Chlorine Vacancy Passivation in Mixed Halide Perovskite Quantum Dots by Organic Pseudohalides Enables Efficient Rec. 2020 Blue Light-Emitting Diodes

Xiaopeng Zheng, Shuai Yuan, Jiakai Liu, Jun Yin, Fanglong Yuan, Wan Shan Shen, Kexin Yao, Mingyang Wei, Chun Zhou, Kepeng Song, Bin Bin Zhang, Yuanbao Lin, Mohamed Nejib Hedhili, Nimer Wehbe, Yu Han, Hong Tao Sun, Zheng Hong Lu, Thomas D. Anthopoulos, Omar F. Mohammed, Edward H. SargentLiang Sheng Liao, Osman M. Bakr

Research output: Journal article publicationJournal articleAcademic researchpeer-review

127 Citations (Scopus)

Abstract

Blue-emitting perovskites can be easily attained by precisely tuning the halide ratio of mixed halide (Br/Cl) perovskites (MHPs). However, the adjustable halide ratio hinders the passivation of Cl vacancies, the main source of trap states leading to inferior performance of blue MHP light-emitting diodes (LEDs). Here, we report a strategy for passivating Cl vacancies in MHP quantum dots (QDs) using nonpolar solvent-soluble organic pseudohalide [n-dodecylammonium thiocyanate (DAT)], enabling blue MHP LEDs with greatly enhanced efficiency. Density functional theory calculations reveal that the thiocyanate (SCN-) groups fill in the Cl vacancies and remove electron traps within the bandgap. DAT-treated CsPb(BrxCl1-x)3 QDs exhibit near unity (∼100%) photoluminescence quantum yields, and their blue (∼470 nm) LEDs are spectrally stable with an external quantum efficiency of 6.3%, a record for perovskite LEDs emitting in the range of 460-480 nm relevant to Rec. 2020 display standards, and a half-lifetime of ∼99 s.

Original languageEnglish
Pages (from-to)793-798
Number of pages6
JournalACS Energy Letters
Volume5
Issue number3
DOIs
Publication statusPublished - 13 Mar 2020

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Materials Chemistry

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