Efficient Green Spin Light-Emitting Diodes Enabled by Ultrafast Energy- and Spin-Funneling in Chiral Perovskites

Jingwen Yao; Zhiyu Wang; Yuling Huang; Jie Xue; Dengliang Zhang; Jiangshan Chen; Xihan Chen; Shou-Cheng Dong; Haipeng Lu

doi:10.1021/jacs.4c02821

Efficient Green Spin Light-Emitting Diodes Enabled by Ultrafast Energy- and Spin-Funneling in Chiral Perovskites

J Am Chem Soc. 2024 May 22;146(20):14157-14165. doi: 10.1021/jacs.4c02821. Epub 2024 May 10.

Authors

Jingwen Yao^{1

2

3}, Zhiyu Wang¹, Yuling Huang⁴, Jie Xue¹, Dengliang Zhang⁵, Jiangshan Chen⁵, Xihan Chen⁴, Shou-Cheng Dong^{2

3}, Haipeng Lu^{1

6}

Affiliations

¹ Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, 999077 Hong Kong (SAR), China.
² Institute for Advanced Study, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, 999077 Hong Kong (SAR), China.
³ State Key Laboratory of Advanced Displays and Optoelectronics Technologies, Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, 999077 Hong Kong (SAR), China.
⁴ Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China.
⁵ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, South China University of Technology, Guangzhou, Guangdong 510640, China.
⁶ Energy Institute, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, 999077 Hong Kong (SAR), China.

PMID: 38727602
DOI: 10.1021/jacs.4c02821

Abstract

Introducing molecular chirality into perovskite crystal structures has enabled the control of carrier spin states, giving rise to circularly polarized luminescence (CPL) in thin films and circularly polarized electroluminescence (CPEL) in LEDs. Spin-LEDs can be fabricated either through a spin-filtering layer enabled by chiral-induced spin selectivity or a chiral emissive layer. The former requires a high degree of spin polarization and a compatible spinterface for efficient spin injection, which might not be easily integrated into LEDs. Alternatively, a chiral emissive layer can also generate circularly polarized electroluminescence, but the efficiency remains low and the fundamental mechanism is elusive. In this work, we report an efficient green LED based on quasi-two-dimensional (quasi-2D) chiral perovskites as the emitting layer (EML), where CPEL is directly produced without separate carrier spin injection. The optimized chiral perovskite thin films exhibited strong CPL at 535 nm with a photoluminescence quantum yield (PLQY) of 91% and a photoluminescence dissymmetry factor (g_lum) of 8.6 × 10^-2. Efficient green spin-LEDs were successfully demonstrated, with a large EL dissymmetry factor (g_EL) of 7.8 × 10^-2 and a maximum external quantum efficiency (EQE) of 13.5% at room temperature. Ultrafast transient absorption (TA) spectroscopic study shows that the CPEL is generated from a rapid energy transfer accompanied by spin transfer from 2D to 3D perovskites. Our study not only demonstrates a reliable approach to achieve high performance spin-LEDs but also reveals the fundamental mechanism of CPEL with an emissive layer of chiral perovskites.