Sub-nanometer materials(SNMs) define the emergent functional material system with their characteristic dimensions at sub-1 nm scale and they can be generally constructed with the sub-1 nm molecular clusters as the basic structural units. Due to their extremely small sizes, the sub-nm scale particles possess diffusive dynamics in their bulk with an energy level close to typical thermal fluctuation. Meanwhile, the volume fraction of surface structures becomes dominant and the dynamics of surface structures can be distinguishable from their diffusive dynamics. The research on the dynamics of SNM is key to the understanding of their unique properties in comparison to small molecule and nano-material systems. This review paper summarizes recent progresses in the studies of relaxation dynamics of SNM upon the combinatory application of X-ray/neutron scattering, dielectric spectroscopy and rheometric technology. The functional materials inspired by the dynamics investigations with applications in mechanical strengthening, ion conduction, and gas separation are also reviewed. In the end, challenges and outlooks on the theories, characterizations and the prediction of possible new functionalities of SNMs are discussed.

亚纳米材料（SNM）以其亚1纳米尺度的特征尺寸定义了新兴的功能材料系统，它们通常可以以亚1纳米分子簇为基本结构单元构建。由于尺寸极小，亚纳米级粒子在其体积内具有扩散动力学，其能级接近典型的热波动。同时，表面结构的体积分数变得占主导地位，并且表面结构的动力学可以与其扩散动力学区分开来。与小分子和纳米材料系统相比，SNM 动力学研究是理解其独特性质的关键。本文综述了X射线/中子散射、介电谱和流变技术相结合的SNM弛豫动力学研究的最新进展。还回顾了受动力学研究启发的功能材料在机械强化、离子传导和气体分离中的应用。最后，讨论了 SNM 的理论、表征和可能的新功能预测的挑战和展望。