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 N. Hedhili, Nimer Wehbe, Yu Han, Hong-Tao Sun, Zheng-Hong Lu, Thomas D. Anthopoulos, Omar F. Mohammed, Edward H. SargentLiang-Sheng Liao, Osman Bakr

Research output: Contribution to journalArticlepeer-review

61 Scopus citations

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 lightemitting 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 halflifetime of ∼99 s.
Original languageEnglish (US)
Pages (from-to)793-798
Number of pages6
JournalACS Energy Letters
DOIs
StatePublished - Feb 11 2020

Fingerprint

Dive into the research topics of 'Chlorine Vacancy Passivation in Mixed-Halide Perovskite Quantum Dots by Organic Pseudohalides Enables Efficient Rec. 2020 Blue Light-Emitting Diodes'. Together they form a unique fingerprint.

Cite this