Quantum-Scale Information Processing Via Molecular Logic Gates: A Review on the History, Properties, and Derived Technologies

It has been demonstrated in the electronics industry, that miniaturizing the silicon components below 10 nm and integrating million of them in a chip would not be a good idea. This is due to the high-energy consumption, high-cost fabrication, the limitations originating  from quantum mechanics, and technological difficulties that obstacle the further miniaturization of electronic devices. Therefore, researchers should think about something out-of-the silicon-box to fabricate a more compacted electronic device. Accordingly, through evaluating and discovering the wide range of molecular structures which enable effective data encoding and manipulation, molecular informatics can be an appropriate alternative to the conventional digital logic. In this regard, molecular platforms can be considered as computing devices, which convert the physical/chemical inputs into the desired outputs by employing a set of logic operations. This field is related to the hardware subcategory of quantum computing technologies, and therefore, the fabrication of more efficient molecular electronic devices and sensors can produce positive meaningful effects on the defense and security abilities of a country. In this review paper, a brief history of molecular devices is initially presented because awareness of the evolution of a scientific subject can underpin more fundamental progress. In the next step, the main reasons for changing the paradigm toward molecular devices are explained, and by introducing the logic gates used, the fundamental and technological limitations of conventional devices are reviewed. Then, the different functionalities of molecular logic gates in the two aspects of molecular electronics and chemical logic sensors are discussed in a detailed way to demonstrate the capabilities of molecules in different computational systems.