Color-pure red light-emitting diodes based on two-dimensional lead-free perovskites

Fanglong Yuan; Xiaopeng Zheng; Andrew Johnston; Ya-Kun Wang; Chun Zhou; Yitong Dong; Bin Chen; Haijie Chen; James Z Fan; Geetu Sharma; Peicheng Li; Yuan Gao; Oleksandr Voznyy; Hao-Ting Kung; Zheng-Hong Lu; Osman M Bakr; Edward H Sargent

doi:10.1126/sciadv.abb0253

Color-pure red light-emitting diodes based on two-dimensional lead-free perovskites

Sci Adv. 2020 Oct 14;6(42):eabb0253. doi: 10.1126/sciadv.abb0253. Print 2020 Oct.

Authors

Fanglong Yuan^{1

2}, Xiaopeng Zheng³, Andrew Johnston¹, Ya-Kun Wang¹, Chun Zhou¹, Yitong Dong¹, Bin Chen¹, Haijie Chen¹, James Z Fan¹, Geetu Sharma⁴, Peicheng Li², Yuan Gao¹, Oleksandr Voznyy⁴, Hao-Ting Kung², Zheng-Hong Lu⁵, Osman M Bakr⁶, Edward H Sargent⁷

Affiliations

¹ Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada.
² Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario M5S 3E4, Canada.
³ Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia.
⁴ Department of Physical and Environmental Sciences, University of Toronto, Scarborough 1065 Military Trail, Toronto, Ontario M1C 1A4, Canada.
⁵ Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario M5S 3E4, Canada. [email protected] [email protected] [email protected].
⁶ Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia. [email protected] [email protected] [email protected].
⁷ Department of Electrical and Computer Engineering, University of Toronto, 35 St George Street, Toronto, Ontario M5S 1A4, Canada. [email protected] [email protected] [email protected].

Abstract

It remains a central challenge to the information display community to develop red light-emitting diodes (LEDs) that meet demanding color coordinate requirements for wide color gamut displays. Here, we report high-efficiency, lead-free (PEA)₂SnI₄ perovskite LEDs (PeLEDs) with color coordinates (0.708, 0.292) that fulfill the Rec. 2100 specification for red emitters. Using valeric acid (VA)-which we show to be strongly coordinated to Sn²⁺-we slow the crystallization rate of the perovskite, improving the film morphology. The incorporation of VA also protects tin from undesired oxidation during the film-forming process. The improved films and the reduced Sn⁴⁺ content enable PeLEDs with an external quantum efficiency of 5% and an operating half-life exceeding 15 hours at an initial brightness of 20 cd/m² This work illustrates the potential of Cd- and Pb-free PeLEDs for display technology.

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