Recently, the research groups of Professor Ni Zhenhua from the School of Electronic Science and Engineering of Southeast University, Professor Lv Junpeng from the School of Physics, Professor Liu Hongwei from the School of Physical Science and Technology of Nanjing Normal University, and Professor Zhou Peng from the School of Microelectronics of Fudan University have jointly proposed a van der Waals light-emitting diode with an external quantum efficiency exceeding 10% at room temperature based on two-dimensional perovskite and combined with a low-temperature van der Waals transfer process. The relevant results were published in Science Advances under the title "Van der Waals integrated single-junction light-emitting diodes exceeding 10% quantum efficiency at room temperature".

At present, the main bottleneck in the development of optoelectronic integrated chips is the lack of high-performance on-chip light sources. Among many material systems, two-dimensional semiconductor materials have become ideal materials for building a new generation of optoelectronic systems and breaking through the bottleneck of high-performance on-chip light sources due to their excellent optoelectronic properties and integration advantages. Although light-emitting diode devices based on two-dimensional semiconductors have made important progress at this stage, their luminous efficiency under high injection state at room temperature is generally low, which limits their practical application in optoelectronic chips.

This study uses the characteristics of two-dimensional semiconductor materials with multiple quantum wells and combines them with low-temperature van der Waals transfer technology to achieve high-efficiency light-emitting diodes that can be integrated on-chip. Taking advantage of the two-dimensional perovskite multi-quantum well structure and high fluorescence quantum yield, combined with the low barrier height of the graphene/two-dimensional perovskite interface, the external quantum efficiency of more than 10% at room temperature is achieved through the efficient carrier tunneling-recombination process, which is the highest level of current van der Waals light-emitting diodes. This scheme is universal and can be extended to other layered two-dimensional materials. This achievement has laid a good foundation for the future development of large-area, high-efficiency, high-brightness, on-chip integrated two-dimensional semiconductor light-emitting devices.

Ni Zhenhua, Lv Junpeng, Liu Hongwei, and Zhou Peng are the co-corresponding authors of this article. Hu Zhenliang, a postdoctoral fellow at the School of Physics, Southeast University, and Fu Qiang, a doctoral student, are the co-first authors of this article. This work was funded by the National Key R&D Program, the National Natural Science Foundation, and the Jiangsu Natural Science Foundation.