Short-branched alkyl sulfobetaine-passivated CsPbBr3 nanocrystals for efficient green light emitting diodes

Lian-Yue Li; Yong-Hui Song; Jun-Nan Yang; Xue-Chen Ru; Yi-Chen Yin; Hong-Bin Yao

doi:10.1039/d4nr00965g

Short-branched alkyl sulfobetaine-passivated CsPbBr₃ nanocrystals for efficient green light emitting diodes

Nanoscale. 2024 Apr 18;16(15):7387-7395. doi: 10.1039/d4nr00965g.

Authors

Lian-Yue Li^{1

2}, Yong-Hui Song^{1

2}, Jun-Nan Yang^{1

2}, Xue-Chen Ru^{1

2}, Yi-Chen Yin^{1

2}, 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. yhb@ustc.edu.cn.
² Department of Applied Chemistry, Hefei Science Center of Chinese Academy of Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.

PMID: 38545886
DOI: 10.1039/d4nr00965g

Abstract

Inorganic cesium lead bromide nanocrystals (CsPbBr₃ NCs) hold promising prospects for high performance green light-emitting diodes (LEDs) due to their exceptional color purity and high luminescence efficiency. However, the common ligands employed for passivating these indispensable NCs, such as long-chain organic ligands like oleic acid and oleylamine (OA/OAm), display highly dynamic binding and electronic insulating issues, thereby resulting in a low efficiency of the as-fabricated LEDs. Herein, we report a new zwitterionic short-branched alkyl sulfobetaine ligand, namely trioctyl(propyl-3-sulfonate) ammonium betaine (TOAB), to in situ passivate CsPbBr₃ NCs via a feasible one-step solution synthesis, enabling efficiency improvement of CsPbBr₃ NC-based LEDs. The zwitterionic TOAB ligand not only strengthened the surface passivation of CsPbBr₃ NCs with a high photoluminescence quantum yield (PLQY) of 97%, but also enhanced the carrier transport in the fabricated CsPbBr₃ NC thin films due to the short-branched alkyl design. Consequently, CsPbBr₃ NCs passivated with TOAB achieved a green LED with an external quantum efficiency (EQE) of 7.3% and a maximum luminance of 5716 cd m^-2, surpassing those of LEDs based on insulating long-chain ligand-passivated NCs. Our work provides an effective surface passivation ligand design to enhance the performance of CsPbBr₃ NC-based LEDs.