Abstract
A major efficiency limit for solution-processed perovskite optoelectronic devices, for example light-emitting diodes, is trap-mediated non-radiative losses. Defect passivation using organic molecules has been identified as an attractive approach to tackle this issue. However, implementation of this approach has been hindered by a lack of deep understanding of how the molecular structures influence the effectiveness of passivation. We show that the so far largely ignored hydrogen bonds play a critical role in affecting the passivation. By weakening the hydrogen bonding between the passivating functional moieties and the organic cation featuring in the perovskite, we significantly enhance the interaction with defect sites and minimize non-radiative recombination losses. Consequently, we achieve exceptionally high-performance near-infrared perovskite light-emitting diodes with a record external quantum efficiency of 21.6%. In addition, our passivated perovskite light-emitting diodes maintain a high external quantum efficiency of 20.1% and a wall-plug efficiency of 11.0% at a high current density of 200 mA cm−2, making them more attractive than the most efficient organic and quantum-dot light-emitting diodes at high excitations.
| Original language | English |
|---|---|
| Pages (from-to) | 418-424 |
| Number of pages | 7 |
| Journal | Nature Photonics |
| Volume | 13 |
| Issue number | 6 |
| DOIs | |
| State | Published - Jun 1 2019 |
| Externally published | Yes |
Funding
We thank O. Inganäs, T.C. Sum, S.S. Lim, J. Zhang, W. Tress, W. Chen, Y. Puttisong, Y.T. Gong, C.Y. Kuang and C. Deibel for useful discussions. This work is supported by the ERC Starting Grant (717026), the National Basic Research Program of China (973 Program, grant number 2015CB932200), the National Natural Science Foundation of China (61704077, 51572016, 51721001, 61634001, 61725502, 91733302 and U1530401), the Joint Research Program between China and the European Union (2016YFE0112000), the Natural Science Foundation of Jiangsu Province (BK20171007), the National Key Research and Development Program of China (grant number 2016YFB0700700), the European Commission Marie Skłodowska-Curie Actions (691210), the Swiss National Science Foundation (CR23I2-162828), Nanyang Technological University start-up grant M4081924, and the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University (Faculty Grant SFO-Mat-LiU no. 2009-00971). The TEM measurements were performed at the Facility for Analysis, Characterization, Testing and Simulation (FACTS) in Nanyang Technological University, Singapore. A.P. and T.B. acknowledge financial support from the ERC Consolidator grant SOPHY (grant agreement number 771528). A.P. and A.J.B. acknowledge the project PERSEO-‘Perovskite-based solar cells: towards high efficiency and long-term stability’ (Bando PRIN 2015-Italian Ministry of University and Scientific Research (MIUR) Decreto Direttoriale 4 novembre 2015 n. 2488, project number 20155LECAJ) for funding. W.X. is a Wenner-Gren Postdoc Fellow; F.G. is a Wallenberg Academy Fellow.
