Researchers from NUAA and the University of Tokyo introduce a new material called "phosphorus-lithium double-helix nanoribbon". [Photo/en.nuaa.edu.cn]
In a groundbreaking advancement, a research team from Nanjing University of Aeronautics and Astronautics led by Guo Wanlin and Tai Guoan, both professors at the university, and in partnership with a Japanese team steered by Associate Professor Naoji Matsuhisa from the University of Tokyo, has successfully introduced a new material called "phosphorus-lithium double-helix nanoribbons".
This innovative material addresses the inherent fragility of low-dimensional phosphorus materials, showing a general approach for stabilizing active low-dimensional materials and paving the way for applying phosphorus-based nanostructures in biomedical engineering and quantum technologies. The research findings were recently published in the esteemed journal Science Advances.
As a leader in the field of nanoscale physical mechanics, Guo's team has long been dedicated to the structural design of low-dimensional materials and the study of multi-field coupling mechanisms. This breakthrough once again underscores NUAA's international research prowess in this domain.
Phosphorus-based materials are considered promising candidates for high-end optoelectronic devices due to their excellent conductivity and luminescence properties. However, their susceptibility to rapid oxidation and degradation in ambient conditions has posed a significant challenge to their practical application. Previous solutions, such as protective coatings, often compromised the materials' inherent properties and failed to provide long-term stability under complex conditions.
To overcome this challenge, the research team adopted an "atomic-level structural design" strategy. Through theoretical predictions and experimental validation, they successfully fabricated a double helix nanoribbon with alternating phosphorus and lithium atoms. This novel material exhibits a unique, highly ordered helical structure, resembling a "Chinese knot", and represents a rare example of a non-centrosymmetric inorganic double helix crystal.
Detailed analysis using electron microscopy revealed these nanoribbons are exceptionally thin yet structurally robust, with a thickness of just 3.11 nanometers (equivalent to five atomic layers), a width reaching hundreds of nanometers, and a length exceeding 10 micrometers. Remarkably, these nanoribbons exhibit superior stability, maintaining structural integrity in air at temperatures of 225 C, remaining unchanged after 30 days in water, and withstanding immersion in strong acid for an hour without lattice degradation.
Beyond their stability, these nanoribbons demonstrate impressive optical capabilities. Their bandgap can be flexibly tuned, akin to adjusting the brightness of a light bulb, and they exhibit significant polarization-dependent optical responses, making them highly suitable for applications in polarization-sensitive photodetection and nonlinear optical conversion.
Notably, leveraging the nanoribbons' exceptional water stability, the team successfully integrated them with hydrogels to develop a composite hydrogel with high conductivity, self-healing properties, and efficient photothermal conversion. Potentially, they can be applied to photothermal imaging, precision temperature control, photothermal therapy, and flexible bioelectronic devices, offering a novel platform for the development of smart medical materials.
"The core significance of this achievement lies in introducing the 'double helix' structural paradigm from biological systems into the field of inorganic low-dimensional materials," said Guo, who is also an academician at the Chinese Academy of Sciences.
This research was completed with the contribution of NUAA doctoral graduates Hou Chuang and Lu Huan as first authors, with professors Guo, Tai and Matsuhisa serving as corresponding authors.
