cm0c00312_si_001.pdf (253.1 kB)
Spectral Tuning of Efficient CsPbBrxCl3–x Blue Light-Emitting Diodes via Halogen Exchange Triggered by Benzenesulfonates
journal contribution
posted on 2020-03-18, 13:03 authored by Fanghao Ye, Huijun Zhang, Pang Wang, Jinlong Cai, Liang Wang, Dan Liu, Tao WangCsPbX3 nanocrystal (NC)-based blue perovskite light-emitting
diodes (PeLEDs) are still in a backward position while their green
and red counterparts have achieved significant progress in the past
few years. The emission spectrum of perovskite NCs can be manipulated via the ratio control of halides in precursor or halogen
exchange of NCs. Herein, CsPbBrxCl3–x NCs are synthesized in ambient
condition. With tetrabutylammonium p-toluenesulfonate
(TBSA) added as the ligand during the purification process of as-synthesized
perovskite NCs, bromine in NCs is substituted by chlorine and the
spectrum undergoes a blue shift, whereas chlorine is exchanged by
bromine in NCs and the spectrum undergoes a red shift by introducing
sodium dodecylbenzenesulfonate (SDSA) as the ligand. The origin for
halogen exchange can be attributed to the synergistic effects of the
anion and cation of benzenesulfonates. The photoluminescence quantum
yield (PLQY) of NCs increases from 7% to 81% due to the effective
passivating effects of the strong ionic sulfonate heads, and the blue
PeLEDs prepared by this method show a promising external quantum efficiency
of 2.6%. Our work provides a new approach into spectral tuning of
efficient blue PeLEDs.