Recently, a new breakthrough has been made in perovskite-based light-emitting diodes and the external quantum efficiency is 21.6%, which is a new world-record. The work is led by Professor Liu Limin from the School of Physics of Beihang University, in close collaboration with researchers from Linköping University in Sweden and the research group led by Academician Huang Wei from Northwestern Polytechnical University.
Lead halide perovskites has been the focus of intense research interest for its cheapness and good light-emitting properties as a kind of semiconductor materials. They also have been extensively studied in light-emitting diodes (LED), photovoltaiccells(PV),laser, photodetectors and other fields.Although solution-processed perovskite materials have performed well in various optoelectronic devices, a major efficiency limit for them is trap-mediated non-radiative losses. Defect passivation using organic molecules has been identified as an attractive approach to tackle this issue. However, the implementation of this approach has been hindered by a lack of deep understanding of how the molecular structures influence the effectiveness of passivation.
To solve the scientific problem, the research group led by Professor Liu initially studied how Pb12 will influence excition’s lifespan. Based on the previous studies, Professor Liu, together with researchers from Linköping University in Sweden from Northwestern Polytechnical University, collaboratively put forward a mechanism of hydrogen bonds formation and passivation effect in passivation molecules. By weakening the hydrogen bonding, they significantly enhanced the passivation effect and minimized non-radiative recombination losses in perovskite film. Then, a new approach to minimize non-radiative recombination losses in perovkite optoelectronic devices has been provided, which may further enhance the performance of in LED, PV, laser, and photodetectors.
Fig. 1 The influence ofhydrogen bonds on passivation effects
Further reading is availablein:
Rationalmolecular passivation for high-performance perovskite light-emitting diodes. Nature Photonics2019, doi10.1038/s41566-019-0390-x。
The work was supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China and other organizations.
The research group led by Professor Liu has long been committed to studying the interface physics. Since entering the School of Physics of Beihang University, he has published 4 papers as a corresponding author inNatureand his research work has gained extensive attention. Professor Liu was invited to give a review paper (Surf.Sci. Rep.73, 58(2018)) in 2018 at the invitation ofSurface Science Reportsand is working on another paper on the results of his work at the invitation ofAdvanced Theory and Simulations.
Further reading is available at: