to regulate the transfer dynamics of electrons and passivate the interfacial defects simultaneously. The dielectric LiF interlayer can effectively reduce the efficiency roll-off in PeLEDs by improving the charge balance through preventing the overwhelming injection of electrons. Moreover, the fluoride anions from LiF can passivate the surface defects of the perovskite film, enhancing the radiative recombination. As a result, the LiF interlayer-assisted quasi-2D PeLED presents an outstanding external quantum efficiency (EQE) of 24.03% and a maximum brightness of 30 845 cd m-2. The operational stability of the device is also extended, with a half-lifetime (T50) of 71.28 min (at an initial luminance of 1 000 cd m-2), which is 7.4-fold longer than that for the control device.

关键词: Perovskite light-emitting diodes, Efficiency roll-off, LiF interlayer, Charge balance, Defect passivation