Single-molecule science focuses its perspective on the microscopic scale, reveals a series of novel phenomena and properties different from macroscopic materials, and effectively circumvents the interference of ensemble average. Meanwhile, the construction of functional devices based on single molecules is expected to meet the demand for miniaturization and high integration of electronic devices, thus conforming to the national strategies for device miniaturization in the information field. Specifically, single-molecule science studies multi-dimensional contents, such as molecular conformation design, single-molecule super-resolution imaging/mechanical manipulation, and characterization/theoretical simulation of single-molecule physical and chemical properties. As an advanced interdisciplinary field, single-molecule science can inject impetus into the continuous development of multiple disciplines, such as physics, chemistry, biology and materials, and has become the commanding heights of competition in the world. There are many interesting and elegant opportunities in the field of single-molecule science, and great progress has been made so far. For example, single-molecule junction electrical platforms allow real-time adjustment of the physical properties of single molecules and capture of transition states in chemical reactions. At the same time, single-molecule junctions also show satisfactory results in the construction of single-molecule electronic devices including field-effect transistors, rectifiers and switches. Advances in micro-nano characterization technologies represented by high-resolution scanning probes enable molecular imaging at the single-bond level. In the meantime, with the help of atomic force microscopy, magnetic tweezers, optical tweezers and other sophisticated mechanical instruments, it is possible to achieve reliable manipulation of the movement and chemical reaction process of individual molecules. In addition to these, the combination of nanomaterials and single molecules promotes the implementation of new functions. For example, the nanopore platform based on current signals not only contributes to the industrialization of single-molecule DNA sequencing, but allows real-time and label-free characterization of the conformation and sequence of biological molecules such as proteins. During this process, Chinese scholars have actively made plenty of outstanding contributions to the development of single-molecule science. Up to now, a series of exciting breakthroughs and challenges have emerged in the field of single-molecule science. Based on the above background, we comprehensively summarize the recent progress in single-molecule research with the theme of single-molecule science. Firstly, the significance of exploring single-molecule science and technology is expounded from the perspective of scientific research and practical application. Subsequently, major advances in multidimensional technologies are introduced in detail, including electronics based on single-molecule junctions, mechanics and optics based on scanning probes, and biophysical characterization based on nanopores. Finally, we conclude with a comprehensive outlook on potential opportunities and challenges of single-molecule science in the future. Although a series of achievements have been made, it must be noted that it is still a challenge to directly apply the experimental findings of single-molecule science to practical applications. In the future, the preparation and application of singlemolecule devices, the characterization and regulation of novel physical properties of single molecules, the refinement and improvement of the theoretical framework of single-molecule reactions, the development and promotion of single-molecule biophysics and sequencing technology, and the establishment and optimization of the theoretical model of single-molecule science all need to be further explored. As the title indicates, the study of single molecules presents both challenges and opportunities. After all, a single molecule is the smallest stable unit in the material world. Only with patience and innovation can we unveil the infinite charm of single-molecule science.
