Planar defect-free pure red perovskite light-emitting diodes via metastable phase crystallization

Yong-Hui Song; Jing Ge; Li-Bo Mao; Kun-Hua Wang; Xiao-Lin Tai; Qian Zhang; Le Tang; Jing-Ming Hao; Ji-Song Yao; Jing-Jing Wang; Tao Ma; Jun-Nan Yang; Yi-Feng Lan; Xue-Chen Ru; Li-Zhe Feng; Guozhen Zhang; Yue Lin; Qun Zhang; Hong-Bin Yao

doi:10.1126/sciadv.abq2321

Planar defect-free pure red perovskite light-emitting diodes via metastable phase crystallization

Sci Adv. 2022 Nov 11;8(45):eabq2321. doi: 10.1126/sciadv.abq2321. Epub 2022 Nov 11.

Authors

Yong-Hui Song^{1

2}, Jing Ge^{1

3}, Li-Bo Mao¹, Kun-Hua Wang¹, Xiao-Lin Tai¹, Qian Zhang^{1

2}, Le Tang³, Jing-Ming Hao^{1

2}, Ji-Song Yao^{1

2}, Jing-Jing Wang^{1

2}, Tao Ma¹, Jun-Nan Yang², Yi-Feng Lan², Xue-Chen Ru¹, Li-Zhe Feng¹, Guozhen Zhang¹, Yue Lin¹, Qun Zhang^{1

3

4}, Hong-Bin Yao^{1

2}

Affiliations

¹ Hefei National Research Center for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026, China.
² Department of Applied Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, China.
³ Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
⁴ Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China.

Abstract

Solution-processable all-inorganic CsPbI_3-xBr_x perovskite holds great potential for pure red light-emitting diodes. However, the widely existing defects in this mixed halide perovskite markedly limit the efficiency and stability of present light-emitting diode devices. We here identify that intragrain Ruddlesden-Popper planar defects are primary forms of such defects in the CsPbI_3-xBr_x thin film owing to the lattice strain caused by inhomogeneous halogen ion distribution. To eliminate these defects, we develop a stepwise metastable phase crystallization strategy to minimize the CsPbI_3-xBr_x perovskite lattice strain, which brings planar defect-free CsPbI_3-xBr_x thin film with improved radiative recombination, narrowed emission band, and enhanced spectral stability. Using these high-quality thin films, we fabricate spectrally stable pure red perovskite light-emitting diodes, showing 17.8% external quantum efficiency and 9000 candela meter^-2 brightness with color coordinates required by Rec. 2020.