Compared to traditional electronic chips, optoelectronic chips offer higher transmission speeds and bandwidth. Among them, optical signals can be transmitted at the speed of light, offering significant advantages in high-speed communication and data transmission fields. Nano-devices with single molecules as optoelectronic functional centers are expected to meet the demand for device miniaturization and serve as the cornerstone for future molecular optoelectronic devices. Recently, researchers from the College of Chemistry and Molecular Engineering at Peking University, led by Professor Xuefeng Guo, along with collaborators, achieved high quantum yield radiation of phosphorescence/fluorescence by covalently anchoring molecular bridges insulated and protected by cyclodextrins between graphene electrodes. This breakthrough has been successfully applied in logic operations and real-time communication. The related work has been published online under the title 'Logic Operations and Real-Time Communication via Tunable Excited States in Single-Molecule Optoelectronic Chips' in the journal 'Chemistry'.
Professor Guo Xuefeng explained that to date, there is still room for improvement in the performance and stability of individual molecules in devices, including the switch ratio of field-effect transistors, quantum yield of light-emitting diodes, and operation frequency of logic devices. Among these, the coupling between molecules and the external environment is a critical parameter. Strong coupling may lead to hybridization of molecules with the outside world, while weak coupling may weaken the modulation effect of external stimuli, calling for further development in molecular engineering, interface engineering, and electrode engineering.
"Therefore, based on our previous series of studies, our team has developed another multifunctional single-molecule optoelectronic device, consisting of a platinum-centered molecular bridge encapsulated by cyclodextrins, graphene electrodes with nanoscale gaps, and a silicon substrate. The two cyclodextrins on both sides weaken the coupling between the molecule and the environment, thereby avoiding corresponding non-radiative processes. The graphene electrodes can form a robust covalent interface with the molecule, further achieving multi-molecule integration," said Professor Guo Xuefeng.
Yang Chen, the first author of the article and a postdoctoral fellow at Peking University, stated that further tuning and selective emission of fluorescence and phosphorescence could enable comprehensive binary and ternary logic operations as well as real-time communication. Multifunctional and efficient single-molecule optoelectronic devices bridge molecular electronics with practical semiconductor applications, demonstrating the disruptive advantages of single-molecule optoelectronic devices. They provide technical support for breaking technological barriers and developing new principle devices, representing an important step for single-molecule devices to move from the laboratory to industrial production.
