Professor Guo Xuefeng's research team from the School of Chemistry and Molecular Engineering at Peking University collaborated with relevant teams to accurately and real-time detect and regulate the shell opening characteristics of donor acceptor double radical molecules using a graphene based single-molecule device platform. They also revealed how temperature, electric field, and magnetic field external factors affect the spin state conversion mechanism of double radicals, which has great application prospects in future quantum communication and computing. The relevant research results were recently published in Nature Nanotechnology under the title of "Regulation of Quantum Spin Conversion in Single Molecule Free Radicals". Today, with the rapid development of information technology, the intrinsic properties of electron spin have become increasingly prominent in logical operations, data storage, and information retrieval. With the continuous progress of experimental technology, the study of electron spin is gradually deepening from the macroscopic level to the nanoscale or even single spin level, opening up a broad path for spin related applications. However, scientists from around the world still face significant challenges in detecting and regulating single spins. In this study, based on the principles of molecular engineering, the team used covalent bonds to anchor donor acceptor double radical molecules onto graphene nanoelectrodes, successfully constructing a single molecule free radical device and achieving stable single electron transfer performance in low-temperature environments. Subsequently, the team fitted the singlet triplet energy gap based on magnetic testing of free radical molecules at different temperatures, and observed three different conductivity states and their conversion relationships through real-time current testing. These states were then classified and analyzed in detail. The fitting results of activation energy indicate that an increase in temperature will facilitate the transition from a closed shell structure to an open shell structure, especially to the open shell trilinear state. In the study of electric field effects, the team successfully utilized the electric field to reduce the energy barrier for the transition from singlet to triplet states and promote the transition from closed shell singlet to open shell triplet states by applying bias voltage. The role of single molecule free radical devices in magnetic field regulation is equally significant. At low temperatures, single-molecule free radical devices exhibit a significant positive magnetoresistance effect, and the enhancement of the magnetic field promotes the transition from a closed shell structure to an open shell trilinear state, but at the same time suppresses the transition to an open shell monolinear state. Guo Xuefeng stated that this study demonstrates the important role of single-molecule electrical methods in directly detecting and regulating the spin state of free radical molecules. If stable quantum spin states can be further achieved in room temperature environments, this research achievement will provide important chip technology support for the development of quantum information systems based on molecular spin, and promote the deeper development of electronic information technology. (Lai Xin She)