Chlorine Vacancy Passivation in Mixed-Halide Perovskite Quantum Dots by Organic Pseudohalides Enables Efficient Rec. 2020 Blue Light-Emitting Diodes
Hedhili, Mohamed N.
Anthopoulos, Thomas D.
Mohammed, Omar F.
Sargent, Edward H.
KAUST DepartmentAdvanced Membranes and Porous Materials Research Center
Chemical Science Program
Functional Nanomaterials Lab (FuNL)
KAUST Catalysis Center (KCC)
KAUST Solar Center (KSC)
Material Science and Engineering
Material Science and Engineering Program
Nanostructured Functional Materials (NFM) laboratory
Physical Science and Engineering (PSE) Division
Ultrafast Laser Spectroscopy and Four-dimensional Electron Imaging Research Group
Online Publication Date2020-02-11
Print Publication Date2020-03-13
Embargo End Date2021-02-11
Permanent link to this recordhttp://hdl.handle.net/10754/661562
MetadataShow full item record
AbstractBlue-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.
CitationZheng, X., Yuan, S., Liu, J., Yin, J., Yuan, F., Shen, W.-S., … Bakr, O. M. (2020). Chlorine Vacancy Passivation in Mixed-Halide Perovskite Quantum Dots by Organic Pseudohalides Enables Efficient Rec. 2020 Blue Light-Emitting Diodes. ACS Energy Letters. doi:10.1021/acsenergylett.0c00057
SponsorsThe authors acknowledge the funding support from KAUST, the National Natural Science Foundation of China (Grants 61575136 and 51773141), and the Collaborative Innovation Centre of Suzhou Nano Science and Technology (Nano-CIC) by the Priority Academic Program. E.H.S. and all co-authors from the Department of Electrical and Computer Engineering at the University of Toronto acknowledge the financial support from the Ontario Research Fund−Research Excellence Program and from the Natural Sciences and Engineering Research Council of Canada (NSERC).
PublisherAmerican Chemical Society (ACS)
JournalACS Energy Letters