Self-assembled monolayer-based blue perovskite LEDs

Ya-Kun Wang; Fengyan Jia; Xiaoyue Li; Sam Teale; Pan Xia; Yuan Liu; Phoebe Tsz-Shan Chan; Haoyue Wan; Yasser Hassan; Muhammad Imran; Hao Chen; Luke Grater; Ling-Dong Sun; Gilbert C Walker; Sjoerd Hoogland; Zheng-Hong Lu; Chun-Hua Yan; Liang-Sheng Liao; Edward H Sargent

doi:10.1126/sciadv.adh2140

Self-assembled monolayer-based blue perovskite LEDs

Sci Adv. 2023 Sep 8;9(36):eadh2140. doi: 10.1126/sciadv.adh2140. Epub 2023 Sep 8.

Authors

Ya-Kun Wang^{1

2}, Fengyan Jia^{1

3}, Xiaoyue Li⁴, Sam Teale¹, Pan Xia¹, Yuan Liu¹, Phoebe Tsz-Shan Chan⁵, Haoyue Wan¹, Yasser Hassan^{1

6}, Muhammad Imran¹, Hao Chen¹, Luke Grater¹, Ling-Dong Sun³, Gilbert C Walker⁵, Sjoerd Hoogland¹, Zheng-Hong Lu⁴, Chun-Hua Yan³, Liang-Sheng Liao², Edward H Sargent¹

Affiliations

¹ Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, Ontario M5S 3G4, Canada.
² Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou, Jiangsu 215123, PR China.
³ Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, PKU-HKU Joint Laboratory in Rare Earth Materials and Bioinorganic Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
⁴ Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario M5S 3E4, Canada.
⁵ Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
⁶ Department of Chemistry and Earth Sciences, College of Arts and Sciences, Qatar University, P.O. Box: 2713, Doha, Qatar.

Abstract

Blue perovskite light-emitting diodes (LEDs) have shown external quantum efficiencies (EQEs) of more than 10%; however, devices that emit in the true blue-those that accord with the emission wavelength required for Rec. 2100 primary blue-have so far been limited to EQEs of ~6%. We focused here on true blue emitting CsPbBr₃ colloidal nanocrystals (c-NCs), finding in early studies that they suffer from a high charge injection barrier, a problem exacerbated in films containing multiple layers of nanocrystals. We introduce a self-assembled monolayer (SAM) active layer that improves charge injection. We identified a bifunctional capping ligand that simultaneously enables the self-assembly of CsPbBr₃ c-NCs while passivating surface traps. We report, as a result, SAM-based LEDs exhibit a champion EQE of ~12% [CIE of (0.132, 0.069) at 4.0 V with a luminance of 11 cd/m²], and 10-fold-enhanced operating stability relative to the best previously reported Rec. 2100-blue perovskite LEDs.