A group of Chinese scientists at the Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences, under the direction of Professor Yuchen Wu, have created a novel technique for the remote epitaxial growth of continuous crystalline perovskite thin films, according to a study published in Nature Nanotechnology on January 15th, 2025.
Remote epitaxial crystalline perovskites for ultrahigh resolution micro-LED displays. Image Credit: Prof. WU Yuchen’s group
Microscale light-emitting diodes, or micro-LEDs, are emerging as a next-generation display technology for wearable technology, augmented and virtual reality, and optical communications. Metal-halide perovskites are promising options for brilliant LED displays because of their high potential for effective light emission, long-range carrier transport, and scalable manufacturing.
However, producing thin-film perovskites for micro-LED displays presents significant problems. Thin-film perovskites, for example, may emit inhomogeneous light and have unstable surfaces when subjected to lithography. For these reasons, solutions are required to make thin-film perovskites compatible with micro-LEDs.
The researchers have made substantial progress toward overcoming these difficulties.
Researchers devised a novel approach for growing continuous crystalline perovskite thin films from a distance. This advancement enables flawless integration into ultrahigh-resolution micro-LEDs with pixels smaller than 5 μm.
The study’s findings disclose a distant epitaxial growth process that uses a graphene interlayer to form continuous crystalline perovskite thin films over a 4 cm2 area. This approach efficiently removes grain boundaries, producing a pure out-of-plane crystallographic orientation.
The researchers used single-crystalline, freestanding perovskite thin films to obtain exceptional results for micro-LEDs, including electroluminescence efficiency of 16.1%, brightness of 4 × 105 cd m-2, and ultrahigh resolution with a pixel size of 4 μm.
The free-standing perovskites are simply integrated into commercial electronic platforms, allowing for independent and dynamic control of each pixel. This functionality can be used for both static images and video displays.
By combining many perovskite components, this technique enables the creation of full-color micro-LED displays. Ultracompact photonic devices can also be developed by monolithically integrating the perovskite films with nanophotonic structures like photonic crystals and resonant metasurfaces.
The National Natural Science Foundation of China, the Youth Innovation Promotion Association of CAS, and the Chinese Ministry of Science and Technology all funded this study.
Journal Reference:
Yuan, M., et. al. (2024) Remote epitaxial crystalline perovskites for ultrahigh-resolution micro-LED displays. Nature Nanotechnology. doi.org/10.1038/s41565-024-01841-9