| Title | Boosting Efficiency and Curtailing the Efficiency Roll-Off in Green Perovskite Light-Emitting Diodes via Incorporating Ytterbium as Cathode Interface Layer |
| Authors | Ali, Muhammad Umair Miao, Jingsheng Cai, Jinqiao Perepichka, Dmitrii F. Yang, Huai Meng, Hong |
| Affiliation | Peking Univ, Sch Adv Mat, Shenzhen Grad Sch, Shenzhen 518055, Peoples R China Peking Univ, Dept Mat Sci & Engn, Coll Engn, Beijing 100871, Peoples R China McGill Univ, Dept Chem, Sherbrooke, PQ H3A 0B8, Canada |
| Keywords | HIGH-PERFORMANCE HOLE INJECTION |
| Issue Date | 22-Apr-2020 |
| Publisher | ACS APPLIED MATERIALS & INTERFACES |
| Abstract | Perovskite light-emitting diodes (PeLEDs) exhibit high external quantum efficiencies (EQEs), emerging as a nextgeneration lighting and display technology. Nevertheless, they suffer from severe efficiency roll-off at high luminance, particularly in the case of blue and green emissions, which is one of the major bottlenecks in their industrial applications. Here, we attack this problem using a rare-earth metal, Yb, as cathode interface layer (CIL) for green PeLEDs. By adopting a new device configuration of ITO/TFB/FA-based quasi-2D perovskite/TPBi/Yb/Ag, we achieved a peak current efficiency (CE) of 22.3 cd/A with a corresponding EQE of 5.28% and a high maximum luminance of 19 160 cd/m(2). Importantly, the maximum CE of 22.0 cd/A at 2000 cd/m(2) slightly decreased to 16.8 cd/A at 5000 cd/m(2) and maintained a still-decent value of 12.0 cd/A at a high luminance of 10 000 cd/m(2), exhibiting a remarkably low efficiency roll-off. Our Yb-incorporated devices significantly outperformed the PeLEDs containing conventional CILs, including Mg and Liq, in terms of peak efficiency, efficiency roll-off, and operational lifetime. We attribute this encouraging performance to barrier-free, efficient electron injection enabled by the low work function of Yb (2.6 eV), which led to a high electron current, nearly approaching the hole current in hole-dominant PeLEDs, as confirmed by the singlecarrier device measurements. In addition, we also present Yb-incorporated PeLEDs containing Cs-based quasi-2D perovskite as the emissive layer, which displayed an impressive CE of 51.3 cd/A with a corresponding EQE of 16.4% and a maximum luminance of 14 240 cd/m(2), and still demonstrated a reduced efficiency roll-off comparing to that of the Liq-based equivalent. These results unveil the inspiring prospects of Yb as an efficient CIL for PeLEDs toward high efficiency with curtailed roll-off. |
| URI | http://hdl.handle.net/20.500.11897/588519 |
| ISSN | 1944-8244 |
| DOI | 10.1021/acsami.0c00950 |
| Indexed | SCI(E) Scopus |
| Appears in Collections: | 新材料学院 工学院 |
