Marked Efficiency Improvement of FAPb0.7 Sn0.3 Br3 Perovskite Light-Emitting Diodes by Optimization of the Light-Emitting Layer and Hole-Transport Layer

• Main Authors: An, H. (Author), Cui, X. (Author), Hu, L. (Author), Li, B. (Author), Qiu, M. (Author), Wang, K. (Author), Wang, N. (Author), Wang, W. (Author), Wang, Z. (Author), Wu, D. (Author), Xiang, B. (Author), Ye, Z. (Author)
• Format: Article
• Language: English
• Published: MDPI 2022
• Subjects: double hole transport structure; FAPb0.7 Sn0.3 Br3 film; light-emitting layer thickness; perovskite light-emitting diode
• Online Access: View Fulltext in Publisher
• ISBN: 20794991 (ISSN)
• DOI: 10.3390/nano12091454

Highly luminescent FAPb0.7 Sn0.3 Br3 nanocrystals with an average photoluminescence (PL) quantum yield of 92% were synthesized by the ligand-assisted reprecipitation method. The 41-nm-thick perovskite film with a smooth surface and strong PL intensity was proven to be a suitable luminescent layer for perovskite light-emitting diodes (PeLEDs). Electrical tests indicate that the double hole-transport layers (HTLs) played an important role in improving the electrical-tooptical conversion efficiency of PeLEDs due to their cascade-like level alignment. The PeLED based on poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,40-(N-(p-butylphenyl))-diphenylamine)] (TFB)/poly(9-vinylcarbazole) (PVK) double HTLs produced a high external quantum efficiency (EQE) of 9%, which was improved by approximately 10.9 and 5.14 times when compared with single HTL PVK or the TFB device, respectively. The enhancement of the hole transmission capacity by TFB/PVK double HTLs was confirmed by the hole-only device and was responsible for the dramatic EQE improvement. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.